Allison trans troubleshooting guide-Allison Transmission Problems | Drivetrain Resource

Okay, finally going to start my own thread on this insert your favorite curse here. I found that there was a short somewhere in the wire from the DDEC2 to the speed sensor. I have replaced that wire but have not been able to get the ECU to 'let go' of the error. I also can not get an error code out of the ECU it just beeps continuously no matter what position I put the Transmission Test switch in. Background: Problem started when I was going to get tires.

Allison trans troubleshooting guide

Allison trans troubleshooting guide

Allison trans troubleshooting guide

Allison trans troubleshooting guide

It will be necessary tdans provide battery power at Allison trans troubleshooting guide 41 of the way connector in order to energize the neutral start relay. The vehicle is equipped with a lever-type shift selector refer to Figure Yukranian girl naked or replace the internal wiring harness. Take the ECU to the Allison shop to have it tested since it is out. Allison Transmission DOC 7. I think I'll permanently move it after seeing how many issues there are with these bulkhead connectors. TCMs are available in both 12V and 24V congurations to match the conguration of the vehicle electrical system.

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Wire will be connected to the following wire Allison trans troubleshooting guide the transmission internal harness: TID B. Never use wire ties inside the transmission, to hold connector components together in the place of a connector lock, or in Adult mytext place of the correct strain relief components and clips used to fasten harnesses to the vehicle or to retain vehicle connectors unless OEM approved for ttrans location and vehicle component being repaired. Troubldshooting external harnesses are OEM supplied. Were any wiring defects found? Then shift to N Neutral and allow the engine to remain at idle rpm. Disconnect the way connector at the TCM. Use the Allison shift selector to review the current status of any of these functions, provided the function being Allisoh is in its specific display mode. Connector and pin corrosion caused by moisture in connectors. If the code does not reappear, it may be an intermittent problem. DVOM continuity beeper will sound, or reading will go to zero Ohms when meter is probing between this wire and Allison trans troubleshooting guide ground. Message over the SAE J Allison trans troubleshooting guide interface. The main regulator valve regulates the discharge pressure at the oil pump. The gerotor gear set guice the oil pump assembly turns at engine speed and pressurizes the fluid.

Allison Transmission, Inc.

  • This service manual mainly contents the necessary technical information for operation performed in a service workshop.
  • We make every effort to keep our service information current and accurate.

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The transmission fluid temperature sensor is part of the internal wiring harness and measures the sump temperature. These warnings and cautions are not exhaustive. Using a digital multimeter DMM , test for continuity 0 Ohms between pin 20 TID wire and pin 1 in the transmission way connector. Pushbutton Shift Selector. The TPS contains a pull actuation cable and a potentiometer.

Allison trans troubleshooting guide

Allison trans troubleshooting guide

Allison trans troubleshooting guide. Allison Transmission Parts Catalog PDF

Hot Check Procedure 1. Operate the transmission in D Drive range until normal operating temperature is reached: Sump temperatureC F Converter-out temperatureC F. If a transmission temperature gauge is not present, check fluid level when the engine water temperature gauge has stabilized and the transmission has been operated under load for at least one hour.

Apply the parking brake and block the wheels. Allow the engine to idle rpm. Check fluid level. If the fluid level is not within the HOT RUN band, add or drain as necessary to bring the fluid level to within the band. Containers or fillers that have been used for antifreeze or engine coolant solution must NEVER be used for transmission fluid. Antifreeze and coolant solutions contain ethylene glycol which, if put into the transmission, can cause clutch plate failure.

Foreign Material Prevent foreign material from entering the transmission by using clean containers, fillers, etc. Lay the dipstick in a clean place while filling the transmission. The hydraulic fluids oils used in Allison transmissions directly affect transmission performance, reliability, and durability. Consult your Allison Transmission dealer or distributor before using any fluid types except those fluids qualified for use in Allison transmissions. Disregarding minimum fluid temperature limits can result in transmission malfunction or reduced transmission life.

Table 24 lists the minimum fluid temperatures at which the transmission may be safely operated. Preheat with auxiliary heating equipment or by running the equipment or vehicle with the transmission in neutral for a minimum of 20 minutes before attempting range operation. The codes contained in the list have information recorded as shown in the table below codes are examples.

Access to the code list position, DTC, and active indicator is through the shift selector display. Code List Position shift selector only. The position which a code occupies in the code list. The diagnostic trouble code number referring to the general condition or area of fault detected by the TCM. Double click on the numerical code in the DTC column to link to the specific troubleshooting instructions for the DTC.

Active Indicator. Indicates when a DTC is active. Historic Indicator. Indicates when the DTC has met sufficient criteria to be stored in long term memory. Sufficient criteria may mean the DTC occurred over a specific span of time or over multiple test cycles.

Check Trans Indicator. Failure Records Indicator. Indicates when Failure Records are present. Double click on Y in the Failure Records column to display failure record information. Provides a brief description of the DTC. The method of reading and clearing codes described in this section refers to entering the diagnostic display mode of the shift selector.

The diagnostic display mode may be entered for viewing of codes at any speed. If an oil level sensor is present, the fluid level is displayed first. Reading Codes 1. The code list or queue position is the first item displayed, followed by the DTC. Each item is displayed for about one second. The display cycles continuously until the next code list position is accessed by pressing the MODE button.

No DTCs are logged after an empty code position. Clearing Active Indicators. A DTCs active indicator can be cleared, which allows the code inhibit to be cleared but remains in the queue as inactive.

The active indicator clearing methods are: 1. Power downAll active indicators are cleared at TCM power down. Self-clearingSome codes will clear their active indicator when the condition causing the code is no longer detected by the TCM.

ManualSome active indicators can be cleared manually, while in the diagnostic display mode, after the condition causing the code is corrected. If an active indicator is cleared while the transmission is locked in a forward range or reverse fail-to-range , the transmission will remain in the forward range or reverse after the clearing procedure is completed.

Neutral must be manually selected. To clear active indicators or all codes: 1. Enter the diagnostic display mode. All active and inactive indicators are cleared. All active indicators will be cleared at TCM power down. Codes that cannot be manually cleared will remain. Exiting the diagnostic display mode. Exit the diagnostic display mode using one of the following procedures: 1.

On a pushbutton shift selector, press the Up and Down arrow buttons at the same time or press any range button, D, N, or R. The shift D, N, or R is commanded if not inhibited by an active code. On a lever shift selector, momentarily press the MODE button or move the shift lever to any shift position other than the one it was in when the diagnostic display mode was activated.

If the shift is inhibited, the TCM will continue to command the current transmission range attained and the lever should be returned to its original position. Wait until timeout approximately 10 minutes and the system will automatically return to the normal operating mode. Turn off power to the TCM turn off the vehicle engine at the ignition switch. Inhibit all shifts. Display the range attained. Ignore any range selection inputs from the pushbutton or lever shift selector.

Do not adapt shifts when a code with the DNA response is active. All Segments DisplayedAll display segments will be illuminated during shift selector initialization. May inhibit retarder operation if not using J data link May inhibit retarder operation if not using J data link Use default throttle values. Freezes shift adapts. Use default throttle values. Use hot mode shift schedule.

Holds fourth range. TCC is inhibited. Ignore defective strip selector inputs None None Use default sump temp. Use default values, inhibit SEM Use default values, inhibit SEM Use default values Maintain range selected, observe gear shift direction circuit Use default values Maintain range selected, observe gear shift direction circuit Ignore shift selector inputs Ignore shift selector inputs None Maintain range selected, observe gear shift direction circuit None.

Allow 2 through 6, N, R. Inhibit retarder and TCC operation Inhibit retarder operation. Beginning The Troubleshooting Process 1. Access DTCs by using: The shift selector display. When a problem exists but a DTC is not indicated, refer to Section 8, General Troubleshooting of Performance Complaints for a listing of various electrical and hydraulic problems, their causes, and remedies.

Refer to Section If the code reappears, refer to Section 65, Table Table 62 lists DTCs and their. Service Tool or the code display procedure described in Section Refer to.

Section 8, General Troubleshooting of Performance Complaints, for the possible cause s of the problem. Use pressure gauges as necessary to evaluate hydraulic conditions. Solenoid Locations Solenoid locations in the control module are as illustrated in Figure Refer to Figure 64 as necessary when using the DTC schematics.

Diagnostic Trouble Code Schematics The diagnostic trouble code schematics in this section show wiring for the optional oil level sensor, Prognostic Filter Life Switch, and retarder, as applicable.

If your transmission is not equipped with an oil level sensor, retarder, or Prognostic Filter Life Switch, disregard the portions of the schematic pertaining to those optional pieces of equipment. Refer to the appropriate transmission service manual for solenoid replacement procedures.

The TCM is connected to the retarder request sensor by:. The TCM interprets this signal as a percent retarder requested. Conditions for Running the DTC. TCM may inhibit retarder operation, if not using the J data link for retarder request signal. Diagnostic Aids. The code can be caused by: Faulty wiring. Faulty connections to the retarder request sensor or retarder control device.

A faulty retarder request sensor resistance module. A faulty retarder control device. A faulty TCM. DTC C can be caused by an open or short-to-ground in either the 5V reference wire or retarder request signal wire An open or short-to-ground in the common 5V reference causes a sensor failed low code for the other devices as well.

An open or short-toground on wire will cause a DTC C only. Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions: A bent terminal A backed-out terminal A damaged terminal Poor terminal tension A chafed wire A broken wire inside the insulation.

The numbers below refer to step numbers on the diagnostic table. Tests for an active DTC. Tests for damaged wiring in external harness. Tests for retarder request sensor functionality. Start the engine. Record the failure records. Clear the DTC and drive the vehicle. Attempt to duplicate same operating conditions observed in failure records. It may also indicate an open or short-to-ground in either the 5V reference wire or retarder request signal wire Did DTC C return? Turn ignition OFF. Inspect the routing of 5V reference wire , retarder request signal wire , and analog return ground wire between the TCM and the retarder request sensor.

Disconnect the way connector from the TCM. Leave the TCM disconnected. Test for opens or shorts-to-ground on wires and Was chafing or wire damage found? Harness repairs performed by Allison Transmission distributors and dealers are not covered by Allison Transmission warranty. Coordinate with the vehicle OEM to repair or replace the vehicle wiring. Is the repair complete? Turn ignition ON. Replace the retarder request sensor resistance module. Is replacement complete? After replacing the retarder request sensor, perform the following:.

Replace the retarder control device. Investigate thoroughly before replacing the TCM. Refer to TCM diagnostic procedure, Section Is Section 36 complete? To verify the repair: 1. Clear the DTC. Drive the vehicle under conditions noted in failure records. Confirm with the service tool in the test passed section that the diagnostic test was run.

Did the DTC return? DTC C can be caused by a short-to-battery in the 5V reference wire or retarder request signal wire DTC C can also be caused by an open in analog return wire A short-to-battery in the 5V reference wire or open in analog return wire causes a sensor failed high code for the other devices as well.

A short-to-battery in retarder request signal wire will produce a DTC C only. It may also indicate a short-to-battery on 5V reference wire or an open on analog return wire Test for shorts-to-battery on wires and , and opens on wire Vehicles not equipped with electronically-controlled engines have a TPS attached to the engine fuel control linkage.

The TPS is a sliding resistor sensor potentiometer actuated by a mechanical linkage. The other TPS terminal connects to ground. At each increment of 0.

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. An open or short-to-ground on wire will cause a DTC P only. Tests for the proper adjustment of TPS. Tests for dead spots in the potentiometer. Tests for abnormal TPS resistance. Tests for proper resistance of the TPS circuit. Tests for an open or short-to-ground in TPS signal wire Tests for an open or short-to-ground on 5V reference wire Record the DTC failure record data.

Slowly increase the throttle from idle to full throttle position. Disconnect the TPS connector. Is resistance within the specified value? Reconnect the TPS connector. Using a DVOM, measure resistance between way connector pins 12 and Were any opens, wire-to-wire shorts or shorts-tobattery found?

Disconnect the pin bypass connector on J TCM breakout. Test for opens at pin Were any opens, wire-to-wire shorts, or shorts-toground found?

Is the replacement complete? Operate the vehicle under normal driving conditions. You may have to drive the vehicle in order to experience a fault. DTC P can also be caused by an open in analog return wire A short-to-battery in 5V reference wire or open in analog return wire causes a sensor failed high code for the other devices as well.

Tests for a short-to-battery in TPS signal wire Tests for a short-to-battery in 5V reference wire or open in analog return wire Is the TPS adjusted properly? Fluid is drawn into the oil pump assembly through the suction filter and internal passages in the main housing and front support. The gerotor gear set in the oil pump assembly turns at engine speed and pressurizes the fluid. The main regulator valve regulates the discharge pressure at the oil pump.

Pressurized fluid returns to the hydraulic control module where it is directed to the clutch apply circuits and the control main regulator valve. Control main pressure is used to stroke solenoid regulator valves, which apply and release transmission clutches in response to solenoid commands from the Transmission Control Module TCM.

Surplus oil pressure overage at the main regulator valve is relieved into the converter flow circuit. The converter flow circuit routes pressurized fluid to the torque converter via the converter flow valve and the converter regulator valve. Hot fluid leaving the torque converter is routed back through the converter flow valve into cooler lines that run to the transmission oil cooler in the vehicle cooling system. The cooled fluid is returned to the transmission and enters the transmission lubrication circuit.

The lube regulator valve regulates the proper lubrication pressure and directs excess fluid back to the sump. The transmission fluid temperature sensor is part of the internal wiring harness and measures the sump temperature. The components are powered and engine speed is greater than rpm and less than rpm for 5 seconds. Engine is running. TCM defaults to hot mode shift schedule where fourth range is held and TCC is inhibited to increase engine speed and improve cooler flow.

A stuck autoflow valve can cause overheating in retarder-equipped transmissions. Refer to section 8 for general troubleshooting of performance complaints. Tests for proper transmission fluid level and condition. Monitors the status of DTC P Checks for hot fluid causing DTC P Tests for proper resistance value in entire circuit. Tests for wire-to-wire shorts, shorts-to-ground, or an open on wire Tests the resistance value of the internal harness and sump temperature sensor.

Tests the resistance value of the internal sump temperature sensor. Tests to determine source of overheatthe engine or transmission. Tests for proper cooler pressure drop. Tests for stuck stator. Inspects vehicles engine and transmission cooling systems.

Checks TCM. Install temperature gauges for transmission temperature and engine water temperature. Clear the DTCs. Did DTC P return? Does the manual temperature gauge confirm the transmission fluid temperature actually is hot when DTC P is produced? Turn the ignition OFF. The TCM should not be connected to properly perform this test. Is the resistance within the specified value? Were any wiring defects found? Disconnect the way connector at the transmission and install J Transmission Breakout.

Connect only the J Transmission Breakout to the transmission; the vehicle side of the harness should not be connected for this test. Remove the hydraulic control module assembly. Disconnect the sump thermistor from the internal wiring harness. Is resistance within the specified values? Inspect the engine cooling system for the following conditions: Air flow restrictions Air flow blockage System fluid level and condition Debris 2. Inspect the transmission cooling system for the following conditions: Air flow restrictions Air flow blockage System fluid level and condition Damaged cooler lines and hoses Did you find and correct the condition?

Replace the sump thermistor refer to Mechanics Tips. Use temperature gauge readings obtained in Step 4.

Compare engine water temperature to transmission fluid temperature. Did the transmission become hot before the engine?

Install pressure gauges in the To and From cooler lines. Subtract From Cooler from To Cooler pressure to obtain pressure drop across the transmission oil cooler. Is cooler pressure drop within specified values? Check for a possible torque converter stator malfunction. A stuck stator would be indicated by no cool-down in Neutral after stalling the transmission. Refer to appropriate service manual for Stall Test Procedures. Refer to Table 65 for Product Family.

Refer to Table 66 for Product Family. To verify your repair: 1. Drive the vehicle under normal operating conditions.

Watch for significant change in TFT. If the DTC is active while the vehicle is in a forward range, the transmission shifts to neutral, 1st, 3rd, or 5th range. If the shift selector is moved to the forward range, the transmission shifts to neutral, 1st, 3rd, or 5th range. If the shift selector is moved to R Reverse or N Neutral , transmission shifts to neutral. Diagnostic response honors the latched inhibit at the time the DTC is set.

If a latched inhibit is present and the PRNDL is incorrect, the transmission shifts to neutral range. A defective vehicle battery may allow this DTC to set. Vehicle components such as an ignition switch or TCM ignition relay may cause this DTC to set and not be active, this indicates that an intermittent condition may exist in these components. Test Description The numbers below refer to the step numbers on the diagnostic table. Tests for an active DTC after clearing.

Tests vehicle battery per OEM guidelines. Tests vehicle charging system per OEM guidelines. Start the vehicle, if possible. If the DTC is not active, drive the vehicle. Attempt to duplicate the same conditions observed in the failure records.

Is the charging system operating properly? Drive the vehicle under the same conditions that set the DTC. Is recalibration complete? Start the vehicle. Refer to the transmission bill of material or build history to determine the actual TID level of the transmission.

Compare the highest available TID level in the calibration to the actual transmission hardware. The TCM must complete the processing loop within a specific time limit. The TCM will reset if it does not complete two consecutive loops inside a predetermined time interval. Following recovery from the processor reset, the TCM commands the range that resulted after solenoids were commanded OFF.

The TCM resumes normal operation. This feature limits engine torque in lower ranges to protect the transmission from damage during a stall condition.

The TCM identifies the engine as an approved make and model by matching the component ID with the engine configuration message. The test runs for 15 seconds for the first 20 engine starts after the engine is detected on the J communications link.

The engine does not respond to a LRTP torque reduction request message within 20 ignition cycles. This step verifies the engine supports SEM. This step verifies the engine supports LRTP. If a DTC U is present, troubleshoot and resolve before going to the next step. Is a DTC U present? This indicates the engine torque values are above the transmission ratings set in the TCM calibration. If proper TCM calibration is installed, the engine rating is too high for the transmission.

Recalibrate the engine to a lower torque rating. Was one of the above conditions found and resolved? Has the proper software and calibration been installed? The TCM will take action to protect against damage from overheat. Excessive road debris will reduce the effectiveness of the heat sink on the TCM and could cause internal temperature to rise. Inspect the TCM and surrounding area.

Be sure there are no high temperature components such as engine exhaust pipes mounted in the vicinity of the TCM. Shield or relocate the TCM, if possible. Do you find and correct the problem? Monitor TCM internal temperature. Test Description The numbers below refer to step numbers on the diagnostic table. Tests to see if TCM is reading throttle information. Determines what throttle source the vehicle manufacturer intends to use.

Looks for throttle information on the data link. Refer to with the engine or vehicle manufacturer. Otherwise, determine if the vehicle is using an analog or PWM throttle position sensor. Did the vehicle manufacturer intend to communicate throttle position to the TCM over a digital data link?

Press and release the accelerator pedal while watching the Data Bus Viewer. Does accelerator pedal position information on Data Bus Viewer respond as expected to changes in accelerator pedal position? Coordinate with the vehicle or engine manufacturer to determine the cause of loss of throttle information on the data link. Coordinate with the vehicle or engine manufacturer to repair the analog or PWM throttle sensor.

Drive the vehicle. Verify the TCM detects a valid throttle source. The TCM may receive engine coolant temperature input from an analog temperature sensor, or from one of the SAE digital data links. Tests to see if TCM is reading engine coolant information. Determines what engine coolant temperature source the vehicle manufacturer intends to use. Looks for engine coolant temperature information on the data link.

Otherwise, determine if the vehicle is using an analog engine coolant temperature sensor. Did the vehicle manufacturer intend to communicate engine coolant temperature to the TCM over a digital data link? Allow the engine to warm-up and watch the Data Bus Viewer. Does engine coolant temperature information on Data Bus Viewer respond as expected as the engine warms? Coordinate with the vehicle or engine manufacturer to determine the cause of loss of engine coolant temperature information on the data link.

Coordinate with the vehicle or engine manufacturer to repair the analog engine coolant temperature sensor. Verify the TCM detects a valid engine coolant source. HSD1 is continuously ON during normal operation except during brief circuit tests. The shift selector position and hydraulic state of latch valves determines. Manipulating the chassis harness and data link wiring may reveal intermittent shorts to ground, shorts to another circuit, and open circuits causing a DTC.

Out of specification driveline components can damage transmission components and cause some transmission DTCs.

The following wiring and connector issues can cause transmission DTCs: Expanded female terminals in a connector. Use a mating pin or terminal to check for a light drag feel when the mating terminal or pin is inserted and then slowly removed. There should be some slight friction between the matching terminal and pin combination.

Expanded terminals have no feel of drag when the matching pin or terminal is inserted and removed. Broken terminal locks allow the pins or terminals to push back into the connector, resulting in poor connection or pin-to-pin shorts in the connector. Inspect for broken locks and displaced terminals in connections. Never use paper clips or other devices to back probe a connector while doing Allison service work. Poor pin crimps. Pin crimps should be pull-tested by the technician to verify the crimp is secure to the wire.

If the pin crimp is loose, the pin easily moves or even comes off the wire with a slight tug on the terminal by the technician. This situation may not reveal itself as an active DTC but instead may exhibit other symptoms like shift quality issues.

Connector and pin corrosion caused by moisture in connectors. Empty wire locations in connectors must always have a plug to keep moisture from finding a path into the connector. If butt splices will be used,. Never use wire ties inside the transmission, to hold connector components together in the place of a connector lock, or in the place of the correct strain relief components and clips used to fasten harnesses to the vehicle or to retain vehicle connectors unless OEM approved for the location and vehicle component being repaired.

If possible, use the Breakout Box J , appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle. Load-testing any transmission-related circuits with any other electrical devices such as vehicle lamps or relays, especially with the TCM connected to the harness. This creates a leak path for moisture and damages the wire and insulation.

Always use tools that are in good condition. Refer to the Allison Essential Tools list on the Allison Extranet to complete any service procedure listed in an Allison publication. Also see appropriate Service Manuals and Troubleshooting Manuals for service tools information. Test Description 1. Review of general troubleshooting procedures and DTC service tips 2. Check for active DTC. Check internal transmission harness.

Check OEM Harness. Check for other active DTCs. Check TCM. Start the engine and test drive the vehicle. Refer to appropriate transmission service manual and repair or replace the internal transmission harness.

Connect OEM way transmission harness connector to transmission feedthrough connector. Using a DVOM, check for continuity between pins 11 and Does the circuit have continuity? Go to Step 7. Warn personnel to keep clear of the vehicle.

From action requests perform a clutch test for all ranges and a solenoid test for all solenoids. Replace the TCM. Clear any previous DTCs. Verify ignition OFF. Assemble and re-install transmission Components 3.

Reconnect all vehicle harnesses to TCM and transmission. Clear DTCs. The shift selector position and hydraulic state of latch valves determines the range attained. Diagnostic Aids You may have to drive the vehicle in order to experience a fault. This data can be useful in reproducing the failure mode when DTC was set. Inspect the wiring for poor electrical connections at the TCM and transmission connector. Tests for a wire-to-wire short, or short-to-ground in the wire of the OEM chassis harness.

Tests for wiring defects in the transmission internal harness. Attempt to duplicate the same conditions observed in the failure records range attained, temperature, etc. Disconnect the way connector at the TCM. Disconnect the OEM way connector from the transmission.

Inspect the routing of wire in the chassis harness between the TCM and transmission connector. At J TCM Overlay, test for wire-to-wire shorts between pin 11and and all other pins in the way connector, and test for short-to-ground between pin 11 and chassis ground.

Were any wire-to-wire shorts or shorts-to-ground found? Harness and switch repairs performed by Allison Transmission distributors and dealers are not covered by Allison Transmission warranty.

Coordinate with the vehicle OEM to repair or replace the vehicle wiring or switch. Install the transmission way connector to the J Transmission Breakout. Leave the OEMside disconnected. Using a DVOM at J Transmission Overlay, test for wire-to-wire shorts between pin 1 and all other pins in the way connector, and shorts-to-ground between pin 1 and chassis ground.

NOTE: The resistance value between pins 1 and 2, between pins 1 and 7 7-speed models , and between pins 1 and 8 will read normal solenoid resistance. The resistance value between pin 1 and pin 20 TID wire will read 0 Ohms. Were any wire-to-wire shorts, or shorts-to-ground found? Repair or replace the internal wiring harness. The shift selector position and hydraulic state of latch valves determines range attained.

Install J Transmission Breakout at the transmission way connector. Leave the engine OFF. Leave the OEM-side connected. Leave the transmission-side connected. Inspect the routing of wire in the chassis harness between the TCM and the transmission connector. At J TCM Overlay, test for wire-to-wire shorts between pin 11 and all other pins in the way connector.

Were any wire-to-wire shorts found? Verify that the J Transmission Breakout is installed at the transmission way connector and the OEM-side is disconnected. The resistance value between pins 1 and the pin 20 TID wire will read 0 Ohms. Tests the TID circuit in the internal wiring harness.

Tests the TID in the external wiring harness. Disconnect the transmission way connector. Using a digital multimeter DMM , test for continuity 0 Ohms between pin 20 TID wire and pin 1 in the transmission way connector. Reconnect the transmission way connector. Wire will be connected to the following wire in the transmission internal harness: TID. Wire will be connected to the following wire via the transmission internal harness: TID A. Wire will be connected to the following wire via the transmission internal harness: TID B.

See appropriate Installation Schematic installation drawing for wire and pin numbers. Circuit Description The Transmission Control Module TCM can be calibrated to receive a service brake status input from either an analog input wire or the digital data link.

A mechanical switch attached to the brake pedal sends a signal to either the TCM directly or to another electronic controller in the vehicle. When another controller is used, the TCM receives service brake status as a digital message over the vehicles communications data link. TCM inhibits Neutral to Drive shifts for refuse packer. Diagnostic Aids When analog input wires are used, the service brake status input is active when a pressure switch is closed to complete the circuit between wire and signal return wire The code can be caused by: Faulty wiring Faulty connections to the service brake switch A faulty service brake switch Another controller improperly broadcasting service brake status on the data link when the brake switch is not installed or operating A faulty TCM.

Inspect the wiring for poor electrical connections at the TCM and service brake switch. Monitor data link communications using Data Bus Viewer. Tests for status of analog input wire This step determines if service brake status is being communicated by a data link message.

Tests for shorts-to-ground in wire Tests for proper service brake switch function. Disconnect the TCM way connector.

Check for short-to-ground on wire Were any shorts or wiring defects found? Using a DVOM, check for continuity when switch is pressed and no continuity when switch is released. Does the switch close when pressed and open when released? Connect the way connector, if removed in Step 6. NOTE: Allison Transmission is not responsible for data link messages that originate in other transmission controllers.

Repairs not associated with the transmission controller are not covered by Allison Transmission warranty. Coordinate with the vehicle or engine OEM to correct the cause of the inconsistent service brake switch status message. Circuit Description The and Product Family transmission control module TCM can receive input from a strip-type shift selector. This type of shift selector communicates with the TCM via 4-bit parallel data wires.

The TCM interprets each particular combination of switch states into a specific range selection, i. Tests for the proper function of the strip shift selector.

Tests for wiring defects in the OEM wiring harness. Refer to Strip Shift 1. Data Table 61 3. Turn ON ignition. Leave engine OFF. Note if any wire is not in the proper switch state.

Disconnect the strip shift selector. Physically inspect the wiring between the striptype shift selector and the TCM. DTC PC can be caused by an open or short-to-ground in either the 5V reference wire or transmission fluid level signal wire An open or short-to-ground in the common 5V reference wire causes a Sensor Failed Low code for the other devices as well. Tests for proper transmission fluid level. Tests for opens or short-to-ground on wire It may also indicate an open or short-toground in either the 5V reference wire or OLS signal wire Disconnect the external wiring harness from the way transmission connector.

Test for opens and shorts-to-ground on wire Leave the TCM-side disconnected. Connect the way connector. Verify the transmission way connector is disconnected.

Inspect the transmission way connector pins 15, 16, and 19 for loose or out-of-position terminals. Refer to appropriate transmission service manual and remove the control module from the transmission.

Remove OLS from channel plate. Connect the external harness at the way connector. Leave the ignition OFF. Inspect internal wiring harness wires , , and Test for opens and shorts-to-ground in wires and in the internal wiring harness.

Were there any wiring defects? DTC PD can also be caused by an open in the analog return wire A short-to-battery on the 5V reference wire or an open in the analog return wire causes a Sensor Failed High code for the other devices as well.

Look for the following conditions: A bent terminal A backed-out terminal A damaged terminal Poor terminal tension A chafed wire A broken wire inside the insulation Copyright Allison Transmission, Inc. Tests for shorts-to-battery on wire and open on wire Tests for shorts-to-battery on wire Tests for loose or out-of-position terminals in way connector. Tests OLS functionality. Tests for a defective internal wiring harness. It may also indicate a short-to-battery in either the 5V reference wire or OLS signal wire , or an open in the analog return wire Test for shorts-to-battery and pin-to-pin shorts on wire Test for an open in wire Test for shorts-to-battery and pin-to-pin shorts in wire Reconnect the TCM way connector.

Were any loose or out-of-position terminals found? Reconnect the external harness at the way connector. Test for pin-to-pin shorts in wire and or opens in wire in the internal wiring harness. Reinstall the control module to the transmission if removed in Step Is the reinstallation complete? The TFT sensor is a thermistor that changes its resistance value based on the temperature of the transmission fluid.

The TCM uses this information to control shift quality. A valid startup temperature is detected. The TCM detects a temperature change that is under a calibration limit when compared to samples of the minimum and maximum temperature values. TCM uses calibration default for temperature values. Diagnostic Aids Review Appendix A for diagnosing intermittent electrical fault conditions. This step verifies which condition has set the DTC P Tests for wire-to-wire shorts, shorts-to-ground, or an open condition on wire Tests for proper system circuit resistance value.

Tests the resistance value of the internal harness and TFT sensor. Tests the resistance value of the internal TFT sensor. Record the failure record. An unrealistic transmission temperature change of greater than 1. Did either of the fail conditions occur? Disconnect the transmission way connector, if it was not disconnected in Step 4.

Connect the transmission way connector. Measure resistance between pin 54 and pin Connect only the J Transmission Breakout to the transmission.

The vehicle side of the harness should not be connected for this test. Measure resistance between pin 18 and pin 19 in transmission way connector. Watch for significant changes in TFT. When engine coolant temperature sensor is present, engine is running. Turn OFF the engine. Measure resistance between pin 54 to pin Replace the sump thermistor refer to appropriate Mechanics Tips. DTC code P may also be caused by an open in wire or Review Appendix A for diagnosing intermittent electrical fault conditions.

Look for the following conditions: A bent terminal A backed-out terminal A damaged terminal Poor terminal tension A chafed wire A broken wire inside the insulation Verifies which condition has set the DTC P Tests for wiring defects in external harness.

Disconnect the engine coolant temperature sensor and retarder temperature sensor. Also test for wire-to-wire shorts or shorts-tobattery on wire , wire , or wire Connect the J Transmission Breakout to the transmission only. Refer to 3. Each sensor consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet.

These elements are contained in a housing that is mounted adjacent to a rotating ferrous member. Two signal wires extend from one end of the housing and an exposed end of the pole piece is at the opposite end of the housing. The permanent magnet produces lines of flux around the pole piece. The signal wires from the sensor are formed as twisted pairs to cancel magnetically induced fields. Using two-wire differential input at the TCM eliminates noise from other sources.

Failure is set if an unrealistic change in transmission turbine speed is detected at or above rpm for 0. Noisy turbine speed. Noise is determined with two counters. A low counter is incremented when turbine speed change is below rpm for 2. A high counter is incremented when turbine speed change is above rpm. Allison Series Troubleshooting Manual. Allison Transmission , series fault code list. Allison Transmission DOC 7.

Allison Transmission Fault Codes Manual. Allison Transmission Troubleshooting. Marvin Friday, 27 September I would appreciate any information as to why this is happening. Randy wrongwayrandy msn.

Allison WT Transmission Troubleshooting Diagnostic Trouble Codes Service Manual | eBay

Okay, finally going to start my own thread on this insert your favorite curse here. I found that there was a short somewhere in the wire from the DDEC2 to the speed sensor. I have replaced that wire but have not been able to get the ECU to 'let go' of the error. I also can not get an error code out of the ECU it just beeps continuously no matter what position I put the Transmission Test switch in. Background: Problem started when I was going to get tires. I changed out the speed sensor, thinking that was it.

The problem went away for a few days, then came back after hitting a bump on the way home. One bump would cause the error, another would make it go away. When the error is active I do not have a functioning speedometer either. The resistance was pretty much nothing. According to the troubleshooting guide, the fix is to run a new twisted pair. I think I boo-booed this though as I connected D ground?

The Transmission still beeped like a fonkin baby bird. Maybe that is just the ground? D goes to the check engine, so, yeah, probably need to reconnect that. Not sure what to do with D though, it is a 12V black wire so ground it? It seems like you should start by testing the wires running between the speed sensor and Allison ECU J1 connector, which as far as I know, you would do after disconnecting the speed sensor connector and the J1 and J2 connectors on the Allison ECU.

I think wire also goes to the speedometer so maybe that could throw you off too. I don't think the wires from the speed sensor go directly to the DDEC, I'm thinking you may be troubleshooting a different speed sensor set up than what you have but I'm not sure.

That is what I thought first too. I mean I'm grasping at straws, so tomorrow I'll head out and check the J1 connector. I have the ECU sitting on the bench at the moment. I'm going to take it down to the local Allison shop tomorrow and see if they can verify that there are no codes recorded. The Trans ECU hasn't given me an error code to work with. In my haste though I misidentified D so I'll be starting over again tomorrow.

If the transmission would give me an error code I could troubleshoot from there. And the Transmission troubleshooting guide for electronic controlled transmissions seems to imply that the DDEC provides the speed to the ECU through the CAB harness interface or the "Cigar Adaptor" which I haven't seen yet does it actually look like a cigar?

Okay scratch my last two posts. So it is possible that the DDEC error was downstream of the problem. So tomorrow - undo the changes that I made today.

Take the ECU to the Allison shop to have it tested since it is out. Test the wires from 1L and 1M to the speed sensor. The problem is likely in there somewhere. If not my insanity will keep me company while I try to think of something. Bulkhead connector,did you say bulkhead connector? I know you have checked it,twice,right? Yes the dreaded Darth Bulkhead Connectors. If it weren't for the giant capacitors right in front of them they would be easy to check as a bulkhead connector should be.

I'll clean and check them again. Last pass through them I didn't see any problems, all the pins were bright and shiney and the connectors were dry to the touch. I still have not found the "Cigar Adaptor", about how big is it?

I checked the connectors to the shifter plate and they are all clean and tight. I'm taking the ECU down to International today to have them run a diagnostic on it if they can. The transmission troubleshooting guide did have Failed ECU as one of the possible causes and with no error code - who knows. BTW- if sometimes I come across a bit flaky, well it is because I am.

A few too many head injuries, you know they add up. So I thank you all for putting up with my odd sense of humor and stream of consciousness writing style. Just ran into this the other day. Does anyone know what that capacitor it for? I think I'll permanently move it after seeing how many issues there are with these bulkhead connectors.

I was working on a cruise control issue on a WB,we checked the bulkhead connectors,the owner looked at the pins,i looked at the pins,we looked twice,each of us. The third time we looked we found the burned pin,its hard to see those little pins,even using a good flashlight. Hey,with a description like that you should be able to find it in the dark! I was really thinking of photoshopping something up for you. You finally put your glasses on for the third time? Well today was good. I went through all the bulkhead connectors I temporarily moved the giant capacitors - cleaned and inspected each then reinstalled.

For a min I had a panic as I had 4 connectors off and was like - did this one go there? But it all worked out and now they are labeled. I did the 5 by the big capacitors and then did the other ones in front for good measure. I did find the Cigar Tube but was a little disappointed in it. I cleaned and reinstalled the connectors on it too. They said that they can't test or read codes off the ECU without the rest of the bus attached. I mean, it is what it is, but boy I hope Allison figured out that being able to mail an ECU in for testing is way easier than mailing a lbs bus to them.

So I just crossed my fingers and hoped that the ECU was okay. Cleaned all the pins with a dental scaler then reinstalled the ECU. Reading through the troubleshooting manual, in the very back, section it has one page on troubleshooting with no codes. These stuck out to me: - Oil Level : Good - Batteries : Meh - 6 yr old engine batteries - replaced them one had a bad cell on testing I was already checking the connections, so I checked the fluid and batteries.

It was probably time to replace them anyhow and that could cause the intermittent problem. So since I could, I replaced them with new batteries. I also noted that after changing the engine batteries out the K12 Delay Relay stopped making noises. Test start, no error and no codes.

Just ran out of daylight. I got nothing Call if you need me tomorrow,i can come tow you home with my pickup! Just back from a 50 mile test drive dang, I could have visited Randy with no problems. So the fix was either batteries, bulkhead connectors, ECU connectors, or the old out of shape speed sensor plug.

Your guess is as good as mine. I just know that if I have to that I can repeat the process on the road if need be. Any suggestions on how to better clean the pins in the connectors? I did it with a dental scaler thing, but there might be a better way? It is located on the passenger side near the heater core.

Allison trans troubleshooting guide

Allison trans troubleshooting guide