Allison

Allison 1000 & 2000 Gen 5 Fault Code:P0880 TCM Power Input Signal

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CIRCUIT DESCRIPTION:
The TCM requires a switched ignition voltage input and a direct battery voltage input. Battery direct voltage is supplied to pins 10 and 70 at the 80-way connector. DTC P0880 sets during the next ignition cycle if battery power is lost before the power down process is complete and the engine is running.

ACTION TAKEN WHEN THE DTC SETS:
When the DTC P0880 is active, the following conditions occur:
1. The CHECK TRANS light is not illuminated (non-OBD II strategy).
2. The DTC is stored in TCM history.
3. The TCM loses adaptive information for the drive cycle.
4. TCM reverts to previous adaptive settings.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTC’s, function, or shift quality concern:

1.Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. 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. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension
5. A chafed wire.
6. A broken wire inside the insulation.

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.


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Allison 1000 & 2000 Gen 5 Fault Code:P0881 TCM Power Input Signal – Performance

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CIRCUIT DESCRIPTION:
The TCM requires input battery voltage which originates direct from the vehicle battery and runs through a 10 amp fuse to TCM pins 10 (wire 110) and 70 (wire 170).

DTC P0881 sets when the TCM detects the following:
1. Large variations in battery direct voltage.
2. When there is a battery direct voltage variation of a calibrated voltage detected for a calibrated time, a fault pending is reported. After a calibrated time a DTC is set with a failure response (voltage variation is determined from minimum and maximum ignition voltage values).

ACTION TAKEN WHEN THE DTC SETS:
1. Hydraulic default is commanded. Shift selector position and hydraulic state of logic valves determine range.
2. The CHECK TRANS light does not illuminate.
3. The TCM forces Variable Modulated Main off.
4. The TCM inhibits Torque Converter Clutch (TCC) engagement.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. 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. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. You may have to drive the vehicle in order to experience a fault. The diagnostic tool can be used to record a snapshot for later review. Battery direct input is a viewable option in the diagnostic tool. Using the diagnostic tool, monitor for erratic voltage that may indicate a wiring concern.

5. This DTC indicates a variation in battery direct voltage. Vehicle accessories imposing a large load on the battery circuit could also cause the DTC to set. Other possibilities include loose or corroded battery cables, or an internal TCM failure caused by a burn up circuit trace could allow this DTC to set.

6. Vehicle charging system failure may cause this DTC under certain circumstances.

7. This DTC may indicate that an internal voltage problem has occurred inside the TCM. The use of a substitute TCM would be a good way to diagnose this problem.

8. A defective vehicle battery may induce this DTC.

Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension
5. A chafed wire.
6. A broken wire inside the insulation.

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.


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Allison 1000 & 2000 Gen 5 Fault Code:P0882 TCM Power Input Signal – Low

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CIRCUIT DESCRIPTION:
The TCM requires input battery voltage which originates direct from the vehicle battery and runs through a 10 amp fuse to TCM pins 10 (wire 110) and 70 (wire 170).

DTC P0882 sets when the TCM detects the following:
Battery direct voltage is detected below 9 volts for a calibrated time.

ACTION TAKEN WHEN THE DTC SETS:
1. Hydraulic default is commanded. Shift selector position and hydraulic state of logic valves determine range.
2. The CHECK TRANS light illuminates (non-OBD II strategy).
3. The TCM forces Variable Modulated Main off.
4. The TCM inhibits Torque Converter Clutch (TCC) engagement.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. 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. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. Vehicle charging system failure may cause this DTC to set under certain circumstances

5. A defective vehicle battery may induce this DTC. Test the vehicle battery to verify proper voltage and load capacity.

Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension
5. A chafed wire.
6. A broken wire inside the insulation.

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.


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Allison 1000 & 2000 Gen 5 Fault Code:P0883 TCM Power Input Signal – High

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CIRCUIT DESCRIPTION:
The TCM requires input battery voltage which originates direct from the vehicle battery and runs through a 10 amp fuse to TCM pins 10 (wire 110) and 70 (wire 170).

DTC P0883 sets when the TCM detects the following:
12V TCM – Battery direct voltage is above 16 volts for a calibrated time.
24V TCM – Battery direct voltage is above 32 volts for a calibrated time.

ACTION TAKEN WHEN THE DTC SETS:
1. Hydraulic default is commanded. Shift selector position and hydraulic state of logic valves determine range.
2. The CHECK TRANS light illuminates (non-OBD II strategy).
3. The TCM forces Variable Modulated Main off.
4. The TCM inhibits Torque Converter Clutch (TCC) engagement.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. 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. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. This DTC normally sets due to vehicle charging system concerns. Verify the concern and contact OEM for further repair details.

NOTE: OEM does not warranty charging system concerns.

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Allison 1000 & 2000 Gen 5 Fault Code:P088B Transmission Filter Very Deteriorated

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CIRCUIT DESCRIPTION:
Filter Life Monitor (FM) is a part of OEM 5th Generation Prognostics functionality. When enabled in the TCM, prognostic logic determines control main filter life based on hours accumulated and vehicle mileage. This information is used to determine the remaining control main filter useable life. When the TCM determines the filter life has degraded, a J1939 message is sent to a dash mounted SERVICE TRANS indicator lamp. A flashing SERVICE TRANS indicator lamp informs the driver that the transmission control main filter should be serviced. If the SERVICE TRANS indicator lamp is ignored for 100 hours, a CHECK TRANS light illuminates and DTC P088B sets.

ACTION TAKEN WHEN THE DTC SETS:
1. The CHECK TRANS light is illuminated.
2. The TCM forces Variable Modulated Main off.
3. DTC P088B is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:
Replace the Control Main Filter. Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

DIAGNOSTIC AIDS:
This function can also be reset by turning on the ignition and selecting N (Neutral)-R (Reverse )-N (Neutral)-R (Reverse)-N (Neutral)-D (Drive)-N (Neutral).

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Allison 1000 & 2000 Gen 5 Fault Code:P0897 Transmission Fluid Deteriorated

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CIRCUIT DESCRIPTION:
Oil Life Monitor (OM) is a part of OEM 5th Generation Prognostics functionality. When enabled in the TCM, prognostic logic determines vehicle duty cycles based on shifts per mile, transmission revolutions, and hours accumulated. This information determines the proper oil change intervals. When the TCM determines the oil has degraded, a J1939 message is sent to a dash mounted SERVICE TRANS indicator lamp, informing the driver the transmission oil should be serviced. If the SERVICE TRANS indicator lamp is ignored for a calibrated period, a CHECK TRANS light illuminates and DTC P0897 sets.

ACTION TAKEN WHEN THE DTC SETS:
1. The CHECK TRANS light illuminates.
2. DTC is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The OEM function can also be reset by turning on the ignition and selecting N (Neutral)-D (Drive )-N (Neutral)-D (Drive )-N (Neutral)-R (Reverse )-N (Neutral).

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Allison 1000 & 2000 Gen 5 Fault Code:P0960 Main Pressure Modulation Solenoid Control Circuit Open

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CIRCUIT DESCRIPTION:
Pressure Control Solenoid (MAIN MOD) is a Normally Closed (N/C) solenoid used to modulate the transmission main pressure schedule. The TCM commands the solenoid ON when specific transmission and engine conditions are met. When MAIN MOD is commanded on, pressure is routed to the main regulator valve lowering the main pressure schedule.

The TCM sends control current to MAIN MOD from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously on unless the TCM detects a fault condition. The TCM regulates the amount of current to MAIN MOD by switching MAIN MOD’s low side driver on and off. Wire 174 completes the circuit between MAIN MOD and its low side driver. DTC P0960 indicates that the TCM processor has detected an open condition in MAIN MOD’s electrical circuit. The open condition may exist in the high side (wire 111) or low side (wire 174).

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0960 is active, the following conditions occur:
1. The CHECK TRANS light illuminates (non-OBD II strategy).
2. The TCM forces Variable Modulated Main off.
3. The DTC is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. 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. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. DTC P0960 indicates an open in the electrical circuit for the MAIN MOD. In addition to MAIN MOD, HSD1 also supplies power to PCS1 and TCC. If DTC P0960 is accompanied by DTC P2727 (PCS1 open circuit) and/or DTC P2761 (TCC open circuit), the open is most likely in the high side of the circuit.

5. You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This data can be useful in reproducing the failure mode when the DTC was set.

Inspect the wiring for poor electrical connections at the TCM and the transmission main connector. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension
5. A chafed wire.
6. A broken wire inside the insulation.

Inspect OEM wiring harness routing. Look for possible contact points where chafing could occur leading to an open circuit condition. Moving parts on the vehicle could be contacting the harness; this includes parking brake drum, suspension components, etc.

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

If the DTC appears to be temperature related, suspect a defective Main Mod Pressure Control Solenoid. It is possible for a solenoid to be temperature sensitive causing resistance values to fluctuate. This may cause an intermittent DTC to be set.

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Allison 1000 & 2000 Gen 5 Fault Code:P0961 Main Pressure Modulation Solenoid System Performance

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CIRCUIT DESCRIPTION:
Main Pressure Modulation Solenoid is a normally closed solenoid that regulates main pressure to allow for decreased engine loading. The intent of this code is to ensure that the Main Pressure Modulation Solenoid defaults to full pressure if a clutch slip event occur. This response is designed to help protect the transmission from internal clutch damage due to low main pressure. DTC P0961 sets when the Main Pressure Modulation Solenoid is on and the number of slip events for a range is equal to or greater than a calibrated number of counts, and gear slip is indicated.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0961 is active, the following conditions occur:
1. The CHECK TRANS light illuminates (non-OBD II strategy).
2. Variable Modulated Main pressure is disabled, allowing full main pressure to be implemented.
3. The DTC is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
1. You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to determine transmission range and/or certain vehicle operating variables such as temperature, run time, etc. This data can be useful in reproducing the failure mode when the DTC was set.
2. Do not run the vehicle for extended periods of time with this DTC active or transmission overheating may occur.
3. If the transmission has had the transmission fluid changed, is low, or had the Control Module removed and replaced, this DTC can be set. Clear code. Check for proper transmission fluid level and verify that the code returns.
4. This DTC could indicate a cut clutch seal, damaged clutch, or defective main modulation solenoid.
5. Incorrect ratio codes typically indicate mechanical problems with specific clutches for range indicated; for example, C1 and C5 for 1st range.
6. An incorrect ratio DTC may indicate a mechanically failed clutch.
7. Output or turbine tone wheel damage may cause erratic speed sensor input allowing this DTC to set.

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Allison 1000 & 2000 Gen 5 Fault Code:P0962 Main Pressure Modulation Solenoid Control Circuit Low

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CIRCUIT DESCRIPTION:
Pressure Control Solenoid (MAIN MOD) is a Normally Closed (N/C) solenoid used to modulate the transmission main pressure schedule. The TCM commands the solenoid ON when specific transmission and engine conditions are met. When MAIN MOD is commanded on, pressure is routed to the main regulator valve lowering the main pressure schedule.

The TCM sends control current to MAIN MOD from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously on unless the TCM detects a fault condition. The TCM regulates the amount of current to MAIN MOD by switching MAIN MOD’s low side driver on and off. Wire 174 completes the circuit between MAIN MOD and its low side driver. DTC P0962 indicates that the TCM processor has detected an open condition in MAIN MOD’s electrical circuit.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0962 is active, the following conditions occur:
1. The CHECK TRANS light illuminates (non-OBD II strategy).
2. The DTC is stored in the TCM history.
3. The TCM forces Variable Modulated Main off.
4. The TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. 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. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. DTC P0962 indicates a short-to-ground in the electrical circuit for the MAIN MOD solenoid.

5. You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This data can be useful in reproducing the failure mode when the DTC was set.

Inspect the wiring for poor electrical connections at the TCM and the transmission main connector. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension
5. A chafed wire.
6. A broken wire inside the insulation.

Inspect OEM wiring harness routing. Look for possible contact points where chafing could occur leading to an open circuit condition. Moving parts on the vehicle could be contacting the harness; this includes parking brake drum, suspension components, etc.

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

If the DTC appears to be temperature related, suspect a defective MAIN MOD. It is possible for a solenoid to be temperature sensitive causing resistance values to fluctuate. This may cause an intermittent DTC to be set.

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Allison 1000 & 2000 Gen 5 Fault Code:P0963 Main Pressure Modulation Solenoid Circuit High

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CIRCUIT DESCRIPTION:
Pressure Control Solenoid (MAIN MOD) is a Normally Closed (N/C) solenoid used to modulate the transmission main pressure schedule. The TCM commands the solenoid ON when specific transmission and engine conditions are met. When MAIN MOD is commanded on, pressure is routed to the main regulator valve lowering the main pressure schedule.

The TCM sends control current to MAIN MOD from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously on unless the TCM detects a fault condition. The TCM regulates the amount of current to MAIN MOD by switching MAIN MOD’s low side driver on and off. Wire 174 completes the circuit between MAIN MOD and its low side driver. DTC P0963 indicates that the TCM processor has detected a short-to-battery condition in the low side of solenoid MAIN MOD’s electrical circuit.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0963 is active, the following conditions occur:
1. The CHECK TRANS light illuminates (non-OBD II strategy).
2. The TCM forces Variable Modulated Main off.
3. The DTC is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. 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. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. DTC P0963 indicates a short-to-battery in the electrical circuit for the MAIN MOD solenoid.

5. You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to determine transmission range and/or certain vehicle operating variables such as temperature, run time etc. This data can be useful in reproducing the failure mode when the DTC was set.

Inspect the wiring for poor electrical connections at the TCM and the transmission main connector. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension
5. A chafed wire.
6. A broken wire inside the insulation.

Inspect OEM wiring harness routing. Look for possible contact points where chafing could occur leading to an open circuit condition. Moving parts on the vehicle could be contacting the harness; this includes parking brake drum, suspension components, etc.

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

If the DTC appears to be temperature related, suspect a defective MAIN MOD solenoid. It is possible for a solenoid to be temperature sensitive causing resistance values to fluctuate. This may cause an intermittent DTC to be set.

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