Allison

DIAGNOSTIC RESPONSE:
DNS, Lock in Neutral

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses input from the turbine speed and output speed sensors to determine the current commanded for steady-state gear ratio. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. No shift in progress.
3. Hydraulic default condition not present.
4. Output speed is above 200 rpm.
5. Engine initialization or shutdown is not in process.

CONDITIONS FOR SETTING THE DTC:
DTC P0736 sets during steady-state condition when the calculated reverse (R1) gear ratio differs from the known reverse (R1) gear ratio for more than 2 seconds.

ACITON TAKEN WHEN THE DTC SETS
When DTC P0736 is active, the following conditions will occur:
1. Locks in Neutral (N).
2. While diagnostic response is active, the TCM ignores shift selector inputs.
3. The CHECK TRANS light illuminates.
4. DTC is stored in the TCM history.
5. TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/TRANS CHECK LIGHT
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:
NOTE: This DTC requires Clutch Test using the diagnostic tool to detect clutch slip during a partial stall and also to pressurize clutches for measurement without needing to drive the vehicle. Note that main pressure and clutch pressures are reduced when the Main Mod Solenoid is energized. Low commanded Main Mod solenoid pressures shown in Data Monitor correlate to reduced main pressure and clutch pressures. Main pressure is reduced by Main Mod in N (Neutral), 1 (First Range), and 2 (Second Range) when engine speed is below 1500 rpm. Higher Main Mod commanded pressures correlate to no reduction in main pressure and clutch pressures. Refer to First Steps and Tips for Troubleshooting and the OEM Technician’s Library for more information about the action requests for Clutch Test, Full Main Pressure Test, and also the procedure for Stall Testing.

DTC P0736 may be caused by:
1. Output speed sensor signal circuit issues.
2. Turbine speed sensor signal circuit issues.
3. Low clutch pressures, main pressure, or control main pressure.
4. Control module issues like stuck/sticky valves, mechanically defective solenoids, broken springs, damaged valve bores, plugged suction filter, damaged gaskets, excessive leaks to exhaust, etc.
5. Transmission issues such as damaged output speed sensor wheel slot, worn and/or damaged seals or seal rings, dislocated snap rings, worn clutch packs, rotating drum damage (affecting turbine speed pickup), debris, excessive hydraulic circuit leaks to exhaust or other hydraulic circuits.

NOTE: Damage to the output speed sensor wheel slot is an indication the driveline does not meet ATI specifications. Correct all driveline issues before putting transmission back in service.

6. Clutch system issues causing a clutch not to release.
7. Issue with TCM.

DIAGNOSTIC RESPONSE:
None

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses data received from the engine speed sensor and the turbine speed sensor to calculate torque converter slip value. The TCM then compares this calculated slip value to a preset value in the TCM calibration.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. Hydraulic default condition not present.
3. Engine initialization or shutdown is not in process.
4. Selected range is a forward range.
5. Throttle position is 50% or more.
6. Transmission fluid temperature is between 25°C (77°F) and 130°C (266°F).
7. Six or more seconds have elapsed since Torque Converter Clutch (TCC) was applied in a range.

CONDITIONS FOR SETTING THE DTC:
DTC P0741 sets when the TCM detects a TCC slip value greater than 150 rpm for more than 15 seconds, indicating TCC did not apply.

ACTION TAKEN WHEN THE DTC SETS:
1. DTC is stored in TCM history.
2. The CHECK TRANS light illuminates.
3. TCC (lockup clutch) commanded off.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
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:
DTC PO741 may be caused by:
1 Turbine speed sensor signal circuit issues.
2. Low TCC pressure and/or main pressure.
3. Control module issues like stuck/sticky valves, mechanically defective TCC solenoid, broken springs, damaged valve bores, plugged suction filter, damaged gaskets, excessive leaks to exhaust, etc.
4. Transmission issues such as worn and/or damaged seals or seal rings, worn TCC damper, mechanical TCC issues, rotating drum damage (affecting turbine speed pickup), debris, excessive hydraulic circuit leaks to exhaust or other hydraulic circuits.
5. Issue with TCM.

DIAGNOSTIC RESPONSE:
DNS

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses data received from the engine speed sensor and the turbine speed sensor to calculate torque converter slip value. The TCM then compares this calculated slip value to a preset value in the TCM calibration.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. Hydraulic default condition not present.
3. Number of drive cycles more than 10 since last test.
4. Neutral or Neutral Very Low (NVL) attained.
5. C5 clutch pressure command not changing.
6. Output speed less than 50 rpm when throttle position is less than 15%.
7. Engine speed less than 450 rpm when torque converter slip is less than 125 rpm.
8. Previous drive cycle turbine speed is less than 200 rpm in range.

CONDITIONS FOR SETTING THE DTC:
If conditions are met for running the DTC, this test commands the Pressure Control Solenoid 1 (PCS 1) to pressurize while the vehicle is stopped in Neutral Very Low (NVL) in order to determine if C1 latch valve is stuck in a stroked position. If C1 latch is stuck stroked, C1 clutch will pressurize causing the turbine shaft to lock with the output shaft in NVL and the DTC becomes active.

ACTION TAKEN WHEN THE DTC SETS:
1. DTC is stored in TCM history.
2. The CHECK TRANS light illuminates.
3. Range limited to Neutral (N), Reverse (R), and 2nd through 4th range.

CONDITIONS FOR CLEARING
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:
NOTE: C1 latch valve does not have a solenoid located in the valve bore. C2 latch valve has Shift Solenoid 1 (SS1) located in the valve bore. This test determines if C1 latch valve is stuck.

DTC P0752 may be caused by:
1. Stuck C1 latch valve.
2. Issue with SS1.
3. Issue with TCM.

DIAGNOSTIC RESPONSE:
DNS, RPR

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses input from the turbine speed and output speed sensors to determine the current commanded for steady-state gear ratio. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

This DTC test determines if the on-coming clutch controlled by Pressure Control Solenoid 2 (PCS2) engages during a forward range shift. PCS2 controls the C2 clutch for 4th through 5th gears and C3 clutch for Reverse or Reverse 2. PCS2 also controls C3 clutch in the 3700 model for Low range.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. Hydraulic default condition not present.
3. Output speed is above 125 rpm.
4. Turbine speed above 60 rpm.
5. Engine initialization or shutdown is not in process.

CONDITIONS FOR SETTING THE DTC:
DTC P0776 sets when the TCM detects the on-coming clutch did not maintain engagement after 2 seconds during the range shifts that require PCS2 to control either C2 or C3 clutch.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0776 is active, the following conditions will occur:
1. If DTC goes active while making a forward range shift (e.g., 1-2), the transmission returns to the previous range. If DTC goes active during a shift to reverse or neutral, the transmission shifts to neutral. Once shifting is complete, the attained range is locked in range.
2. While diagnostic response is active, the TCM ignores shift selector inputs.
3. The CHECK TRANS light illuminates.
4. DTC is stored in the TCM history.
5. TCM inhibits TCC engagement.
6. TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
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:
NOTE: This DTC requires Clutch Test using the diagnostic tool to detect clutch slip during a partial stall and also to pressurize clutches for measurement without needing to drive the vehicle. Note that main pressure and clutch pressures are reduced when the Main Mod Solenoid is energized. Low commanded Main Mod solenoid pressures shown in Data Monitor correlate to reduced main pressure and clutch pressures. Main pressure is reduced by Main Mod in N (Neutral), 1 (First Range), and 2 (Second Range) when engine speed is below 1500 rpm. Higher Main Mod commanded pressures correlate to no reduction in main pressure and clutch pressures. Refer to First Steps and Troubleshooting and the OEM Technician’s Library for more information about the action requests for Clutch Test, Full Main Pressure Test, and also the procedure for Stall Testing.

DTC P0776 may be caused by:
1. Output speed sensor signal circuit issues.
2. Turbine speed sensor signal circuit issues.
3. Low clutch pressures, main pressure, or control main pressure.
4. Control module issues like stuck/sticky valves, mechanically defective solenoids, broken springs, damaged valve bores, plugged suction filter, damaged gaskets, excessive leaks to exhaust, etc.
5. Transmission issues such as damaged output speed sensor wheel slot, worn and/or damaged seals or seal rings, dislocated snap rings, worn clutch packs, rotating drum damage (affecting turbine speed pickup), debris, excessive hydraulic circuit leaks to exhaust or other hydraulic circuits.

NOTE: Damage to the output speed sensor wheel slot is an indication the driveline does not meet ATI specifications. Correct all driveline issues before putting transmission back in service.

6. Issue with TCM.
7. A high resistance circuit in Shift Solenoid 1 (SS1) low side solenoid wire (W151) may cause this code. There may be a P0973 in history with this code. SS1 strokes the C2 latch valve when energized. A high resistance connection may not fully energize the SS1 in order to stroke the C2 latch. Check for expanded terminals, broken/loose connectors, loose pin crimps, or damaged W151 in chassis harness. Check condition of wire harness in control valve module and the SS1 resistance if needed.
8. PCS2 controls either the C2 or C3 clutch. However, this code may also occur when any other clutch did not maintain engagement while PCS2 is commanded.

DIAGNOSTIC RESPONSE:
DNS, RPR

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses input from the turbine speed and output speed sensors to determine the current commanded for steady-state gear ratio. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

This DTC test determines if the off-going clutch controlled by Pressure Control Solenoid 2 (PCS2) remains engaged during a forward range shift. PCS2 controls the C2 clutch for 4th through 5th gears and C3 clutch for Reverse or Reverse 2. PCS2 also controls C3 clutch in the 3700 model for Low range.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. Hydraulic default condition not present.
3. Output speed is 200 rpm or higher.
4. Turbine speed is 200 rpm or higher.
5. Engine initialization or shutdown is not in process.

CONDITIONS FOR SETTING THE DTC:
DTC P0777 sets when the TCM detects the off-going clutch did not fully release after 2 seconds during the range shifts that require PCS2 to control either C2 or C3 clutch.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0777 is active, the following conditions will occur:
1. If DTC goes active while making a forward range shift (e.g., 1-2), the transmission returns to the previous range. If DTC goes active during a shift to reverse or neutral, the transmission shifts to neutral. Once shifting is complete, the attained range is locked in range.
2. While diagnostic response is active, the TCM ignores shift selector inputs.
3. The CHECK TRANS light illuminates.
4. DTC is stored in the TCM history.
5. TCM inhibits TCC engagement.
6. TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
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:
NOTE: This DTC requires Clutch Test using the diagnostic tool to detect clutch slip during a partial stall and also to pressurize clutches for measurement without needing to drive the vehicle. Note that main pressure and clutch pressures are reduced when the Main Mod Solenoid is energized. Low commanded Main Mod solenoid pressures shown in Data Monitor correlate to reduced main pressure and clutch pressures. Main pressure is reduced by Main Mod in N (Neutral), 1 (First Range), and 2 (Second Range) when engine speed is below 1500 rpm. Higher Main Mod commanded pressures correlate to no reduction in main pressure and clutch pressures. Refer to First Steps and Troubleshooting and the OEM Technician’s Library for more information about the action requests for Clutch Test, Full Main Pressure Test, and also the procedure for Stall Testing.

DTC P0777 may be caused by:
1. Output speed sensor signal circuit issues.
2. Turbine speed sensor signal circuit issues.
3. Low clutch pressures, main pressure, or control main pressure.
4. Control module issues like stuck/sticky valves, mechanically defective solenoids, broken springs, damaged valve bores, plugged suction filter, damaged gaskets, excessive leaks to exhaust, etc.
5. Transmission issues such as damaged output speed sensor wheel slot, worn and/or damaged seals or seal rings, dislocated snap rings, worn clutch packs, rotating drum damage (affecting turbine speed pickup), debris, excessive hydraulic circuit leaks to exhaust or other hydraulic circuits.

NOTE: Damage to the output speed sensor wheel slot is an indication the driveline does not meet ATI specifications. Correct all driveline issues before putting transmission back in service.

6. Issue with TCM.
7. A high resistance circuit in Shift Solenoid 1 (SS1) low side solenoid wire (W151) may cause this code. There may be a P0973 in history with this code. SS1 strokes the C2 latch valve when energized. A high resistance connection may not fully energize the SS1 in order to stroke the C2 latch. Check for expanded terminals, broken/loose connectors, loose pin crimps, or damaged W151 in chassis harness. Check condition of wire harness in control valve module and the SS1 resistance if needed.
8. PCS2 controls either the C2 or C3 clutch. However, this code may also occur when any other clutch did not maintain engagement while PCS2 is commanded.

DIAGNOSTIC RESPONSE:
DNS, Lock in Neutral

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses input from the turbine speed and output speed sensors to determine the current commanded for steady-state gear ratio. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. No shift in progress.
3. Hydraulic default condition not present.
4. Output speed is above 200 rpm.
5. Engine initialization or shutdown is not in process.

CONDITIONS FOR SETTING THE DTC:
DTC P077F sets during steady-state condition when the calculated reverse (R2) gear ratio differs from the known reverse (R2) gear ratio for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P077F is active, the following conditions will occur:
1. Locks in Neutral (N).
2. While diagnostic response is active, the TCM ignores shift selector inputs.
3. The CHECK TRANS light illuminates.
4. DTC is stored in the TCM history.
5. TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
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:
NOTE: A second “deep reverse” gear (R2) was released January 2010 for 4700RDS, 4700EVS, 4800EVS and 4700/4800 International transmission models. The 47000FS version was released June 2010. The R2 gear ratio is 17.12. The standard reverse (R1) gear ratio is 4.80. The 4th Generation selectors display a lowercase “r” when in R2 range and an uppercase R when in R1 range. Refer to the OEM Technician’s Library for R2 vehicle integration information.

DTC P077F may be caused by:
1. Output speed sensor signal circuit issues.
2. Turbine speed sensor signal circuit issues.
3. Low clutch pressures, main pressure, or control main pressure.
4. Control module issues like stuck/sticky valves, mechanically defective solenoids, broken springs, damaged valve bores, plugged suction filter, damaged gaskets, excessive leaks to exhaust, etc.
5. Transmission issues such as worn and/or damaged seals or seal rings, dislocated snap rings, worn clutch packs, rotating drum damage (affecting turbine speed pickup), debris, excessive hydraulic circuit leaks to exhaust or other hydraulic circuits.
6. Clutch system issues causing a clutch not to release.
7. Issue with TCM.

DIAGNOSTIC RESPONSE:
DNS, RPR

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses input from the turbine speed and output speed sensors to determine the current commanded for steady-state gear ratio. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

This DTC test determines if the on-coming clutch controlled by Pressure Control Solenoid 3 (PCS3) engages during a forward range shift. PCS3 controls the C5 clutch for Neutral, 1st, and Reverse. PCS3 does not control clutches for Reverse 2. PCS3 controls C3 clutch in 3rd and 5th range.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. Hydraulic default condition not present.
3. Output speed is above 125 rpm.
4. Turbine speed above 60 rpm.
5. Engine initialization or shutdown is not in process.

CONDITIONS FOR SETTING THE DTC:
DTC P0796 sets when the TCM detects the on-coming clutch did not maintain engagement after 2 seconds during the range shifts that require PCS3 to control either C3 or C5 clutch.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0796 is active, the following conditions will occur:
1. If DTC goes active while making a forward range shift (e.g., 1-2), the transmission returns to the previous range. If DTC goes active during a shift to reverse or neutral, the transmission shifts to neutral. Once shifting is complete, the attained range is locked in range.
2. While diagnostic response is active, the TCM ignores shift selector inputs.
3. The CHECK TRANS light illuminates.
4. DTC is stored in the TCM history.
5. TCM inhibits TCC engagement.
6. TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
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:
NOTE: This DTC requires Clutch Test using the diagnostic tool to detect clutch slip during a partial stall and also to pressurize clutches for measurement without needing to drive the vehicle. Note that main pressure and clutch pressures are reduced when the Main Mod Solenoid is energized. Low commanded Main Mod solenoid pressures shown in Data Monitor correlate to reduced main pressure and clutch pressures. Main pressure is reduced by Main Mod in N (Neutral), 1 (First Range), and 2 (Second Range) when engine speed is below 1500 rpm. Higher Main Mod commanded pressures correlate to no reduction in main pressure and clutch pressures. Refer to First Steps and Troubleshooting and the OEM Technician’s Library for more information about the action requests for Clutch Test, Full Main Pressure Test, and also the procedure for Stall Testing.

DTC P0796 may be caused by:
1. Output speed sensor signal circuit issues.
2. Turbine speed sensor signal circuit issues.
3. Low clutch pressures, main pressure, or control main pressure.
4. Control module issues like stuck/sticky valves, mechanically defective solenoids, broken springs, damaged valve bores, plugged suction filter, damaged gaskets, excessive leaks to exhaust, etc.
5. Transmission issues such as damaged output speed sensor wheel slot, worn and/or damaged seals or seal rings, dislocated snap rings, worn clutch packs, rotating drum damage (affecting turbine speed pickup), debris, excessive hydraulic circuit leaks to exhaust or other hydraulic circuits.

NOTE: Damage to the output speed sensor wheel slot is an indication the driveline does not meet ATI specifications. Correct all driveline issues before putting transmission back in service.

6. Issue with TCM.
7. A high resistance circuit in Shift Solenoid 1 (SS1) low side solenoid wire (W151) may cause this code. There may be a P0973 in history with this code. SS1 strokes the C2 latch valve when energized. A high resistance connection may not fully energize the SS1 in order to stroke the C2 latch. Check for expanded terminals, broken/loose connectors, loose pin crimps, or damaged W151 in chassis harness. Check condition of wire harness in control valve module and the SS1 resistance if needed.
8. PCS2 controls either the C2 or C3 clutch. However, this code may also occur when any other clutch did not maintain engagement while PCS2 is commanded.

DIAGNOSTIC RESPONSE:
DNS, RPR

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) uses input from the turbine speed and output speed sensors to determine the current commanded for steady-state gear ratio. The TCM then compares the known gear ratio to the calculated gear ratio for the current range.

This DTC test determines if the off-going clutch controlled by Pressure Control Solenoid 3 (PCS3) remains engaged during a forward range shift. PCS3 controls the CS clutch for Neutral, 1st, and Reverse. PCS3 does not control clutches for Reverse 2. PCS3 controls C3 clutch in 3rd and 5th range.

CONDITIONS FOR RUNNING THE DTC:
1. Hydraulic system is pressurized.
2. Hydraulic default condition not present.
3. Output speed is 200 rpm or higher.
4. Turbine speed is 200 rpm or higher.
5. Engine initialization or shutdown is not in process.

CONDITIONS FOR SETTING THE DTC:
DTC P0797 sets when the TCM detects the off-going clutch did not fully release after 2 seconds during the range shifts that require PCS3 to control either C3 or CS clutch.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0797 is active, the following conditions will occur:
1. If DTC goes active while making a forward range shift (e.g., 1-2), the transmission returns to the previous range. If DTC goes active during a shift to reverse or neutral, the transmission shifts to neutral. Once shifting is complete, the attained range is locked in range.
2. While diagnostic response is active, the TCM ignores shift selector inputs.
3. The CHECK TRANS light illuminates.
4. DTC is stored in the TCM history.
5. TCM inhibits TCC engagement.
6. TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
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:
NOTE: This DTC requires Clutch Test using the diagnostic tool to detect clutch slip during a partial stall and also to pressurize clutches for measurement without needing to drive the vehicle. Note that main pressure and clutch pressures are reduced when the Main Mod Solenoid is energized. Low commanded Main Mod solenoid pressures shown in Data Monitor correlate to reduced main pressure and clutch pressures. Main pressure is reduced by Main Mod in N (Neutral), 1 (First Range), and 2 (Second Range) when engine speed is below 1500 rpm. Higher Main Mod commanded pressures correlate to no reduction in main pressure and clutch pressures. Refer to First Steps and Troubleshooting and the OEM Technician’s Library for more information about the action requests for Clutch Test, Full Main Pressure Test, and also the procedure for Stall Testing.

DTC P0797 may be caused by:
1. Output speed sensor signal circuit issues.
2. Turbine speed sensor signal circuit issues.
3. Low clutch pressures, main pressure, or control main pressure.
4. Control module issues like stuck/sticky valves, mechanically defective solenoids, broken springs, damaged valve bores, plugged suction filter, damaged gaskets, excessive leaks to exhaust, etc.
5. Transmission issues such as damaged output speed sensor wheel slot, worn and/or damaged seals or seal rings, dislocated snap rings, worn clutch packs, rotating drum damage (affecting turbine speed pickup), debris, excessive hydraulic circuit leaks to exhaust or other hydraulic circuits.

NOTE: Damage to the output speed sensor wheel slot is an indication the driveline does not meet ATI specifications. Correct all driveline issues before putting transmission back in service.

6. Issue with TCM.
7. A high resistance circuit in Shift Solenoid 1 (SS1) low side solenoid wire (W151) may cause this code. There may be a P0973 in history with this code. SS1 strokes the C2 latch valve when energized. A high resistance connection may not fully energize the SS1 in order to stroke the C2 latch. Check for expanded terminals, broken/loose connectors, loose pin crimps, or damaged W151 in chassis harness. Check condition of wire harness in control valve module and the SS1 resistance if needed.
8. PCS3 controls either the C3 or CS clutch. However, this code may also occur for any other off going clutch issue while PCS3 is commanded.

DIAGNOSTIC RESPONSE:
DNS, Lock in current range

CIRCUIT DESCRIPTION:
C1 and C2 latch valve logic states (stroked/destroked) control clutch pressure routing based on latch valve location. The four possible combinations for C1/C2 latch location are the following:

C1 Latch Valve C2 Latch Valve
Destroked Destroked
Stroked Destroked
Destroked Stroked
Stroked Stroked

The TCM knows which solenoids should be commanded to attain a specific range and will use the PS1 switch state (open= PRESSURIZED and closed = EXHAUSTED) to confirm if the actual transmission range attained matches the TCMs known commanded range.

PS1 is used by the TCM to sense the PCS2 regulator (trim) valve position (stroked or destroked) and the C3 clutch state (pressurized or exhausted) when the C5 clutch is filled. C5 is filled in Reverse, Neutral, and 1st range. Also, PS1 is used to sense the C1 and C2 latch valve positions (stroked/destroked) when the C5 clutch is exhausted. C5 is exhausted in Low (7-speed) and 2nd through 6th ranges.

During normal operation the TCM expects PS1 to indicate PRESSURIZED (open) in Reverse and 2nd through 5th ranges. The TCM expects PS1 to indicate EXHAUSTED (closed) in Neutral (N), Low (for 7 speeds), 1st and 6th range. DTC P0842 becomes active if the PS1 switch is detected as EXHAUSTED (closed) when it should be detected PRESSURIZED (open).

With key ON and engine OFF, normal PS1 state is EXHAUSTED because it is a Normally Closed (NC) switch.

When PS1 is closed, W177 (PS1 input) is switched to W158 (analog return) and the diagnostic tool shows the switch EXHAUSTED. When PS1 is open, W177 will pull up the voltage internally on terminal 77 and the diagnostic tool shows the switch PRESSURIZED. PS1 opens at approximately 175-200 kPa (25-30 psi).

CONDITIONS FOR RUNNING THE DTC:
1. TCM initialization is complete.
2. Hydraulic system pressurized.
3. Transmission fluid temperature greater than -10°C (14°F).
4. When C5 clutch command is not in transition.
5. When C5 clutch is filled and PCS2 regulator (trim) valve is commanded stroked, or C5 is commanded to exhaust and both latch valves are commanded stroked.

CONDITIONS FOR SETTING THE DTC:
DTC P0842 sets when PS1 indicates EXHAUSTED (closed) when the TCM expects PS1 switch state to be PRESSURIZED (open). DTC may set while commanding Reverse and 2nd through 5th ranges.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0842 is active:
1. If failure occurs while in a forward range, then shift to another forward range. If failure occurs while in Reverse (R), the transmission remains in Reverse (R) or shifts to Neutral (N). Once range is attained, the transmission will be locked in range. There is no response to shift selector requests.
2. The TCM inhibits TCC engagement.
3. DTC is stored in the TCM history.
4. The CHECK TRANS light illuminates.
5. 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 failure.

DIAGNOSTIC AIDS:
DTC P0842 can be caused by:
1. Unapproved fluid, contaminated fluid, e.g., glycol, water, etc.
2. W177 shorted to ground in chassis harness.
3. W177 (terminal 3 of 20-way) shorted to ground in internal transmission harness.
4. PS 1 issues such as:
– PS1 switch stuck mechanically closed.
– PS1 intermittently will not open.
– PS1 shorted to ground.
5. PCS1, PCS2, PCS3 solenoid or trim valve issues such as:
– Broken trim spring.
– Debris in trim valve bores causing sticking valves.
– Solenoids mechanically defective.
6. C1/C2 latch valve issues such as:
– Debris in valve body sticking C1 or C2 latch valve.
7. Defective solenoids SS1 or SS2 (7-speed models).
8. Broken or defective connector assemblies allowing pushed back pins to short together.
9. Unlocked connectors, missing seal plugs allowing moisture in connectors.
10. Incorrect service parts installed, e.g., non-prognostics channel plate gasket used on prognostics control module, etc.

NOTE: Channel plates, solenoid and main valve bodies, separator plates, and channel plates are incompatible between former non-prognostics control valve modules and current prognostics control valve modules. Do not intermix parts because DTCs will result.

11. Low or loss of C5 pressure.
12. Low main pressure.
13. Defective TCM.

Review applicable information in Control System and Transmission Specifications to find additional circuit specifications, system and connector diagrams, and troubleshooting tips.