Allison

DIAGNOSTIC RESPONSE:
DNS, SOL OFF (hydraulic default)

CIRCUIT DESCRIPTION:
The high side drivers are connected to the high side circuits of the solenoids and commanded on during normal operation. The high side drivers serve as a master switch to supply battery voltage to the low side drivers. High side drivers are tuned on during Transmission Control Module (TCM) initialization, and remain on during normal operation. High side drivers are turned off during cranking and certain diagnostic responses. High Side Driver 3 (HSD3) supplies battery voltage to the Torque Converter Clutch (TCC) solenoid, Pressure Clutch Solenoid 5 (PCS5) and Shift Solenoid 2 (SS2) via W131. The TCM regulates control current to the solenoids by switching the appropriate low side driver on and off. This test detects if the voltage measured at the HSD3 detection circuit indicates high during initialization when the circuit is off.

CONDITIONS FOR RUNNING THE DTC:
During TCM initialization while high side driver is commanded off.

CONDITIONS FOR SETTING THE DTC:
This DTC sets during TCM initialization, if HSD3 voltage detected to be greater than 6V while HSD3 circuit is OFF.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2686 is active:
1. Transmission fails to Neutral (N).
2. DTC is stored in the TCM history.
3. The CHECK TRANS light illuminates.
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 failure.

DIAGNOSTIC AIDS:
DTC P2686 can be caused by:
1. HSD3 circuit issues such as:
– W131 shorted to another wire in chassis harness.
– W131 (terminal 11 of 20-way) shorted to another wire in the internal transmission harness.
2. TCC issues such as:
– W137 shorted to another wire in chassis harness.
– W137 shorted (terminal 12 of 20-way) to another wire in the internal transmission harness.
3. PCS5 (7-speed Differential Lock, retarder) issues such as:
– W115 shorted to another wire in chassis harness.
4. SS2 issues such as:
– W119 shorted to another wire in chassis harness.
– W119 shorted (terminal 17 of 20-way) to another wire in the internal transmission harness.
5. Air solenoid (SS2) issues such as:
– W119 shorted to another wire in chassis harness.
6. Defective solenoids TCC, PCS5 (retarder solenoid), SS2, air solenoid (SS2), or differential lock solenoid (PCS5).
7. Broken or defective connector assemblies allowing pushed back pins to short together.
8. Unlocked connectors, missing seal plugs allowing moisture in connectors.
9. Defective TCM.

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

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 4 (PCS4) engages during a forward range shift. PCS4 controls the C4 clutch for 2nd and 6th range in all 3000 and 4000 transmissions.

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 P2714 sets when the TCM detects the on-coming clutch did not maintain engagement after 2 seconds during the range shifts that require PCS4 to control C4 clutch.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2714 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 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 P2714 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. PCS4 controls the C4 clutch. However, this code may also occur when any other clutch did not maintain engagement while C4 is commanded.

8. PCS4 controls the C4 clutch. However, this code may also occur for any other off-going clutch issue while C4 is commanded.

DIAGNOSTIC RESPONSE:
DNS, SOL OFF (hydraulic default)

CIRCUIT DESCRIPTION:
Pressure Control Solenoid 4 (PCS4) is a normally closed solenoid used to apply the C4 clutch in 2nd and 6th ranges. The Transmission Control Module (TCM) commands the solenoid ON to produce hydraulic pressure in the clutch apply circuit. When PCS4 is commanded OFF, the clutch pressure is released. The TCM sends control current to PCS4 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 PCS4 by switching PCS4 low side driver ON and OFF. Wire 155 completes the circuit between PCS4 and its low side driver. DTC P2718 indicates that the TCM has detected an open condition in the PCS4 electrical circuit. The open condition may exist in the high side (wire 111) or low side (wire 155).

CONDITIONS FOR RUNNING THE DTC:
TCM initialized normally and engine speed above 200 rpm.

CONDITIONS FOR SETTING THE DTC:
This DTC sets when the TCM detects PCS4 low side driver has been detected in a failed open state.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2718 is active:
1. If failure occurs while in a forward range, then shifts to another forward range. If failure occurs while in Neutral (N), the transmission remains in Neutral (N). If failure occurs while in Reverse (R), the transmission remains in Reverse (R) or shifts to Neutral (N). Once range is attained, transmission will be locked in range. There is no response to shift selector requests.
2. DTC is stored in the TCM history.
3. The CHECK TRANS light illuminates.
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 failure.

DIAGNOSTIC AIDS:
DTC P2718 can be caused by:
1. PCS4 issues such as:
– W155 high resistance or an open circuit in chassis harness.
– W155 (terminal 2 of 20-way) high resistance or an open circuit in internal transmission harness.
– PCS4 defective.
2. Unlocked connectors, expanded terminals, poor pin crimps or unlocked pins causing high resistance or open circuit.
3. Defective TCM.

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

DIAGNOSTIC RESPONSE:
DNS, SOL OFF (hydraulic default)

CIRCUIT DESCRIPTION:
Pressure Control Solenoid 4 (PCS4) is a normally closed solenoid used to apply the C4 clutch in 2nd and 6th ranges. The Transmission Control Module (TCM) commands the solenoid ON to produce hydraulic pressure in the clutch apply circuit. When PCS4 is commanded OFF, the clutch pressure is released. The TCM sends control current to PCS4 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 PCS4 by switching PCS4 low side driver ON and OFF. Wire 155 completes the circuit between PCS4 and its low side driver. DTC P2720 indicates that the TCM has detected a failed low condition in the PCS4 electrical circuit. The condition may exist in the high side (wire 111) or low side (wire 155).

CONDITIONS FOR RUNNING THE DTC:
TCM initialized normally and engine speed above 200 rpm.

CONDITIONS FOR SETTING THE DTC:
This DTC sets when the TCM detect PCS4 low side driver has been detected in a failed low state.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2720 is active:
1. If failure occurs while in a forward range, then shift to another forward range. If failure occurs while in Neutral (N), the transmission remains in Neutral (N). 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. DTC is stored in the TCM history.
3. The TCM inhibits Torque Converter Clutch (TCC) engagement.
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 P2720 can be caused by:
1. PCS4 issues such as:
– W155 short in chassis harness.
– W155 (terminal 2 of 20-way) short in internal transmission harness.
– PCS4 defective.
2. Broken or defective connector assemblies allowing pushed back pins to short together.
3. Unlocked connectors, missing seal plugs allowing moisture in connectors.
4. Defective TCM.

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

DIAGNOSTIC RESPONSE:
DNS, SOL OFF (hydraulic default)

CIRCUIT DESCRIPTION:
Pressure Control Solenoid 4 (PCS4) is a normally closed solenoid used to apply the C4 clutch in 2nd and 6th ranges. The Transmission Control Module (TCM) commands the solenoid ON to produce hydraulic pressure in the clutch apply circuit. When PCS4 is commanded OFF, the clutch pressure is released. The TCM sends control current to PCS4 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 PCS4 by switching PCS4 low side driver ON and OFF. Wire 155 completes the circuit between PCS4 and its low side driver. DTC P2721 indicates that the TCM has detected a failed high condition in the PCS4 electrical circuit.

CONDITIONS FOR RUNNING THE DTC:
TCM initialized normally and engine speed above 200 rpm.

CONDITIONS FOR SETTING THE DTC:
This DTC sets when the TCM detects PCS4 low side driver has been detected in a failed high state.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2721 is active:
1. If failure occurs while in forward range, then shift to another forward range. If failure occurs while in Neutral (N), the transmission remains in Neutral (N). 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. DTC is stored in the TCM history.
3. The TCM inhibits Torque Converter Clutch (TCC) engagement.
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 P2721 can be caused by:
1. PCS4 issues such as:
– W155 short in chassis harness.
– W155 (terminal 2 of 20-way) short in internal transmission harness.
– PCS4 defective.
2. Broken or defective connector assemblies allowing pushed back pins to short together.
3. Unlocked connectors, missing seal plugs allowing moisture in connectors.
4. Defective TCM.

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

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 1 (PCS1) engages during a forward range shift. PCS1 controls the C1 clutch for 1st through 4th gears in all 3000 and 4000 transmissions, and the Low range in 4700/4800 transmissions. PCS1 does not control clutches for Low range in the 3700 transmission.

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 P2723 sets when the TCM detects the on-coming clutch did not maintain engagement after 2 seconds during the range shifts that require PCS1 to control C1 clutch.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2723 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 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 P2723 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. PCS1 controls the C1 clutch. However, this code may also occur when any on-coming clutch did not maintain engagement while C1 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 1 (PCS1) remains engaged during a forward range shift. PCS1 controls the C1 clutch for 1st through 4th gears in all 3000 and 4000 transmissions, and the Low range in 4700/4800 transmissions. PCS1 does not control clutches for Low range in the 3700 transmission.

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 P2724 sets when the TCM detects the off-going clutch did not fully release after 2 seconds during the range shifts that require PCS1 to control C1 clutch.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2724 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
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
NOTE: This DTC requires Clutch Test using 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 refer to 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 P2724 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. PCS1 controls the C1 clutch. However, this code may also occur for any off-going clutch issue while C1 is commanded.

DIAGNOSTIC RESPONSE:
DNS, SOL OFF (hydraulic default)

CIRCUIT DESCRIPTION:
Pressure Control Solenoid 1 (PCS1) is a normally open solenoid used to apply the C1 clutch in 1st and 4th range. The Transmission Control Module (TCM) commands the solenoid OFF to produce hydraulic pressure in the clutch apply circuit. When PCS1 is commanded ON, the C1 clutch is released. The TCM sends control current to PCS1 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously ON unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS1 by switching PCS1 low side driver ON and OFF. Wire 136 completes the circuit between PCS1 and its low side driver. DTC P2727 indicates that the TCM has detected an open condition in the PCS1 electrical circuit. The open condition may exist in the high side (wire 171) or low side (wire 136).

CONDITIONS FOR RUNNING THE DTC:
TCM initialized normally and engine speed above 200 rpm.

CONDITIONS FOR SETTING THE DTC:
This DTC sets when the TCM detects PCS1 low side driver has been detected in a failed open state.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P2727 is active:
1. If failure occurs while in a forward range, then the transmission shifts to another forward range. If failure occurs while in Neutral (N), transmission remains in Neutral (N). If failure occurs while in Reverse (R), transmission remains in Reverse (R) or shifts to Neutral (N). Once range is attained, transmission will be locked in range. There is no response to shift selector requests.
2. DTC is stored in the TCM history.
3. The CHECK TRANS light illuminates.
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 failure.

DIAGNOSTIC AIDS:
DTC P2727 can be caused by:
1. PCS1 issues such as:
– W136 high resistance or an open circuit in chassis harness.
– W136 (terminal 4 of 20-way) high resistance or an open circuit in internal transmission harness.
– PCS1 defective.
2. Unlocked connectors, expanded terminals, poor pin crimps or unlocked pins causing high resistance or open circuit.
3. Defective TCM.

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