Automatic Transaxle - 4t65- E - DTC p0752 to DTC p1822 Buick LaCrosse I

Scheme 75

Circuit Description

The 1-2 shift solenoid (1-2 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the TCM. When the TCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the TCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The TCM identifies a 1-2 SS valve condition by monitoring the commanded gear versus gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects a 2nd gear ratio when 1st gear is commanded and a 3rd gear ratio when 4th gear is commanded, then DTC P0751 sets. DTC P0751 is a type B DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P0751 1-2 Shift Solenoid (SS) Valve Performance - No First or Fourth Gear

Conditions for Running the DTC

1. No TP sensor DTC P0121, P0122 or P0123.
2. No ISS DTC P0716 or P0717.
3. No OSS DTC P0722 or P0723.
4. No TCC system stuck ON DTC P0742.
5. No 1-2 SS valve electrical DTC P0973 or P0974.
6. No 2-3 SS valve electrical DTC P0976 or P0977.
7. The engine speed is greater than 500 RPM for 5 seconds.
8. The calc. throttle position is 8 percent or more.
9. The transmission fluid temperature is between 20°C (68°F) and 130°C (266°F).
10. The engine torque is greater than 50 N.m (37lb ft).
11. The transmission ISS is 150 RPM or more.
12. The transmission OSS is 53 RPM or more.
13. The time since the last gear change is 1.5 seconds.

Conditions for Setting the DTC

The following conditions both occur twice in one trip

Condition 1

The TCM commands 1st gear and the gear ratio indicates 2nd gear, 1.48:1 to 1.65:1, for 2 seconds.

Condition 2

The TCM commands 4th gear and the gear ratio indicates 3rd gear, 0.95:1 to 1.05:1, for 3 seconds.

Action Taken When the DTC Sets

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM commands maximum line pressure.
3. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
4. The TCM freezes transmission adaptive functions.
5. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
6. The TCM stores DTC P0751 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Diagnostic Aids

If DTC P0751 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

Test Description

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the TCM commanded all the shifts, but all the shifts did not occur.

DTC P0751 (3.6L)

Scheme 76

The 1-2 shift solenoid (1-2 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the PCM. When the PCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the PCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The PCM identifies a 1-2 SS valve condition by monitoring the commanded gear versus gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the PCM detects a 2nd gear ratio when 1st gear is commanded and a 3rd gear ratio when 4th gear is commanded, then DTC P0751 sets. DTC P0751 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P0751 1-2 Shift Solenoid (SS) Valve Performance - No First or Fourth Gear

1. No VSS DTC P0502 or P0503.
2. No ISS DTC P0716 or P0717.
3. No TCC system stuck ON DTC P0742.
4. No 1-2 SS valve electrical DTC P0753.
5. No 2-3 SS valve electrical DTC P0758.
6. No TCC PWM solenoid valve DTC P2761.
7. The engine is running for greater than 5 seconds and not in fuel cut off.
8. The transmission fluid temperature is 20-130°C (68-266°F).
9. The transmission ISS is 150 RPM or more.
10. The transmission OSS is 300 RPM or more.
11. The time since the last gear range change is greater than 1 second.

The following conditions both occur twice in one trip

The PCM commands 1st gear with the TP angle 5 percent or more, the engine torque is between 27 N.m (20 lb ft) and 271 N.m (200 lb ft) and the gear ratio indicates 2nd gear, 1.52:1 to 1.60:1, for 1 second.

The PCM commands 4th gear with the TP angle 10 percent or more, the engine torque is between 41 N.m (30 lb ft) and 271 N.m (200 lb ft) and the gear ratio indicates 3rd gear, 0.95:1 to 1.05:1, for 1 second.

1. The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes transmission adaptive functions.
4. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
5. The PCM stores DTC P0751 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

If DTC P0751 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the PCM commanded all the shifts, but all the shifts did not occur.

DTC P0751 (3.8L)

The 1-2 shift solenoid (1-2 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the TCM. When the TCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the TCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The TCM identifies a 1-2 SS valve condition by monitoring the commanded gear versus gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects a 1st gear ratio when 2nd gear is commanded and a 4th gear ratio when 3rd gear is commanded, then DTC P0752 sets. DTC P0752 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P0752 1-2 Shift Solenoid (SS) Valve Performance - No Second or Third Gear

1. No TP sensor DTC P0121, P0122 or P0123.
2. No ISS DTC P0716 or P0717.
3. No OSS DTC P0722 or P0723.
4. No TCC system stuck ON DTC P0742.
5. No 1-2 SS valve electrical DTC P0973 or P0974.
6. No 2-3 SS valve electrical DTC P0976 or P0977.
7. The engine speed is greater than 500 RPM for 5 seconds.
8. The calc. throttle position is 8 percent or more.
9. The transmission fluid temperature is between 20°C (68°F) and 130°C (266°F).
10. The engine torque is greater than 50 N.m (37 lb ft).
11. The transmission ISS is 150 RPM or more.
12. The transmission OSS is 53 RPM or more.
13. The time since the last gear range change is 1.5 seconds.

The following conditions both occur twice in one trip

The TCM commands 2nd gear and the gear ratio indicates 1st gear, 2.78:1 to 3.09:1, for 2 seconds.

The TCM commands 3rd gear and the gear ratio indicates 4th gear, 0.67:1 to 0.74:1, for 2 seconds.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM commands maximum line pressure.
3. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
4. The TCM inhibits 3-2 downshifts when the vehicle speed is greater than 52 km/h (32 mph).
5. The TCM freezes transmission adaptive functions.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
7. The TCM stores DTC P0752 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

If DTC P0752 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the TCM commanded all the shifts, but all the shifts did not occur.

DTC P0752 (3.6L)

The 1-2 shift solenoid (1-2 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the PCM. When the PCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the PCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The PCM identifies a 1-2 SS valve condition by monitoring the commanded gear versus gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the PCM detects a 1st gear ratio when 2nd gear is commanded and a 4th gear ratio when 3rd gear is commanded, then DTC P0752 sets. DTC P0752 is a type B DTC.

1. No VSS DTC P0502 or P0503.
2. No ISS DTC P0716 or P0717.
3. No TCC system stuck ON DTC P0742.
4. No 1-2 SS valve electrical DTC P0753.
5. No 2-3 SS valve electrical DTC P0758.
6. No TCC PWM solenoid valve DTC P2761.
7. The engine speed is greater than 500 RPM for 5 seconds and not in fuel cut off.
8. The TP indicated angle is 10 percent or more.
9. The transmission fluid temperature is 20-130°C (68-266°F).
10. The engine torque is 27-271 N.m (20-200 lb ft).
11. The transmission ISS is 150 RPM or more.
12. The transmission OSS is 300 RPM or more.
13. The time since the last range change is 1 second or more.

The following conditions both occur twice in one trip

The PCM commands 2nd gear and the gear ratio indicates 1st gear, 2.87:1 to 2.97:1, for 1 second.

The PCM commands 3rd gear and the gear ratio indicates 4th gear, 0.65:1 to 0.75:1, for 1 second.

1. The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes transmission adaptive functions.
4. The PCM inhibits 3-2 downshifts when the vehicle speed is greater than 49 km/h (30 mph).
5. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
6. The PCM stores DTC P0752 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

If DTC P0752 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the PCM commanded all the shifts, but all the shifts did not occur.

DTC P0752 (3.8L)

Scheme 77

The 1-2 shift solenoid (1-2 SS) valve controls transmission fluid pressure acting on the 1-2 shift valves to position the valves for the appropriate gear. The 1-2 SS valve is a normally-open exhaust valve located on the control valve body. A fused circuit supplies ignition voltage to the 1-2 SS valve. The powertrain control module (PCM) commands the solenoid ON or OFF by switching the ground path. When the 1-2 SS valve is commanded ON, the PCM senses low voltage. When the 1-2 SS valve is commanded OFF, the PCM senses high voltage. Refer to Shift Solenoid Valve State and Gear Ratio .

If the PCM detects a continuous open, short to ground or short to voltage in the 1-2 SS valve circuit, then DTC P0753 sets. DTC P0753 is a type B DTC.

The engine speed is greater than 500 RPM for 5 seconds and not in fuel cut off.

DTC P0753 sets when one of the following conditions occurs for 5 seconds

The PCM commands the solenoid ON and voltage feedback remains high, B+.

The PCM commands the solenoid OFF and the voltage feedback remains low, 0 volts.

1. The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes transmission adaptive function.
4. The PCM inhibits 3-2 downshifts when the vehicle speed is greater than 49 km/h (30 mph).
5. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
6. The PCM stores DTC P0753 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections .

The number below refers to the step number on the diagnostic table.

1. 2: A short to ground in the ignition voltage circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but, would set the other DTCs.

DTC P0753 (3.8L)

Scheme 78

The 2-3 shift solenoid (2-3 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the TCM. When the TCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the TCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The TCM identifies a 2-3 SS valve performance condition by monitoring the commanded gear versus the gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects a 4th gear ratio when 1st gear is commanded and a 3rd gear ratio when 2nd gear is commanded, then DTC P0756 sets. DTC P0756 is a type A DTC.

This diagnostic procedure supports the following DTC

DTC P0756 2-3 Shift Solenoid (SS) Valve Performance - No First or Second Gear

1. No TP sensor DTC P0121, P0122 or P0123.
2. No ISS DTC P0716 or P0717.
3. No OSS DTC P0722 or P0723.
4. No TCC stuck ON DTC P0742.
5. No 1-2 SS valve electrical DTC P0973 or P0974.
6. No 2-3 SS valve electrical DTC P0976 or P0977.
7. The engine speed is greater than 500 RPM for 5 seconds.
8. The transmission fluid temperature is between 20°C (68°F) and 130°C (266°F).
9. The calc. throttle position is 8 percent or more.
10. The engine torque is 50 N.m (37 lb ft) or more.
11. The transmission ISS is 150 RPM or more.
12. The transmission OSS is 53 RPM or more.
13. The time since the last gear change is 1.5 seconds.

The following conditions both occur twice in one trip

The TCM commands 1st gear with the TCC slip speed greater than -20 RPM and the gear ratio indicates 4th gear, 0.65:1 to 1.87:1, for 3 seconds.

The TCM commands 2nd gear and the gear ratio indicates 3rd gear, 0.95:1 to 1.05:1, for 3 seconds.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
2. The TCM inhibits 1st gear.
3. The TCM commands maximum line pressure.
4. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
5. The TCM freezes transmission adaptive functions.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
7. The TCM stores DTC P0756 in TCM history.

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

If DTC P0756 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the TCM commanded all the shifts, but all the shifts did not occur.

DTC P0756 (3.6L)

Scheme 79

The 2-3 shift solenoid (2-3 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the PCM. When the PCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the PCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The PCM identifies a 2-3 SS valve performance condition by monitoring the commanded gear versus the gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the PCM detects a 4th gear ratio when 1st gear is commanded and a 3rd gear ratio when 2nd gear is commanded, then DTC P0756 sets. DTC P0756 is a type A DTC.

This diagnostic procedure supports the following DTC

DTC P0756 2-3 Shift Solenoid (SS) Valve Performance - No First or Second Gear

1. No VSS DTC P0502 or P0503.
2. No ISS DTC P0716 or P0717.
3. No TCC system stuck ON DTC P0742.
4. No 1-2 SS valve electrical DTC P0753.
5. No 2-3 SS valve electrical DTC P0758.
6. No TCC PWM solenoid valve DTC P2761.
7. The engine speed is greater than 500 RPM for 5 seconds and not in fuel cut off.
8. The transmission fluid temperature is 20-130°C (68-266°F).
9. The TP indicated angle is 10 percent or more.
10. The engine torque is 81-271 N.m (60-200 lb ft).
11. The transmission ISS is 150 RPM or more.
12. The time since the last range change is 1 second or more.

The following conditions both occur twice in one trip

The PCM commands 1st gear with the transmission OSS 100 RPM or more and the gear ratio indicates 4th gear, 0.65:1 to 0.75:1, for 1 second.

The PCM commands 2nd gear with the transmission OSS 300 RPM or more and the gear ratio indicates 3rd gear, 0.95:1 to 1.05:1, for 1 second.

1. The PCM illuminates the malfunction indicator lamp (MIL).
2. The PCM commands 3rd gear.
3. The PCM commands maximum line pressure.
4. The PCM freezes transmission adaptive functions.
5. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
6. The PCM stores DTC P0756 in PCM history.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

If DTC P0756 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the PCM commanded all the shifts, but all the shifts did not occur.

DTC P0756 (3.8L)

The 2-3 shift solenoid (2-3 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the TCM. When the TCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the TCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The TCM identifies a 2-3 SS valve performance condition by monitoring the commanded gear versus the gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects a 2nd gear ratio when 3rd gear is commanded and a 1st gear ratio when 4th gear is commanded, then DTC P0757 sets. DTC P0757 is a type A DTC.

This diagnostic procedure supports the following DTC

DTC P0757 2-3 Shift Solenoid (SS) Valve Performance - No Third or Fourth Gear

1. No TP sensor DTC P0121, P0122 or P0123.
2. No ISS DTC P0716 or P0717.
3. No OSS DTC P0722 or P0723.
4. No TCC system stuck ON DTC P0742.
5. No 1-2 SS valve electrical DTC P0973 or P0974.
6. No 2-3 SS valve electrical DTC P0976 or P0977.
7. The engine speed is greater than 500 RPM for 5 seconds.
8. The engine torque is 40 N.m (30 lb ft) or more when 3rd gear is commanded.
9. The transmission fluid temperature is between 20°C (68°F) and 130°C (266°F).
10. The calc. throttle position is 8 percent or more.
11. The transmission ISS is 150 RPM or more.
12. The transmission OSS is 53 RPM or more.
13. The time since the last gear change is 1.5 seconds.

The following conditions both occur twice during the same ignition cycle

The TCM commands 3rd gear and the gear ratio indicates 2nd gear, 1.48:1 to 1.65:1, for 2 seconds.

The TCM commands 4th gear and the gear ratio indicates 1st gear, 1.65:1 to 3.09:1, for 2 seconds.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
2. The TCM commands maximum line pressure.
3. The TCM inhibits 4th gear.
4. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
5. The TCM freezes transmission adaptive functions.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
7. The TCM stores DTC P0757 in TCM history.

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

If DTC P0757 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the TCM commanded all the shifts, but all the shifts did not occur.

DTC P0757 (3.6L)

The 2-3 shift solenoid (2-3 SS) valve is supplied with fused ignition voltage. The ground path is controlled by the PCM. When the PCM commands the solenoid OFF, a ground path is not provided and the filtered line pressure that is fed to the solenoid is exhausted. When the PCM commands the solenoid ON, a ground path is provided and the exhaust port is blocked, stopping the exhaust of line pressure.

The PCM identifies a 2-3 SS valve performance condition by monitoring the commanded gear versus the gear ratio. Refer to Shift Solenoid Valve State and Gear Ratio .

If the PCM detects a 2nd gear ratio when 3rd gear is commanded and a 1st gear ratio when 4th gear is commanded, then DTC P0757 sets. DTC P0757 is a type A DTC.

This diagnostic procedure supports the following DTC

DTC P0757 2-3 Shift Solenoid (SS) Valve Performance - No Third or Fourth Gear

1. No VSS DTC P0502 or P0503.
2. No ISS DTC P0716 or P0717.
3. No TCC system stuck ON DTC P0742.
4. No 1-2 SS valve electrical DTC P0753.
5. No 2-3 SS valve electrical DTC P0758.
6. No TCC PWM solenoid valve DTC P2761.
7. The engine speed is greater than 500 RPM for 5 seconds and not in fuel cut off.
8. The transmission fluid temperature is 20-130°C (68-266°F).
9. The transmission ISS is 150 RPM or more.
10. The transmission OSS is 300 RPM or more.
11. The time since the last range change is 1 second or more.

The following conditions both occur once

The PCM commands 3rd gear with the TP angle 10 percent or more, the engine torque is between 27 N.m (20 lb ft) and 271 N.m (200 lb ft) and the gear ratio indicates 2nd gear, 1.52:1 to 1.62:1, for 1 second.

The PCM commands 4th gear with the TP angle 5 percent or more and the gear ratio indicates 1st gear, 1.80:1 to 2.97:1, for 1 second.

1. The PCM illuminates the malfunction indicator lamp (MIL).
2. The PCM commands 2nd gear.
3. The PCM commands maximum line pressure.
4. The PCM forces the TCC OFF.
5. The PCM inhibits TCC engagement.
6. The PCM freezes transmission adaptive functions.
7. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
8. The PCM stores DTC P0757 in PCM history.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

If DTC P0757 is cleared, then will not reset when the vehicle is driven, some of the following conditions may exist

1. Fluid contamination
2. Plugged fluid circuits
3. Restricted fluid circuits

The number below refers to the step number on the diagnostic table.

1. 3: This step confirms that the PCM commanded all the shifts, but all the shifts did not occur.

DTC P0757 (3.8L)

Scheme 80

The 2-3 shift solenoid (2-3 SS) valve controls transmission fluid pressure acting on the 1-2 and 2-3 shift valves to position the valves for the appropriate gear. The 2-3 SS valve is a normally-open exhaust valve located on the control valve body. A fused circuit supplies ignition voltage to the 2-3 SS valve. The powertrain control module (PCM) commands the solenoid ON or OFF by switching the ground path. When the 2-3 SS valve is commanded ON, the PCM senses low voltage. When the 2-3 SS valve is commanded OFF, the PCM senses high voltage. Refer to Shift Solenoid Valve State and Gear Ratio .

If the PCM detects a continuous open, short to ground or short to voltage in the 2-3 SS valve circuit, then DTC P0758 sets. DTC P0758 is a type A DTC.

This diagnostic procedure supports the following DTC

DTC P0758 2-3 Shift Solenoid (SS) Control Circuit

The engine speed is greater than 500 RPM for 5 seconds and not in fuel cut off.

DTC P0758 sets when one of the following conditions occurs for 5 seconds

The PCM commands the solenoid ON and the voltage feedback remains high, B+.

The PCM commands the solenoid OFF and the voltage feedback remains low, 0 volts.

1. The PCM illuminates the malfunction indicator lamp (MIL).
2. The PCM commands 3rd gear.
3. The PCM commands maximum line pressure.
4. The PCM forces the TCC OFF.
5. The PCM inhibits TCC engagement.
6. The PCM freezes transmission adaptive functions.
7. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
8. The PCM stores DTC P0758 in PCM history.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections .

The number below refers to the step number on the diagnostic table.

1. 2: A short to ground in the ignition voltage circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but, would set the other DTCs.

DTC P0758 (3.8L)

Scheme 81

The torque converter clutch (TCC) release switch is part of the transmission fluid pressure (TFP) manual valve position switch. The TFP manual valve position switch is mounted to the transmission valve body. The TCC release switch is normally-closed.

The switch signals the transmission control module (TCM) that the TCC is released. This is accomplished by torque converter release fluid pressure acting on the switch contact which opens the circuit. When the circuit voltage is high, the TCM recognizes that the TCC is no longer engaged.

If the TCM determines that the TCC release switch is closed indicating that the TCC is applied and the TCC slip speed indicates that the TCC is not applied, then DTC P0842 sets. DTC P0842 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P0842 Transmission Fluid Pressure (TFP) Sensor Circuit Low Voltage

1. No ISS DTC P0716 or P0717.
2. No TCC PWM solenoid valve performance DTC P0741 or P0742.
3. No TCC PWM solenoid valve electrical DTC P2763 or P2764.
4. The engine speed is greater than 500 RPM for 5 seconds.
5. The TCC is commanded OFF.
6. The transmission fluid temperature is 20-130°C (68-266°F).
7. The TCC slip speed is greater than 80 RPM.
8. The vehicle speed is 16km/h (10 mph) or more.
9. The engine torque is greater than 50 N.m (37 lb ft).

The TCC release pressure switch is closed indicating release pressure is not present for 10 seconds continuous twice during the same ignition cycle.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM forces the TCC ON at maximum capacity.
3. The TCM commands maximum line pressure.
4. The TCM inhibits 4th gear if the transmission is in Hot Mode.
5. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
6. The TCM freezes transmission adaptive functions.
7. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
8. The TCM stores DTC P0842 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

1. Do not replace the torque converter for this condition, refer to the «Torque Converter Replacement Guide»(/buick/lacrosse/i-2004-2009/remont/automatic-trans/#how-to-diagnosis-troubleshooting-the-automatic-transaxle-4t65-e-service__torque-converter-replacement-guide) for other concerns.
2. Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .

DTC P0842 (3.6L)

The TCC release switch is part of the transmission fluid pressure (TFP) manual valve position switch. The TFP manual valve position switch is mounted to the transmission valve body. The TCC release switch is normally-closed.

The switch signals the TCM that the TCC is released. This is accomplished by torque converter release fluid pressure acting on the switch contact which opens the circuit. When the circuit voltage is high, the TCM recognizes that the TCC is no longer engaged.

If the TCM determines that the TCC release switch is open indicating that the TCC is not applied and the TCC slip speed indicates that the TCC is applied, then DTC P0843 sets. DTC P0843 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P0843 Transmission Fluid Pressure (TFP) Sensor Circuit High Voltage

1. No ISS DTC P0716 or P0717.
2. No TCC PWM solenoid valve performance DTC P0741 or P0742.
3. No TCC PWM solenoid valve electrical DTC P2763 or P2764.
4. The engine speed is greater than 500 RPM for 5 seconds.
5. The TCC is commanded ON.
6. The transmission fluid temperature is 20-130°C (68-266°F).
7. The TCC slip speed is -20 to 60 RPM.
8. The engine torque is greater than 50 N.m (37 lb ft).

The TCC release pressure switch is open indicating release pressure is present for 6 seconds continuous twice during the same ignition cycle.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM forces the TCC OFF.
3. The TCM inhibits TCC engagement.
4. The TCM inhibits 4th gear if the transmission is in Hot Mode.
5. The TCM freezes transmission adaptive functions.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
7. The TCM stores DTC P0843 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

1. Do not replace the torque converter for this condition, refer to the «Torque Converter Replacement Guide»(/buick/lacrosse/i-2004-2009/remont/automatic-trans/#how-to-diagnosis-troubleshooting-the-automatic-transaxle-4t65-e-service__torque-converter-replacement-guide) for other concerns.
2. Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .

The number below refers to the step number on the diagnostic table.

1. 3: This step tests the TCMs ability to recognize a grounded circuit.

DTC P0843 (3.6L)

Scheme 82

The engine control module (ECM) provides 12 volts to the Park/Neutral switch of the manual shift shaft position switch. The manual shift shaft position switch is a sliding contact assembly that attaches to the manual shift shaft inside the transmission. The switch consists of five separate circuits, four of which indicate gear selector position to the transmission control module (TCM) and one that indicates Park/Neutral position to the ECM. When the transmission is in Park or Neutral, the switch closes and pulls the ECM voltage low, 0 volts. When the transmission is not in Park or Neutral, the ECM voltage is high, 12 volts. The ECM uses the switch in order to enable starter operation.

If the Park/Neutral switch and the transmission manual shift shaft position switch do not agree for a specified length of time, DTC P0850 sets. DTC P0850 is a type C DTC.

This diagnostic procedure supports the following DTC

DTC P0850 Park/Neutral Position (PNP) Switch Circuit

The ignition is ON.

DTC P0850 sets when either of the following conditions are true

The Park/Neutral switch circuit is low, 0 volts, for 100 seconds while the TCM is reporting the gear selector is in Reverse or any forward range.

The Park/Neutral switch circuit is high, 12 volts, for 200 seconds while the TCM is reporting the gear selector is in Park or Neutral.

1. The ECM does not illuminate the malfunction indicator lamp (MIL).
2. The ECM uses the transmission range data to enable engine cranking.
3. The ECM stores the operating conditions when the Conditions for Setting the DTC are met. This information is stored as a Failure Record.
4. The ECM stores DTC P0850 in ECM history.

1. The ECM clears the DTC from ECM history if the vehicle completes 40 warm-up cycles without a non emission diagnostic fault occurring.
2. The ECM cancels the default action when the ignition is OFF long enough in order to power down the ECM.
3. A scan tool can clear the DTC.

DTC P0850 (3.6L)

Scheme 83

The pressure control (PC) solenoid valve is located in the valve body. The PC solenoid valve controls transmission line pressure based on current flow through its windings. The transmission control module (TCM) determines desired line pressure based on throttle position and other inputs. The TCM then varies the duty cycle on the high side of the PC solenoid valve to control current flow to the solenoid. Current is controlled from about 0.02 amps for maximum line pressure to 1.1 amps for minimum line pressure. The TCM monitors the actual current to the solenoid.

If the TCM detects a commanded current draw that differs from the actual current draw by more than a calibrated value, then DTC P0961 sets. DTC P0961 is a type C DTC.

This diagnostic procedure supports the following DTC

DTC P0961 Line Pressure Control (PC) Solenoid System Performance

The PC solenoid valve is enabled.

DTC P0961 sets when the duty cycle is outside the range of 0.5-95 percent for 4 seconds.

1. The TCM does not illuminate the malfunction indicator lamp (MIL).
2. The TCM commands maximum line pressure.
3. The TCM freezes transmission adaptive functions.
4. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
5. The TCM stores DTC P0961 in TCM history.

Conditions for Clearing the DTC

1. A scan tool can clear the DTC.
2. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
3. The TCM cancels the DTC default actions when the fault no longer exists and the DTC passes.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step verifies that the fault is present.
2. 3: This step tests the transmission wiring harness and the PC solenoid valve for correct resistance.
3. 9: This step begins diagnosis of the engine side of the circuit.

DTC P0961 (3.6L)

Scheme 84

The 1-2 shift solenoid (1-2 SS) valve controls transmission fluid pressure acting on the 1-2 shift valves to position the valves for the appropriate gear. The 1-2 SS valve is a normally-open exhaust valve located on the control valve body. A fused circuit supplies ignition voltage to the 1-2 SS valve. The transmission control module (TCM) commands the solenoid ON or OFF by switching the ground path. When the 1-2 SS valve is commanded ON, the TCM senses low voltage. When the 1-2 SS valve is commanded OFF, the TCM senses high voltage. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects a continuous open or short to ground in the 1-2 SS valve circuit, then DTC P0973 sets. DTC P0973 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P0973 1-2 Shift Solenoid (SS) Control Circuit Low Voltage

The ignition is ON.

The TCM detects an open or short to ground in the 1-2 SS valve circuit for 4.4 seconds.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM commands maximum line pressure.
3. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
4. The TCM freezes transmission adaptive function.
5. The TCM inhibits 3-2 downshifts when the vehicle speed is greater than 52 km/h (32 mph).
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
7. The TCM stores DTC P0973 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections .

The number below refers to the step number on the diagnostic table.

1. 2: A short to ground in the ignition 1 voltage circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but, would set the other DTCs.

DTC P0973 (3.6L)

The 1-2 shift solenoid (1-2 SS) valve controls transmission fluid pressure acting on the 1-2 shift valves to position the valves for the appropriate gear. The 1-2 SS valve is a normally-open exhaust valve located on the control valve body. A fused circuit supplies ignition voltage to the 1-2 SS valve. The TCM commands the solenoid ON or OFF by switching the ground path. When the 1-2 SS valve is commanded ON, the TCM senses low voltage. When the 1-2 SS valve is commanded OFF, the TCM senses high voltage. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects a short to voltage in the 1-2 SS valve circuit, then DTC P0974 sets. DTC P0974 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P0974 1-2 Shift Solenoid (SS) Control Circuit High Voltage

The ignition is ON.

The TCM detects a short to voltage in the 1-2 SS valve control circuit for 4.4 seconds.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM commands maximum line pressure.
3. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
4. The TCM freezes transmission adaptive function.
5. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
6. The TCM stores DTC P0974 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections .

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step tests the TCM and the wiring to the transmission.
2. 5: This step verifies that the circuit has the correct resistance.

DTC P0974 (3.6L)

Scheme 85

The 2-3 shift solenoid (2-3 SS) valve controls transmission fluid pressure acting on the 1-2 and 2-3 shift valves to position the valves for the appropriate gear. The 2-3 SS valve is a normally-open exhaust valve located on the control valve body. A fused circuit supplies ignition voltage to the 2-3 SS valve. The transmission control module (TCM) commands the solenoid ON or OFF by switching the ground path. When the 2-3 SS valve is commanded ON, the TCM senses low voltage. When the 2-3 SS valve is commanded OFF, the TCM senses high voltage. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects an open or short to ground in the 2-3 SS valve circuit, then DTC P0976 sets. DTC P0976 is a type A DTC.

This diagnostic procedure supports the following DTC

DTC P0976 2-3 Shift Solenoid (SS) Control Circuit Low Voltage

The ignition is ON.

The TCM detects an open or short to ground in the 2-3 SS valve circuit for 4.4 seconds.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
2. The TCM commands maximum line pressure.
3. The TCM commands a soft landing to 2nd gear.
4. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
5. The TCM freezes transmission adaptive functions.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
7. The TCM stores DTC P0976 in TCM history.

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections .

The number below refers to the step number on the diagnostic table.

1. 2: A short to ground in the ignition 1 voltage circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but, would set the other DTCs.

DTC P0976 (3.6L)

The 2-3 shift solenoid (2-3 SS) valve controls transmission fluid pressure acting on the 1-2 and 2-3 shift valves to position the valves for the appropriate gear. The 2-3 SS valve is a normally-open exhaust valve located on the control valve body. A fused circuit supplies ignition voltage to the 2-3 SS valve. The TCM commands the solenoid ON or OFF by switching the ground path. When the 2-3 SS valve is commanded ON, the TCM senses low voltage. When the 2-3 SS valve is commanded OFF, the TCM senses high voltage. Refer to Shift Solenoid Valve State and Gear Ratio .

If the TCM detects a short to voltage in the 2-3 SS valve circuit, then DTC P0977 sets. DTC P0977 is a type A DTC.

This diagnostic procedure supports the following DTC

DTC P0977 2-3 Shift Solenoid (SS) Control Circuit High Voltage

The ignition is ON.

The TCM detects a short to voltage in the 1-2 SS valve circuit for 4.4 seconds.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
2. The TCM commands maximum line pressure.
3. The TCM inhibits 4th gear.
4. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
5. The TCM freezes transmission adaptive functions.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Freeze Frame and Failure Records.
7. The TCM stores DTC P0977 in TCM history.

1. The ECM turns OFF the MIL after the third consecutive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the MIL/DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Ensure the wiring harness is not stretched too tightly or other components are pressing on the A/T inline 20-way connector body. Also inspect for proper clearance to any other components and wiring. Refer to Testing for Intermittent Conditions and Poor Connections .

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step tests the TCM and the wiring to the transmission.
2. 5: This step verifies that the circuit has the correct resistance.

DTC P0977 (3.6L)

Scheme 86

The transmission pressure is modified by an adaptive modifier which controls the shift execution time. This diagnostic tests the time required to accomplish the shift. If the shift takes longer than 0.65 seconds and the adaptive modifier cannot shorten this time, then a counter increases by one.

If the TCM detects a counter value of 2 during one trip, then DTC P1811 sets. DTC P1811 is a type C DTC.

This diagnostic procedure supports the following DTC

DTC P1811 Maximum Adapt and Long Shift

1. The shift is adaptable.
2. The 1-2, the 2-3 or the 3-4 shift adapt cell has reached its limit.

The 1-2, 2-3 or 3-4 shift is longer than 0.65 seconds, twice in one trip.

1. The TCM does not request the ECM to illuminate the malfunction indicator lamp (MIL).
2. The TCM commands maximum line pressure.
3. The TCM freezes transmission adaptive functions.
4. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
5. The TCM stores DTC P1811 in TCM history.

1. A scan tool can clear the DTC.
2. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
3. The TCM cancels the DTC default actions when the fault no longer exists and the DTC passes.

1. Ask the customer about possible overloading, exceeding the trailer towing limit or towing in overdrive.
2. Ensure that the current TCM calibration is correct for the final drive ratio.

The numbers below refer to the step numbers on the diagnostic table.

1. 7: This step inspects components that may cause low line pressure.
2. 9: This step inspects or repairs components that may cause a maximum adapt and long 1-2 upshift.
3. 11: This step inspects or repairs components that may cause a maximum adapt and long 2-3 upshift.
4. 13: This step inspects or repairs components that may cause a maximum adapt and long 3-4 upshift.

DTC P1811 (3.6L)

The transmission pressure is modified by an adaptive modifier which controls the shift execution time. This diagnostic tests the time required to accomplish the shift. If the shift takes longer than 0.65 seconds and the adaptive modifier cannot shorten this time, then a counter increases by one.

If the PCM detects a counter value of 2 during one trip, then DTC P1811 sets. DTC P1811 is a type C DTC.

This diagnostic procedure supports the following DTC

DTC P1811 Maximum Adapt and Long Shift

1. The shift is adaptable.
2. The 1-2, the 2-3 or the 3-4 shift adapt cell has reached its limit.

The 1-2, 2-3 or 3-4 shift is longer than 0.70 seconds, twice in one trip.

1. The PCM does not illuminate the malfunction indicator lamp (MIL).
2. The PCM commands maximum line pressure.
3. The PCM freezes transmission adaptive functions.
4. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
5. The PCM stores DTC P1811 in PCM history.

1. A scan tool can clear the DTC.
2. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
3. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

1. Ask the customer about possible overloading, exceeding the trailer towing limit or towing in overdrive.
2. Ensure that the current PCM calibration is correct for the final drive ratio.

The numbers below refer to the step numbers on the diagnostic table.

1. 7: This step inspects components that may cause low line pressure.
2. 9: This step inspects or repairs components that may cause a maximum adapt and long 1-2 upshift.
3. 11: This step inspects or repairs components that may cause a maximum adapt and long 2-3 upshift.
4. 13: This step inspects or repairs components that may cause a maximum adapt and long 3-4 upshift.

DTC P1811 (3.8L)

Scheme 87

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The four inputs to the PCM indicate the position of the transmission range selector. The input voltage level at the PCM is high, B+, when the IMS is open and low when the switch is closed to ground. The four input parameters represented are Signals A, B, C and P - Parity. Refer to Transmission Internal Mode Switch Logic .

If the PCM detects a combination of IMS signals that do not indicate PARK or NEUTRAL while attempting to start the vehicle, then DTC P1819 sets. DTC P1819 is a type C DTC.

This diagnostic procedure supports the following DTC

DTC P1819 Internal Mode Switch - No Start/Wrong Range

1. The engine speed is 10 RPM or less.
2. The ignition switch is in the CRANK position.

The PCM detects a combination of IMS signals that do not indicate PARK or NEUTRAL when attempting to start the vehicle for 0.5 seconds.

1. The PCM does not illuminate the malfunction indicator lamp (MIL).
2. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
3. The PCM stores DTC P1819 in PCM history.

1. A scan tool can clear the DTC.
2. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
3. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

The numbers below refer to the step numbers on the diagnostic table.

1. 3: HI values for all signals in both Park and Drive 4 indicates the ground circuit is OPEN.
2. 5: With the 20-way connector disconnected, all signals should indicate HI.
3. 7: If one circuit affects the other, this indicates a short between the two circuits.
4. 13: This step tests the internal transmission harness. If no fault is found in the harness, the fault will be in the switch.

DTC P1819 (3.8L)

Scheme 88

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The four inputs to the transmission control module (TCM) indicate the position of the transmission range selector. The input voltage level at the TCM is high, B+, when the IMS is open and low when the switch is closed to ground. The four input parameters represented are Signals A, B, C and P - Parity. Refer to Transmission Internal Mode Switch Logic .

If the TCM detects that IMS Signal A is always low, then DTC P1820 sets. DTC P1820 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P1820 Internal Mode Switch A Circuit Low Voltage

1. The engine speed is greater than 500 RPM for 5 seconds.
2. No engine torque malfunction.
3. The engine torque is 50 N.m (37 lb ft) or more.
4. The IMS indicates PARK for 1 second or more.

The IMS Signal A is continuously low this ignition cycle and the IMS indicates transitional position D4-D3 for 8 seconds or more.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM commands maximum line pressure.
3. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
4. The TCM freezes transmission adaptive functions.
5. The TCM assumes D4 for shifting.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
7. The TCM stores DTC P1820 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send an MIL illumination request.
2. A scan tool can clear the DTC.
3. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

The numbers below refer to the step numbers on the diagnostic table.

1. 3: A low value for Signal A indicates a short to ground in the engine harness or the TCM.
2. 5: This step tests the internal transmission harness. A value of LOW for Signal A indicates the fault is in the harness. Otherwise the fault will be in the switch.

DTC P1820 (3.6L)

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The four inputs to the PCM indicate the position of the transmission range selector. The input voltage level at the PCM is high, B+, when the IMS is open and low when the switch is closed to ground. The four input parameters represented are Signals A, B, C and P - Parity. Refer to Transmission Internal Mode Switch Logic .

If the PCM detects that IMS Signal A is always low, then DTC P1820 sets. DTC P1820 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P1820 Internal Mode Switch A Circuit Low Voltage

1. No MAP DTC P0107 or P0108.
2. The engine torque is 55-407 N.m (40-300 lb ft).
3. The engine is running for greater than 5 seconds and not in fuel cut off.
4. The IMS indicates PARK for 2 seconds.

The IMS Signal A is continuously low this ignition cycle and the IMS indicates transitional position D4-D3 for 8 seconds.

1. The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes transmission adaptive functions.
4. The PCM assumes D4 for shifting.
5. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
6. The PCM stores DTC P1820 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

The numbers below refer to the step numbers on the diagnostic table.

1. 3: A low value for Signal A indicates a short to ground in the engine harness or the PCM.
2. 5: This step tests the internal transmission harness. A value of LOW for Signal A indicates the fault is in the harness. Otherwise the fault will be in the switch.

DTC P1820 (3.8L)

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The four inputs to the TCM indicate the position of the transmission range selector. The input voltage level at the TCM is high, B+, when the IMS is open and low when the switch is closed to ground. The four input parameters represented are Signals A, B, C and P - Parity. Refer to Transmission Internal Mode Switch Logic .

If the TCM detects that IMS Signal B is always high, then DTC P1822 sets. DTC P1822 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P1822 Internal Mode Switch B Circuit High Voltage

1. The engine speed is greater than 500 RPM for 5 seconds.
2. No engine torque malfunction.
3. The engine torque is 50 N.m (37 lb ft) or more.
4. The IMS indicates PARK for 1 second or more.

The IMS Signal B is continuously high this ignition cycle and the IMS indicates transitional position D2-D1 for 8 seconds or more.

1. The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL) during the consecutive trip in which the Conditions for Setting the DTC are met.
2. The TCM commands maximum line pressure.
3. The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
4. The TCM freezes transmission adaptive functions.
5. The TCM assumes D4 for shifting.
6. The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
7. The TCM stores DTC P1822 in TCM history during the consecutive trip in which the Conditions for Setting the DTC are met.

1. A scan tool can clear the DTC.
2. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
3. The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

The number below refers to the step number on the diagnostic table.

1. 3: This step tests the integrity of the engine harness and TCM by checking for the Signal B state change from HI to LOW. A LOW signal indicates the fault is either in the internal transmission harness or the switch. A HI signal indicates the fault is either in the engine harness or the TCM.

DTC P1822 (3.6L)

The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The four inputs to the PCM indicate the position of the transmission range selector. The input voltage level at the PCM is high, B+, when the IMS is open and low when the switch is closed to ground. The four input parameters represented are Signals A, B, C and P - Parity. Refer to Transmission Internal Mode Switch Logic .

If the PCM detects that IMS Signal B is always high, then DTC P1822 sets. DTC P1822 is a type B DTC.

This diagnostic procedure supports the following DTC

DTC P1822 Internal Mode Switch B Circuit High Voltage

1. No MAP DTC P0107 or P0108.
2. The engine torque is 55-407 N.m (40-300 lb ft).
3. The engine is running for greater than 5 seconds and not in fuel cut off.
4. The IMS indicates PARK for 2 seconds.

The IMS Signal B is continuously high this ignition cycle and the IMS indicates transitional position D2-D1 for 8 seconds.

1. The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes transmission adaptive functions.
4. The PCM assumes D4 for shifting.
5. The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
6. The PCM stores DTC P1822 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

1. The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
2. A scan tool can clear the MIL/DTC.
3. The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
4. The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

The number below refers to the step number on the diagnostic table.

1. 3: This step tests the integrity of the engine harness and PCM by checking for the Signal B state change from HI to LOW. A LOW signal indicates the fault is either in the internal transmission harness or the switch. A HI signal indicates the fault is either in the engine harness or the PCM.

DTC P1822 (3.8L)

See also:
• Shift Solenoid Valve State and Gear Ratio
• Diagnostic System Check - Vehicle
• Transmission Fluid Checking Procedure
• Shift Solenoid Leak Test
• Symptoms - Automatic Transmission
• CONTROL VALVE BODY DISASSEMBLE (WITHOUT TOUCH
• Diagnostic Trouble Code (DTC) List - Vehicle
• Testing for Intermittent Conditions and Poor Connections
• Circuit Testing
• Wiring Repairs
• Testing for Short to Ground
• Testing for Continuity
• Special Tools
• Automatic Transmission Inline 20-Way Connector End View (3.6L)
• Wiring Harness Replacement
• Control Module References
• Torque Converter Replacement Guide
• Diagnostic Trouble Code (DTC) List/Type
• Testing for a Short to Voltage
• Incorrect Line Pressure
• Transmission Internal Mode Switch Logic
• Automatic Transmission Range Selector Cable Adjustment