P0977

DTC P0977





Circuit Description
The 2-3, 3-4 shift solenoid (SS) valve (S2) controls transmission fluid pressure acting on the M2 shift valve to position the valve for the appropriate gear. The 2-3, 3-4 SS valve (S2) is a normally open exhaust valve located on the front control valve body. The solenoid is case grounded. The output driver module (ODM), within the transmission control module (TCM), commands the solenoid ON or OFF by providing voltage. When the 2-3, 3-4 SS valve (S2) is commanded ON, the TCM senses high voltage. When the 2-3, 3-4 SS valve (S2) is commanded OFF, the TCM senses low voltage.

If the TCM detects a continuous open or short to voltage in the 2-3, 3-4 SS valve (S2) circuit, then DTC P0977 sets. DTC P0977 is a type A DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:

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

Conditions for Running the DTC
^ The system voltage is 10.2 - 15.5 volts.
^ The engine speed is greater than 400 RPM.
^ Trans. Protection Mode is OFF.
^ The TCM has commanded the 2-3, 3-4 SS valve OFF.

Conditions for Setting the DTC
The 2-3, 3-4 SS valve (S2) feedback circuit indicates a continuous open or short to voltage for 0.5 seconds.

Action Taken When the DTC Sets
^ The TCM requests the powertrain control module (PCM) to illuminate the malfunction indicator lamp (MIL).
^ The TCM turns the Trans. Protection Mode ON.
^ The transmission will operate in 4th gear when the transmission is shifted into D.
^ The line pressure is at maximum.
^ The torque converter clutch (TCC) is disabled.
^ The TCM freezes the transmission adaptive functions.
^ The TCM disables engine bracking.
^ 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.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Record.
^ The TCM stores DTC P0977 in TCM history.

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

Test Description

Step 1 - Step 7:

Step 8 - Step 13:

The numbers below refer to the step numbers on the diagnostic table.
5. This step determines if the shift solenoid has a poor ground connection.