P0977
DTC P0977 (4.2L)
Circuit Description
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves. The solenoid is a normally-open exhaust valve. With the 1-2 SS valve, the 2-3 SS valve allows 4 different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 2-3 SS valve receives voltage through the ignition voltage circuit. The powertrain control module (PCM) controls the solenoid by providing the ground path on the 2-3 SS valve control circuit.
When the PCM detects a continuous short to voltage in the 2-3 shift solenoid valve control circuit, then DTC P0977 sets. DTC P0977 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0977 2-3 Shift Solenoid (SS) Control Circuit High Voltage
Conditions for Running the DTC
The engine speed is greater than 475 RPM for 7 seconds.
Conditions for Setting the DTC
DTC P0977 sets if the PCM commands the solenoid ON and the voltage feedback remains high, B+.
Action Taken When the DTC Sets
- The PCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
- The PCM commands maximum line pressure.
- The PCM inhibits TCC engagement.
- The PCM freezes transmission adaptive functions.
- At the time of the first failure, the PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as a Failure Record.
- At the time of the second failure, the ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame.
- The PCM stores DTC P0977 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the DTC
- The ECM turns OFF the MIL after the third consecutive drive trip in which the PCM does not send a MIL illumination request.
- A scan tool can clear the DTC.
- The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
- The PCM cancels the default actions when the ignition is OFF long enough in order to power down the PCM.
