P0973

DTC P0973





Circuit Description

The 1-2 shift solenoid (SS) valve controls transmission fluid pressure acting on the 1-2 and 3-4 shift valves to position the valves for the appropriate gear. The 1-2 SS valve is a normally open exhaust valve located on the lower control valve body. Ignition voltage is supplied to the solenoid. The transmission control module (TCM) commands the solenoid ON or OFF by providing a 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.

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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

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

Conditions for Running the DTC

The engine is running for 5 seconds.

Conditions for Setting the DTC

The 1-2 SS valve feedback circuit indicates a continuous open or short to ground for 4.4 seconds.

Action Taken When the DTC Sets

^ The TCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
^ The TCM commands maximum line pressure.
^ The TCM inhibits 3-2 downshifts above 52 km/h (32 mph).
^ The TCM freezes transmission adaptive functions.
^ 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.
^ The TCM stores DTC P0973 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

^ The TCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ 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

The numbers below refer to the step numbers on the diagnostic table.
8. This step tests the electrical operation of the solenoid.
9. This step tests the TCM and the wiring to the transmission.
14. This step verifies that the circuit has the correct resistance.

Step 1 - Step 5:

Step 6 - Step 12:

Step 13 - Step 19: