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 powertrain control module (PCM) commands the solenoid ON or OFF by providing a 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.
If the PCM 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 run time is greater than 5 seconds.
Conditions for Setting the DTC
The 1-2 SS valve feedback circuit indicates a continuous open or short to ground for 4.3 seconds.
Action Taken When the DTC Sets
* The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
* The PCM commands maximum line pressure.
* The PCM inhibits 4th gear when in hot mode.
* The PCM freezes transmission adaptive functions.
* 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 PCM stores DTC P0973 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the MIL/DTC
* The PCM 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 PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
* The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.
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 PCM and the wiring to the transmission.
14. This step verifies that the circuit has the correct resistance.
Step 1 - Step 8:
Step 9 - Step 16:
