P0748
DTC P0748
Circuit Description
The pressure control (PC) solenoid valve regulates actuator feed fluid passing through the solenoid into torque signal pressure. The TCM uses a pulse width modulated signal in order to control the torque signal pressure. The TCM compares various inputs in order to determine the appropriate pressure for a given load. The TCM varies the current to the PC solenoid from 0.1 amps, for maximum line pressure to 1.1 amps, for minimum line pressure. An internal current monitor within the TCM provides feedback in order to determine actual PC solenoid valve current draw.
If the TCM detects a continuous open, short to voltage or short to ground in the PC solenoid circuit, then DTC P0748 sets. DTC P0748 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0748 Pressure Control (PC) Solenoid Control Circuit
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The PC solenoid valve feedback circuit indicates a continuous open or short to ground for greater than 1.2 seconds.
Action Taken When the DTC Sets
* The TCM does not request the ECM to illuminate the malfunction indicator lamp (MIL).
* The TCM commands maximum line pressure.
* 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 a Failure Record.
* The TCM stores DTC P0748 in TCM history.
Conditions for Clearing the DIC/DTC
* The TCM clears the DIC when the condition no longer exists.
* A scan tool can clear the DTC.
* The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
* The TCM cancels the DTC default actions when the ignition 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.
2. This step verifies the ability of the TCM to command the PC solenoid valve.
3. This step verifies that the automatic transmission wiring harness and the PC solenoid have correct resistance.
Step 1 - Step 5:
Step 6 - Step 10:
Step 11 - Step 16:
