GM Service Manual Online
For 1990-2009 cars only

Circuit Description

INSERT GRAPHIC SMITL65513AA

During normal driving modes the PCM/TC adapts line pressure to prevent clutch slip and harsh shifts. This is accomplished by modulating the transaxle fluid pressure (TFP) actuator ground (1530) to raise or lower pressure. Open circuit = high pressure, grounded circuit = low pressure. When the PCM opens the circuit the voltage is monitored to check for proper circuit conditions.

Conditions for Setting the DTC

DTC P0747 is set when the PCM has detected voltage monitored at terminal J4A03 (circuit 1530) is greater than 2-2.5 volts when the TFP actuator is switched ON electrically by the PCM, twice per ignition cycle.

Repair Verification

Monitor DTC Menu Code Status for Pass Since Code Clear and Pass This Ignition Cycle. When both have passed, the repair is verified.

Criteria for a pass:

    • The engine is running.
    • Power is present at the actuators and no active faults exist for this actuator.

Diagnostic Aids

When attempting to diagnose an intermittent problem use the scan tool* to review the supplemental diagnostic information. The supplemental data can be used to duplicate a problem.

*Select MALF History and DTC status from the DTC menu of the scan tool.

Check for tightness of the female terminal grip with a spare male terminal.

When the PCM detects a fault in the circuit (open, ground, short) the PCM will open the circuit internally to protect the circuit.

No 2nd, 3rd, 4th gear 732,733,734 DTCs set if circuit grounded: low line. Will not shift out of first.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies a problem is still present.

  2. If the TFP

    actuator, connector plate, or circuit 1530 is shorted, DTC P0747 will set. This step will break the circuit down to find the source of the short.

  3. If circuit 1530 is shorted to voltage, DTC P0747 will set. This step checks circuit 1530 for a short to voltage.

  4. This step will determine if it is the TFP actuator or the actuator connector plate that is shorted. An actuator is shorted internally when its resistance is one or more ohms lower than the average resistance of the other actuators at the same temperature.


Object Number: 903057  Size: FP