GM Service Manual Online
For 1990-2009 cars only

Circuit Description

INSERT GRAPHIC SMITL60592AB

3rd clutch is applied when circuit 1223 is opened at the PCM. When the PCM grounds the circuit the voltage is monitored at terminal J4A06 to check for proper circuit conditions.

Conditions for Setting the DTC

DTC P0763 is set when the PCM has detected voltage monitored at terminal J4A06 (circuit 1223) is greater than 2-2.5 volts, when the 3rd gear 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.

Conditions that set this DTC will probably result in a DTC P0782-3rd gear stuck ON and a DTC P0741-No TCC and P0732 no 2nd gear. These conditions will also cause 3rd gear starts.

Test Description

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

  1. This step verifies that the problem is still present.

  2. If the actuator, connector plate, or circuit 1223 is shorted, DTC P0763 will set. This step will break the circuit down to find the source of the short.

  3. If circuit 1223 is shorted to voltage, DTC P0763 will set. This step checks circuit 1223 for a short to voltage.

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


Object Number: 902786  Size: FP