P0753

Shift Solenoid Valve State And Gear Ratio:

Circuit Description
The 1.2 Shift Solenoid Valve Assembly (1-2 SS Valve Assy.) controls the transmission fluid pressure on the 1-2 shift valve. Circuit 1339 provides ignition voltage to the solenoid. The Output Driver Module (ODM), within the Powertrain Control Module (PCM), commands the solenoid ON and OFF by closing and opening the ground. The PCM monitors voltage levels at the ODM. When the 1-2 SS Valve Assy. is commanded ON, the PCM detects a low voltage. When the 1-2 SS Valve Assy. is commanded OFF, the PCM detects a high voltage.

DTC P0753 sets if the received voltage is outside the calibration limits, indicating an open or short to ground. DTC P0753 is a type A DTC.

Conditions for Setting the DTC
^ System voltage is 10-16 volts.
^ The engine speed is greater than 500 RPM.
^ Not in fuel shut off.
^ The PCM commands the solenoid ON and the voltage signal to the PCM remains high (B+).
^ The PCM commands the solenoid OFF and the voltage signal to the PCM remains low (0 volts).
^ All conditions are met for 5 seconds.

Action Taken When the DTC Sets
^ The PCM illuminates the Malfunction Indicator Lamp (MIL).
^ The PCM inhibits downshifts to 2nd gear if the vehicle speed is greater than 48 km/h (30 mph).

Conditions for Clearing the MIL/DTC
^ The PCM turns OFF the MIL after three consecutive trips without a failure reported.
^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

Diagnostic Aids
^ Inspect the wiring at the PCM, the transmission connector, 1-2 shift solenoid connector and all other circuit connecting points for the following conditions:
- A bent terminal
- A backed out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation
- Moisture intrusion
- Corrosion
^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
^ Ensure that the scan tool commanded gear has correct solenoid states and ratio. Refer to Shift Solenoid Valve State and Gear Ratio table.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
6. This step isolates the fault between the engine harness and the transmission harness.
8. This step verifies that circuit 1222 is neither open nor shorted to power.
11. This step verifies that the 1-2 shift solenoid has neither shorted across its windings nor increased its resistance.