P0753

Diagnostic Chart:

Wiring Diagram:

Description:

Circuit Description

The 1-2 Shift Solenoid Valve (1-2 SS Valve) controls fluid flow acting on the 1-2 shift valve. The solenoid is a normally-open valve that, in conjunction with the 2-3 Shift Solenoid Valve (2-3 SS Valve), allows four different shifting combinations (Refer to the 4T40-E Shift Solenoid State chart). The 1-2 SS Valve is attached to the valve body, within the transmission. The solenoid receives ignition voltage through the fused circuit. The Powertrain Control Module (PCM) commands the solenoid ON or OFF by providing a ground path through circuit 1222.

When the PCM detects a continuous open, short to ground, or short to power in the 1-2 SS Valve circuit, then DTC P0753 sets. DTC P0753 is a type A DTC.

Conditions for Setting the DTC

^ The ignition switch is in the RUN position.

^ The PCM commands the solenoid ON, and the voltage remains high for 4.3 seconds.

Action Taken When the DTC Sets

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ The PCM freezes shift adapts from being updated.

^ The PCM commands maximum line pressure.

^ The PCM inhibits TCC engagement.

^ The PCM commands a soft landing to 2nd gear.

^ DTC P0753 is stored in the PCM history.

Conditions for Clearing the MIL/DTC

^ The PCM turns OFF the MIL after three consecutive ignition cycles 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

^ An open in circuit 439 will cause multiple DTCs to set.

^ Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look 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 When diagnosing for an intermittent short or open condition massage the wiring harness while watching the test equipment for a change.

Test Description

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

2. DTCs P0719, P0724, and P0758 set if the power circuit is open.

8. This Step tests the electrical operation of the solenoid.

9. This Step tests the PCM and the wiring to the transmission.

15. This Step tests circuit 1222 for a short to battery power.

17. This Step verifies that the circuit has the correct resistance.