P0753

Diagnostic Chart:

Diagnostic Chart (cont'd):

Diagnostic Chart (cont'd):

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The 1-2 Shift Solenoid Valve (1-2 SS Valve) controls the fluid flow acting on the 1-2 and 3-4 shift valve. The solenoid is a normally-open exhaust valve. The combination of the 2-3 Shift Solenoid Valve and the 1-2 SS Valve allows four different shifting combinations. The solenoid attaches to the control valve body within the transmission. Circuit 439 supplies ignition voltage directly to the 1-2 SS Valve. The PCM controls the solenoid by providing a ground path through circuit 1222.

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


CONDITIONS FOR SETTING THE DTC

- The ignition is ON.

- The system voltage is 10-17 volts.

- The PCM commands the solenoid ON and the voltage remains high (B+).

- The PCM commands the solenoid OFF and the voltage remains low (0 volts).

- All conditions met for 5 seconds

ACTION TAKEN WHEN THE DTC SETS

- The PCM commands maximum line pressure

- The PCM freezes shift adapts from being updated.

- If in hot mode, force the TCC on in 3rd and 4th gear when the brake is not applied and downshift is not requested.

- The PCM inhibits downshifts to 2nd when the speed is greater than 30 mph.

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


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

- Inspect the wiring for any poor electrical connections at the PCM. Inspect the wiring at the TCC brake switch. 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 th6 insulation

- When diagnosing for an intermittent short or an open condition massage the wiring harness while watching the test equipment for changes.

- An open feed circuit can set multiple DTCs.

TEST DESCRIPTION

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

4. Step 4 verifies that the 1-2 SS Valve and the Automatic Transmission wiring harness are functioning normally.

6. Step 6 verifies that the ignition supplies power to the 1-2 SS Valve through the PCM IGN fuse.

16. Step 16 verifies that the valve's resistance is within specifications.