P0753

Circuit Description

The 1 - 2 shift solenoid (SS) valve controls the fluid flow acting on the 1 - 2 and 3 - 4 shift valves. The 1 - 2 SS valve is a normally-open exhaust valve that is used with the 2 - 3 SS valve in order to allow four different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 1 - 2 SS valve receives ignition voltage through circuit 239. The powertrain control module (PCM) controls the solenoid by providing the ground path on circuit 1222.

When the PCM detects a continuous open or 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 B DTC.

Conditions for Running the DTC

^ The system voltage is 9-18 volts.
^ Engine speed is greater than 450 RPM for 5 seconds.
^ The engine is not in fuel cutoff.

Conditions for Setting the DTC

DTC P0753 sets if either of the following conditions occurs for 5 seconds:

^ The PCM commands the solenoid ON and the voltage input remains high (B+).
^ The PCM commands the solenoid OFF and the voltage input remains low (0 volts).

Action Taken When the DTC Sets

^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the conditions for setting the DTC are met.
^ The PCM commands D2 line pressure.
^ The PCM inhibits 3 - 2 downshifts if the vehicle speed is greater than 48 km/h (30 mph).
^ The PCM freezes shifts adapts from being updated.
^ The PCM stores DTC P0753 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

Conditions for Clearing the MIL/DTC

^ The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ A scan tool clears the DTC from PCM history.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids

^ Inspect the wiring at the PCM, the transmission connector and all other circuit connecting points for the following conditions:
- A backed out terminal
- A damaged terminal
- Reduced 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.
^ An open ignition feed circuit can cause multiple DTCs to set.
^ Refer to the Shift Solenoid Valve State and Gear Ratio table.

Test Description

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

4. This step tests the function of the 1 - 2 SS valve and the automatic transmission (A/T) wiring harness assembly.
5. This step tests for power to the 1 - 2 SS valve from the ignition through the fuse.
7. This step tests the ability of the PCM and the wiring to control the ground circuit.
10. This step measures the resistance of the A/T wiring harness assembly and the 1 - 2 SS valve.