P0753

Circuit Description
The 1-2 shift solenoid (1-2 SS) valve controls the fluid flow acting on the 1-2 and the 3-4 shift valves. The 1-2 SS valve is a normally-open exhaust valve that is used with the 2-3 shift solenoid (2-3 SS) valve in order to allow four different shifting combinations.

The 1-2 SS valve attaches to the control valve body within the transmission. The ignition voltage goes directly to the 1-2 SS valve. The Powertrain Control Module (PCM) controls the 1-2 SS valve by providing the ground path through circuit 1222.

If 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 A DTC.

Conditions for Running the DTC
^ The engine runs more than 475 RPM for greater than 7 seconds.
^ System voltage is 8.0-18.0 volts.

Conditions for Setting the DTC
The above conditions are met and either of the following conditions occur for 4.3 out of 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).
^ The PCM commands maximum line pressure.
^ The PCM freezes shift adapts.
^ The PCM stores DTC P0753 in PCM history.

Conditions for Clearing the MIL/DTC
^ For Federal and California emissions, 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.
^ For Federal and California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without an emission related diagnostic fault occurring.
^ For vehicles equal to or greater than 15,000 lbs GVW, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without a non-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 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, massage the wiring harness while watching the test equipment for a change.
^ An open ignition feed circuit can cause multiple DTCs to set.
^ First diagnose and clear any engine DTCs that are present. Then inspect for any transmission DTCs that may have reset.
^ Refer to 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 wiring harness assembly.
5. This step tests the 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 automatic transmission wiring harness assembly and the 1-2 SS valve.