4L80-E / 4L85-E Automatic Transmission

DTC P0753 (Diesel)















Circuit Description with 4L80-E / 4L85-E Automatic Transmission
The 1-2 Shift Solenoid (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 (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 B DTC.

Conditions for Running the DTC
^ The engine runs more than 475 RPM for greater than 7 seconds.
^ System voltage is 8-18 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 records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this in
formation as Freeze Frame and Failure Records.
^ 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 can clear the MIL/DTC.
^ For Federal and California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 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 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
^ An open ignition feed circuit can cause multiple DTCs to set.
^ Refer to Shift Solenoid Valve State and Gear Ratio table.
^ DTC P0753 defaults to an elevated line pressure condition which may result in TCC partial apply. This may induce idle surge and engine stall.

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.
10. This step measures the resistance of the 1-2 AA valve.