4L80-E / 4L85-E Automatic Transmission

DTC P0758

Test 1-4:

Test 5-12:

Test 13-20:

Test 21-22:

Circuit Description with 4L80-E / 4L85-E Automatic Transmission
The 2-3 shift solenoid (SS) valve controls fluid of the 2-3 shift valve. The 2-3 SS valve is a normally-open exhaust valve used with the 1-2 SS valve in order to allow four different shifting combinations. The 2-3 SS valve attaches to the control valve body within the transmission. The ignition voltage goes directly to the 2-3 SS valve. The powertrain control module (PCM) controls the 2-3 SS valve by providing a ground path through the 2-3 shift solenoid valve control circuit.

If the PCM detects a continuous open or short in the 2-3 SS valve circuit or the 2-3 SS valve, then DTC P0758 sets. DTC P0758is a type C DTC. For California emissions vehicles and vehicles under 8,600 G.V.W.. DTC P0758is a type A DTC.

Conditions for Running the DTC
The engine is running more than 400 RPM for greater than 7 seconds.

Conditions for Setting the DTC
One of the following conditions occur for 4.3 out of 5 seconds.
^ The PCM commands the 2-3 SS valve ON, and the voltage input remains high, B+.
^ The PCM commands the 2-3 SS valve OFF, and the voltage input remains low, 0 volts.

Action Taken When the DTC Sets
^ The PCM illuminates the malfunction indicator lamp (MIL) for California emission vehicles.
^ The PCM commands a soft landing to second gear.
^ The PCM commands maximum line pressure.
^ The PCM freezes transmission adaptive function.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame, California only, and Failure Records, California and Federal.
^ The PCM stores DTC P0758 in PCM history.

Conditions for Clearing the MIL/DTC
^ For 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 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 Federal emissions, 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
DTC P0758 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine. Refer to Shift Solenoid Valve State and Gear Ratio.

Test Description
The numbers refer to the step numbers on the diagnostic table.
4. This step tests the function of the 2-3 SS valve and the internal wiring harness.
5. This step tests the power to the 2-3 SS valve from the ignition through the fuse.
6. This step tests the ability of the PCM and the wiring to control the ground circuit.
8. This step measures the resistance of the automatic transmission (AT) wiring harness assembly and the 2-S SS valve.