4L80-E / 4L85-E Automatic Transmission

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

Schematic:

Circuit Description with 4L80-E / 4L85-E Automatic Transmission
The 2-3 Shift Solenoid (2-3 SS) valve controls the fluid flow acting on the 2-3 shift valve. The 2-3 SS valve is a normally-open exhaust valve used with the 1-2 shift solenoid (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 the ground path through circuit 1223.

If the PCM detects a continuous open or short to ground in the 2-3 SS valve circuit or the 2-3 SS valve, then DTC P0758 sets. DTC P0758 is a type A DTC.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running greater than 475 RPM for greater than 7 seconds.
^ The system voltage is 8.0-18.0 volts.

CONDITIONS FOR SETTING THE DTC
The PCM detects either of the following fail conditions for 4.3 out of 5 seconds.
^ The PCM commands the solenoid ON and voltage input remains high (B+).
^ The PCM commands the solenoid OFF and voltage input remains low (0 volts).

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL).
^ The PCM commands an immediate landing to second gear.
^ 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 information as Freeze Frame and Failure Records.
^ The PCM stores DTC P0758 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
^ First diagnose and clear any engine DTCs that are present. Then inspect for any transmission DTCs that may have reset.
^ An open ignition feed circuit can cause multiple DTCs to set.
^ Refer to Shift Solenoid Valve State and Gear Ratio table.
^ Inspect the connectors at the PCM, the AT wiring harness and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Diagrams.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
4. This step tests the function of the 2-3 SS valve and the automatic transmission wiring harness assembly.
5. This step tests the power to the 2-3 SS valve from the ignition through the fuse.
10. This step measures the resistance of the 2-3 SS valve.