4L60-E / 4L65-E Automatic Transmission

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

Schematic:

CIRCUIT DESCRIPTION
The 1-2 Shift Solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows 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 1020. The Vehicle Control Module (VCM) controls the solenoid by providing the ground path on circuit 1222.

When the VCM detects a continuous open, short to ground or short to power in the 1-2 SS valve circuit, then DTC P0753 sets. DTC P0753 is a type A DTC.

CONDITIONS FOR RUNNING THE DTC
^ The system voltage is 10-19 volts.
^ The 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 one of the following conditions occurs for 5 seconds:

Condition 1
The VCM commands the solenoid ON and the voltage feedback remains high (B+).

Condition 2
The VCM commands the solenoid OFF and the voltage feedback remains low (0 volts).

ACTION TAKEN WHEN THE DTC SETS
^ The VCM illuminates the Malfunction Indicator Lamp (MIL).
^ The VCM commands D2 line pressure.
^ The VCM inhibits 3-2 downshifts if the vehicle speed is greater than 48 km/h (30 mph).
^ The VCM freezes shift adapts from being updated.
^ The VCM records the operating conditions when the Conditions for Setting the DTC are met. The VCM stores this information as Freeze Frame and Failure Records.
^ The VCM stores DTC P0753 in VCM history.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The VCM 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.
^ The VCM clears the DTC from VCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The VCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the VCM.

DIAGNOSTIC AIDS
^ Inspect the connectors at the VCM, the 1-2 SS valve 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.
^ 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 (AT) wiring harness assembly.
5. This step tests for power to the 1-2 SS valve from the ignition through the fuse.
6. This step tests the ability of the VCM and of the wiring to control the ground circuit.
8. This step measures the resistance of the AT wiring harness assembly and of the 1-2 SS valve.