Powertrain Controls - ECM/PCM

Diagnostic Chart:

CIRCUIT DESCRIPTION
Hydraulically, the 3-2 control solenoid coordinates the apply rate of the 2-4 band with the hydraulic release, of the 3-4 clutch during a 3-2 downshift.

The PCM continually monitors the 3-2 circuit duty cycle depending on the commanded state of the circuit.

When the transmission is in first gear the duty cycle of the solenoid is equal to 0. When the transmission is in second gear or higher the duty cycle of the solenoid will be about 90%. When the transmission downshifts, 3-2, the duty cycle of the solenoid will drop.

DTC 66 WILL SET WHEN
^ The PCM commands the solenoid "ON," and the voltage remains high (B+).
OR
^ The PCM commands the solenoid "OFF," and the voltage drops to zero volts.
^ All conditions met for 4 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
^ A delayed (soft) landing to third gear.
^ Maximum line pressure.

DTC 66 WILL CLEAR WHEN
The fault condition(s) no longer exist, and the ignition switch is cycled "OFF" then "ON."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks the function of the 3-2 control solenoid and the internal transmission harness.
2. This test checks for power to the 3-2 control solenoid from the ignition through the fuse.

DIAGNOSTIC AIDS
Check all connections at the transmission connector.

If OK, refer to "PCM Intermittent Diagnostic Trouble Codes or Performance" or "Symptom Diagnosis" in Transmission and Drivetrain. Transmission and Drivetrain

The 3-2 control solenoid feedback normally oscillates "ON"/"OFF" when the duty cycle is applied.

An open in the ignition feed circuit will cause multiple DTC(s) to set.