DTC 90

Diagnostic Trouble Code (DTC) 90:

Torque Converter Clutch Solenoid Circuit:

CIRCUIT DESCRIPTION
The Torque Converter Clutch (TCC) solenoid is an electrical device used to control fluid acting on the TCC converter clutch valve, which then controls TCC apply and release. The Powertrain Control Module (PCM) monitors Throttle Position (TP) voltage, vehicle speed and other inputs to determine when to energize the TCC solenoid. Ignition voltage is supplied directly to the TCC solenoid. The Powertrain Control Module (PCM) controls the solenoid by providing the ground path through CKT 422.

DTC 90 WILL SET WHEN:
The PCM commands the TCC solenoid "ON" and the voltage stays high (B+) for 2 seconds. The PCM commands the TCC solenoid "OFF" and the voltage drops to zero volts for 2 seconds.

ACTION TAKEN (PCM will default to):
No TCC will occur, and no fourth gear if in hot mode. DTC 90 will be stored in the PCM memory but will not turn "ON" the Malfunction Indicator Lamp (MIL).

DTC 90 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 for a shorted, internal transmission harness or TCC solenoid.
2. This test checks power supply to the TCC solenoid.

DIAGNOSTIC AIDS
Check all connections at the transmission pass-thru connector.

Some slight TCC slip is normal.

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