DTC 90

DTC 90 Chart:

Torque Converter Clutch (TCC) Circuit:

CIRCUIT DESCRIPTION
The torque management brake switch contains two sets of electrical contacts and one vacuum port. The two sets of electrical contacts are normally closed and referred to as the "TCC Brake" and "Extended Travel Brake Switch" contacts. The Torque Converter Control (TCC) brake switch contacts provide ignition voltage to the torque converter clutch when closed (brakes not applied). When the brake pedal is depressed, the switch contacts open and the Powertrain Control Module (PCM) opens the path to ground for the TCC electrical circuit to release the TCC.

DTC 90 WILL SET WHEN
- No DTCs 33, 106, 133 or 137.
- Traction control or ABS system operating normally.
- Non-drive wheel speed of 36 mph or greater.
OR
Non-drive wheel speed of 36 mph or greater and has not fallen below 1.2 mph since.
- A 2.5 mph or greater decrease in non drive wheel speed in 0.2 second.
- Transition in the extended travel brake contacts of the torque management brake switch with no transition notice in the TCC brake switch contacts.
- All conditions must be met 5 times.

ACTION TAKEN (PCM WILL DEFAULT TO)
- DTC 90 does not illuminate the Malfunction Indicator Lamp (MIL) (Service Engine Soon).
- Disable traction control.
- The PCM will substitute the status of the stop/BTSI/cruise brake switch input for the torque management brake switch input.
- Shift adapts are maintained at current levels.

DTC 90 WILL CLEAR WHEN
The fault no longer exists and the ignition switch is cycled "OFF" and "ON."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test checks for power to the switch.
2. This test checks the switch.

DIAGNOSTIC AIDS
This test functions on the assumption that a sudden decrease in vehicle speed must be accompanied by a brake application. If there is a sudden decrease in vehicle speed and a transition on the extended travel brake switch is noticed without a transition on the TCC brake switch then the TCC brake switch in considered failed.