Component Tests and General Diagnostics

Before beginning diagnosis, make a visual inspection for the following and repair as needed:

1. Disconnected or damaged wiring.
2. Pinched, cracked, plugged, or disconnected vacuum hoses.
3. Binding or misadjusted throttle to servo linkage.

If the visual inspection shows no fault, check the operation of the electrical and vacuum release switches.

ELECTRICAL RELEASE SWITCH CHECK
1. Set ignition to "ON"; set cruise control "OFF-ON" switch to "ON." Install Tech 1.
2. View Torque Converter Clutch (TCC) brake switch, status should be correct with brake pedal applied and released. If not, refer to DTC P0703 TCC Brake Input Circuit chart in Computers and Control Systems / Systems Diagnosis / Diagnostic Charts, for diagnosis. Testing and Inspection
3. View Cruise Control (C/C) brake switch, status should be correct with brake pedal applied and released. If the switch status changes, the electrical release switch is OK.
4. If C/C brake switch status is incorrect, probe CKT 397 with a test light to ground. If the test light does not light, refer to Chart C-17 Cruise Control System Check. If the test light does turn "ON," continue to Step 5. Testing and Inspection
5. Jumper CKTs 86 and 397 at the cruise control brake switch. If the Tech 1 display switches from "RELEASED" to "APPLIED" as the circuits are jumpered, adjust or replace the brake switch as needed.
6. If the switch status does not change when the wires are jumpered, the problem is CKT 86 open or shorted between the brake switch and PCM, a poor connection at the PCM or a faulty PCM.