Diagnostic Aids

Perform this circuit test when directed by other CIRCUIT TESTS. This test is only intended to diagnose:

• Faulty Powertrain Control Module (PCM).
• Throttle plate linkage.

1) Check For Codes 23, 53, 63, 121, 122 & 123  Disconnect cruise control servo wiring harness connector (if equipped). Perform KOEO SELF-TEST. If Code 23, 53, 63, 121, 122 or 123 is present, go to appropriate CIRCUIT TEST. See SERVICE CODE-TO-TEST MENUS, and service codes as necessary. If Code 11/111 (pass code) is displayed, go to step 2). If no code is displayed, go to CIRCUIT TEST QA.

2) Check Throttle Linkage  Check throttle and linkage for sticking and binding. If throttle and linkage are okay, replace Throttle Position (TP) sensor and repeat QUICK TEST. If throttle and linkage are binding, repair as necessary and repeat QUICK TEST.