Diagnosis & Repair Procedure
NOTE:
For better performance and results of this diagnostic procedure, usage of appropriate wiring diagram is recommended. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS
article in ELECTRICAL.
NOTE:
Perform all voltage and resistance tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use an ohmmeter to isolate wiring harness shorts or opens.
- If engine system check has been performed, go to next step. If engine system check has not been performed, perform A-4: ENGINE SYSTEM CHECK under SYSTEM TESTS, then go to next step.
- Drive vehicle and check speedometer for vehicle speed indication. If speedometer indicates vehicle speed, go to next step. If speedometer does not indicates vehicle speed, turn ignition switch to LOCK position and check for open circuit in Blue/Yellow wire between ECM and VSS. If open circuit is found, repair as necessary and repeat DTC CONFIRMATION TEST . If open circuit is not found, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. After repair, repeat DTC CONFIRMATION TEST .
- Ensure ignition switch is in LOCK position. Disconnect VSS 3-pin harness connector C20, located in transmission extension case. See Figure . Turn ignition switch to ON position. Measure voltage between VSS harness connector C20 terminals No. 2 (Black/Yellow wire) and No. 3 (Blue/Black wire). See Fig 1 . If voltage is 10-14 volts, go to next step. If voltage is not 10-14 volts, repair open or short circuit in Black/Yellow wire between ground and VSS, or in Blue/Black wire between ECM and VSS. After repair, repeat DTC CONFIRMATION TEST .
- Ensure ignition switch is in ON position. Measure voltage between VSS harness connector C20 terminals No. 1 (Blue/Yellow wire) and No. 2 (Black/Yellow wire). If voltage is approximately 4 volts, go to next step. If voltage is not approximately 4 volts, go to step 6 .
- Turn ignition switch to LOCK position. Perform VSS visual inspection, also perform VSS component test. See VEHICLE SPEED SENSOR under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article. If VSS is faulty, replace VSS. If VSS is okay, check VSS connector for poor, loose, corroded or damaged connector terminals. If connector terminals are faulty, repair as necessary and DTC CONFIRMATION TEST . If connector terminals are okay, substitute VSS with a known good unit and repeat DTC CONFIRMATION TEST .
- Turn ignition switch to LOCK position. Disconnect combination meter 16-pin harness connector G11, located behind instrument cluster. See Figure . Turn ignition switch to ON position. Measure voltage between VSS harness connector C20 terminals No. 1 (Blue/Yellow wire) and No. 2 (Black/Yellow wire). See Fig 1 . If voltage is not approximately 4 volts, go to next step. If voltage is approximately 4 volts, replace VSS and repeat DTC CONFIRMATION TEST .
- Turn ignition switch to LOCK position. Disconnect cruise control module 12-pin harness connector E132, located in left rear of engine compartment. Turn ignition switch to ON position and measure voltage between VSS harness connector C20 terminals No. 1 (Blue/Yellow wire) and No. 2 (Black/Yellow wire). See Fig 1 . If voltage is approximately 4 volts, replace cruise control module and repeat DTC CONFIRMATION TEST . If voltage is not approximately 4 volts, substitute ECM with a known good unit and repeat DTC CONFIRMATION TEST .