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, see and perform A-4: ENGINE SYSTEM CHECK under SYSTEM TESTS and go to next step.
- Turn ignition switch to LOCK position. Locate ECM 26-pin harness connector C51-3 under instrument panel, behind glove box. Disconnect and check ECM and harness connector C51-3 for poor, loose, corroded or damaged connector terminals. If connector terminals are faulty, repair as necessary and repeat DTC CONFIRMATION TEST . If connector terminals are okay, reconnect ECM harness connector. Start engine and allow it to idle. Backprobe and measure voltage between ground and ECM harness connector C51-3 terminal No. 3 (Black wire). See Fig 1 . If voltage is not 0.9-3.98 volts, go to next step. If voltage is 0.9-3.98 volts, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO-CODES article. After repair, repeat DTC CONFIRMATION TEST .
- Turn ignition switch to LOCK position. Disconnect Knock sensor single pin harness connector C70, located on center of cylinder block. Turn ignition switch to ON position. Measure voltage between ground and Knock sensor single wire harness connector C70 (Black wire). See Fig 1 . If voltage is 4-5 volts, replace faulty Knock sensor. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION article. After repair, repeat DTC CONFIRMATION TEST . If voltage is not 4-5 volts, check for open or short circuit in Black wire between ECM and Knock sensor. If short is found, repair as necessary and repeat DTC CONFIRMATION TEST . If open or short circuit is not found, substitute ECM with a known good unit and repeat DTC CONFIRMATION TEST .