Diagnosis & Repair
- Check spark plugs and ignition system. See BASIC TESTING article. Repair as necessary. If ignition system is okay, ensure ignition is off.
- Access ECM harness connectors behind glove box. Connect Check Harness "A" (SST 09990-01000) to ECM. See TEST PREPARATION under SELF-DIAGNOSTIC SYSTEM. Turn ignition on. Measure voltage between ground and injector terminals at ECM "B" connector. See IDENTIFYING INJECTOR TERMINALS table. If voltage is 9-14 volts for each circuit, go to step 4). If voltage is not 9-14 volts, go to next step.IDENTIFYING INJECTOR TERMINALS
Injector No. (1) Terminal No. Wire Color 1 20 Yellow 2 19 Red 3 18 Black 4 17 Black/Red 5 16 Blue/White 6 15 Red/White 7 40 Blue/Red 8 39 Green (1) Terminals are located in ECM "B" connector. - Disconnect injector of misfiring cylinder. Using ohmmeter, measure resistance between injector terminals. With injector temperature at 68°F (20°C), if resistance is 13.4-14.2 ohms, check for open or short circuit in wiring harness between ECM and injector. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If resistance is not 13.4-14.2 ohms, replace injector.
- Check fuel pressure. See BASIC TESTING article. Repair as necessary. If fuel pressure is okay, check fuel injectors. See SYSTEM/COMPONENT TESTS article. Replace as necessary.
- If all injectors are okay, check EGR system. See SYSTEM/COMPONENT TESTS article. Repair as necessary. If EGR system is okay, check MAF sensor and ECT sensor. See SYSTEM/COMPONENT TESTS article. Replace as necessary. If both components are okay, check engine compression, valve clearance and valve timing. See BASIC TESTING article. Repair as necessary.