Diagnostic Aids

An open or short in injector circuit will set DTC. The open or short will also cause a misfire and inoperative injector. A misfire DTC will be set indicating which cylinder is malfunctioning. Excessively high or low long and short term fuel trim indicate the possibility of a bad injector. See INJECTOR COIL TEST in SYSTEM & COMPONENT TESTING article to check injector.

1. Perform On-Board (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine does not start, see BASIC DIAGNOSTIC PROCEDURES article.
3. Using scan tool, clear DTCs. Start and run engine for one minute and observe scan tool display. If any DTC from P0201 to P0206 resets, go to step  5. If no DTC resets, go to next step.
4. With ignition on and engine off, use scan tool to read FREEZE FRAME DATA and note parameters. Start engine and operate vehicle within FAILURE RECORDS conditions. If any DTC from P0201 to P0206 resets, go to next step. If no DTC resets, check for an intermittent problem. See DIAGNOSTIC AIDS .
5. Turn engine off. Disconnect appropriate injector harness connector related to DTC. Connect an injector tester (noid-light) to injector harness connector. Disable secondary ignition system to prevent engine from starting and crank engine. If noid-light blinks, see INJECTOR COIL TEST in SYSTEM & COMPONENT TESTING article. If noid-light does not blink, go to next step.
6. If noid-light was on steady in previous step, go to next step. If noid-light did not come on in previous step, go to step  8.
7. Disconnect PCM connector containing affected injector circuit. Connect test light between battery positive terminal and affected injector driver circuit at harness connector. If test light comes on, repair short to ground in injector driver circuit. If test light does not come on, replace PCM. Retest system.
8. Disconnect injector harness connector. Using an ohmmeter connected to Red/Blue wire of injector harness connector, probe wire for affected cylinder. If continuity is present, go to next step. If continuity is not present, repair open in injector harness wire. Retest system.
9. At PCM side of injector harness connector, check for short to voltage in affected cylinder wire. If short to voltage exists, repair short in affected cylinder wire. Retest system. If short to voltage does not exist, go to next step.
10. Check for open circuit in affected cylinder wire between PCM and injector harness connector. Repair as necessary. If wires are okay, replace PCM. Retest system.