Test B: Powertrain Control Module Does Not Respond To Scan Tool
NOTE:
If test results indicate PCM is faulty, always check for engine performance-related DTCs prior to replacing PCM. If any DTCs are present, service DTCs as necessary and retest. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
- Turn ignition off. Remove NGS tester. Disconnect PCM. Connector is located behind glove box. Inspect connector for loose, damaged or corroded terminals. Repair connector as necessary and retest system for normal operation. If connector is okay, measure resistance of Yellow/Red wire between terminal No. 74 at PCM connector and terminal No. 1 at Data Link Connector (DLC) C252. See Figure and Fig 1 . If resistance is less than 5 ohms, go to step 3. If resistance is 5 ohms or more, go to next step.
- Measure resistance of Yellow/Red wire between female side of in-line connector C272 terminal No. 2 and DLC C252 terminal No. 1. In-line connector C272 is located behind center top of dash. See Fig 2. If resistance is less than 5 ohms, repair open in Yellow/Red wire between PCM connector and in-line connector C272. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Red wire between in-line connector C272 and DLC C252. Retest system.
- Measure resistance of Yellow/Black wire between terminal No. 75 at PCM connector and terminal No. 2 at DLC C252. If resistance is less than 5 ohms, diagnose engine control system. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE and perform PCM system test. If resistance is 5 ohms or more, go to next step.
- Measure resistance of Yellow/Black wire between female side of in-line connector C272 terminal No. 5 and DLC C252 terminal No. 2. In-line connector C272 is located behind center top of dash. See Fig 2. If resistance is less than 5 ohms, repair open in Yellow/Black wire between PCM connector and in-line connector C272. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Black wire between in-line connector C272 and DLC C252. Retest system.