Test J: Powertrain Control Module Does Not Respond To NGS Tester
WARNING: This page is about a different car, the 2001 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
If test results indicate Powertrain Control Module (PCM) is faulty, always check for any engine performance related Diagnostic Trouble Codes (DTC) 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 switch to LOCK position. Disconnect Powertrain Control Module (PCM) harness connector. PCM is located in engine compartment on left side of firewall. Figure. Inspect PCM harness connector for loose, damaged or corroded terminals. Repair harness connector as necessary and retest system for normal operation. If harness connector is okay, reconnect harness connector. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). DLC is located below left side of instrument panel, to right of steering column. Turn ignition switch to RUN position and perform data link diagnostic test. See DATA LINK DIAGNOSTIC TEST under SELF-DIAGNOSTIC SYSTEM. If NGS tester indicates PCM: NO RESPONSE ON CKT 914 (BUS +), go to next step. If NGS tester indicates PCM: NO RESPONSE ON CKT 915 (BUS -), go to step 4.
- Turn ignition switch to LOCK position. Disconnect NGS tester. Disconnect PCM harness connector. Measure resistance in Tan/Orange wire between PCM harness connector terminal No. 16 and DLC terminal No. 2. See Figure and Fig 1 . If resistance is 5 ohms or more, go to next step. If resistance is 5 ohms or less, replace PCM. Retest system for normal operation.
- Disconnect 76-pin in-line harness connector C201. In-line harness connector C201 is located behind left side of instrument panel. See Figure. Inspect in-line harness connector for loose, damaged or corroded terminals. Repair harness connector as necessary and retest system for normal operation. If harness connector is okay, measure resistance in Tan/Orange wire between in-line harness connector C201 terminal No. 59 and DLC terminal No. 2. See Figure and Figure . If resistance is 5 ohms or less, repair open in Tan/Orange wire between PCM and in-line harness connector C201. If resistance is 5 ohms or more, repair open in Tan/Orange wire between in-line harness connector C201 and DLC. Restore harness connections and test system for normal operation.
- Turn ignition switch to LOCK position. Disconnect NGS tester. Disconnect PCM harness connector. Measure resistance in Pink/Light Blue wire between PCM harness connector terminal No. 15 and DLC terminal No. 10. See Figure and Fig 1 . If resistance is 5 ohms or more, go to next step. If resistance is 5 ohms or less, replace PCM. Retest system for normal operation.
- Disconnect 76-pin in-line harness connector C201. In-line harness connector C201 is located behind left side of instrument panel. See Figure. Inspect in-line harness connector for loose, damaged or corroded terminals. Repair harness connector as necessary and retest system for normal operation. If harness connector is okay, measure resistance in Pink/Light Blue wire between in-line harness connector C201 terminal No. 60 and DLC terminal No. 10. See Figure and Figure . If resistance is 5 ohms or less, repair open in Pink/Light Blue wire between PCM and in-line harness connector C201. If resistance is 5 ohms or more, repair open in Pink/Light Blue wire between in-line harness connector C201 and DLC. Restore harness connections and test system for normal operation.