LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2001 >> Malibu Base >> Repair and Diagnosis >> Electrical >> Gauges >> Analog Instrument Panels >> System Tests >> Test E: Tachometer Inaccurate

Test E: Tachometer Inaccurate

  1. If instrument cluster diagnostic system check has been performed, go to next step. If instrument cluster diagnostic system check has not been performed, perform instrument cluster diagnostic system check. See INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn ignition switch to LOCK position. Connect scan tool to Data Link Connector (DLC). DLC is located under instrument panel right of steering wheel. Turn ignition switch to RUN position. Using scan tool, observe ENGINE SPEED parameter in Powertrain Control Module (PCM) ENGINE DATA 1 data list. If ENGINE SPEED parameter does not match tachometer display, go to next step. If ENGINE SPEED parameter matches tachometer display, diagnose intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - CARS article in ENGINE PERFORMANCE.
  3. Turn ignition switch to LOCK position. Disconnect Powertrain Control Module (PCM) 80-pin harness connector C2. PCM is located under instrument panel, near steering wheel. Turn ignition switch to RUN position. Measure voltage between ground and PCM harness connector terminal No. 8 (White wire). See Figure . If battery voltage does not exist, go to next step. If battery voltage exists, go to step  5 .
  4. Disconnect instrument cluster 24-pin harness connector. Measure resistance between ground and instrument cluster harness connector terminal A7 (White wire). Resistance should be 2 ohms or more. Measure resistance in White wire between PCM harness connector C2 terminal No. 8 and instrument cluster harness connector terminal A7. See Figure and Figure . Resistance should be less than 2 ohms. If resistance is as specified, go to step  6 . If resistance is not as specified, repair short to ground, open or high resistance in White wire between instrument cluster and PCM. After repair, go to step  10
  5. Disconnect instrument cluster 24-pin harness connector. Measure voltage between ground and PCM harness connector terminal No. 8 (White wire). If battery voltage does not exist, go to step  7 . If battery voltage exists, repair short to voltage in White wire between PCM and instrument cluster. After repair, go to step  10 .
  6. Check instrument cluster harness connector for poor connections or loose terminals. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - CARS article in ENGINE PERFORMANCE. If problem still exists, go to step  8 . If problem does not exist, go to step  10 .
  7. Check PCM harness connectors for poor connections or loose terminals. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - CARS article in ENGINE PERFORMANCE. If problem still exists, go to step  9 . If problem does not exist, go to step  10 .
  8. Replace instrument cluster. After repair, go to step  10 .
    9. NOTE: New PCM needs to be programmed. See appropriate COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.
  9. Replace PCM. After repair, go to next step.
  10. Reconnect all disconnected components and connectors. Operate vehicle to verify repair. If problem does not exist, system is okay. If problem still exists, go to step  2 .
scientia non olet · About LEMON Manuals