Tachometer Not Operating Properly

Possible Causes:

• Attempt To Communicate With The PCM
• Engine Trouble Codes
• Instrument Cluster Self Test
• Observe The RPM Display In The Instrument Cluster
• Observe The RPM Display In The PCM
• Powertrain Control Module

Testing

1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, attempt to communicate with Powertrain Control Module (PCM). If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, perform NO RESPONSE FROM PCM (PCI BUS)  test under COMMUNICATION SYSTEMS.
2. Turn ignition off. To start gauges self-test, press and hold trip button on instrument cluster while turning ignition switch forward one position from LOCK to OFF position, then release trip button. If tachometer sweeps from zero RPM to 6000 RPM then back to zero RPM, go to next step. If tachometer does not sweep from zero RPM to 6000 RPM then back to zero RPM, replace instrument cluster. See ANALOG INSTRUMENT PANELS - CONCORDE, INTREPID & 300M article.
3. Using scan tool, retrieve PCM DTCs. If no PCM DTCs exist, go to next step. If any PCM DTCs exist, see SELF-DIAGNOSTICS - CONCORDE, INTREPID & 300M article in ENGINE PERFORMANCE.
4. Start engine. Using scan tool, select ENGINE, then sensors. Read ENGINE RPM. If scan tool displays more than 400 RPM, leave engine running and go to next step. If scan tool displays 400 RPM or less, replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION.
5. Using scan tool, select BODY, ELECTRO/MECH CLUSTER. Read ENGINE RPM. If scan tool displays more than 400 RPM, replace instrument cluster. See ANALOG INSTRUMENT PANELS - CONCORDE, INTREPID & 300M article. If scan tool displays 400 RPM or less, replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION.