Tachometer Inaccurate or Inoperative

TACHOMETER INACCURATE OR INOPERATIVE

DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The instrument panel cluster (IPC) displays the engine speed based on the information from the engine control module (ECM) or the powertrain control module (PCM). The ECM/PCM converts the data from the engine speed sensor to a 2 pulses/engine revolution signal. The IPC receives a serial data message from the ECM/PCM indicating the engine speed.

REFERENCE INFORMATION

Schematic Reference
Instrument Cluster Schematics

Connector End View Reference
Instrument Panel, Gages, and Console Connector End Views

Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs

Scan Tool Reference
Scan Tool Data List

CIRCUIT/SYSTEM TESTING
1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With the scan tool, under Special Functions, perform the tachometer gage sweep test.
- If the tachometer gage does not sweep from its low to high position, replace the instrument panel cluster.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for IPC replacement, setup, and programming.