Tachometer Inaccurate or Inoperative

Tachometer Inaccurate or Inoperative

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit Description

The instrument panel cluster (IPC) receives the engine speed information from the engine control module (ECM)/powertrain control module (PCM) through the engine speed signal circuit. The ECM/PCM converts the data from the engine speed sensor to a (2 pulses)/(engine revolution) signal. The ECM/PCM also sends a class 2 message to the IPC indicating the engine speed.

Circuit/System Testing

1. Ignition ON, engine ON, verify the scan tool engine speed parameter for the IPC matches the tachometer display.

• If the engine speed parameter does not match the tachometer display, test the signal circuit for a high resistance.

2. If the circuit tests normal, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

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