Pinpoint Test N - Tachometer Reads Too High, Too Low Or Erratic

Turn ignition off. Remove instrument cluster. See REMOVAL & INSTALLATION . Leave connectors connected. Set voltmeter on AC scale. Start engine and allow to idle. Connect voltmeter between ground and instrument cluster connector C3, pin No. 4 (Green/White wire). Increase engine speed while observing voltmeter. Voltmeter AC readings should be as follows:

At 1000 RPM, voltmeter should read 1.69 volts
At 1500 RPM, voltmeter should read 2.64 volts
At 2000 RPM, voltmeter should read 3.44 volts
At 2500 RPM, voltmeter should read 4.50 volts
At 3000 RPM, voltmeter should read 5.22 volts

If voltage readings are as specified, replace instrument cluster. If voltage readings are not as specified, replace Powertrain Control Module (PCM).