Test N: Tachometer Reads Too High, Too Low Or Erratic

Turn ignition off. Remove instrument cluster. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Leave connectors connected. Set voltmeter on AC scale. Start engine and allow to idle. Connect voltmeter between ground and instrument cluster connector C272 terminal No. 4 (Green/White wire). See Figure . Increase engine speed while observing voltmeter. See TACHOMETER VOLTAGE  table. If voltage readings are as specified, replace instrument cluster. See the INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. If voltage readings are not as specified, problem is in Powertrain Control Module (PCM). See appropriate TESTS W/CODES article in the ENGINE PERFORMANCE section.