Test F: Tachometer Inoperative
- Turn ignition switch to LOCK position. Remove instrument cluster, but leave harness connectors connected. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Start engine. Measure voltage by backprobing between ground and instrument cluster harness connector C226a terminal No. 11 (Light Green wire). Raise and support vehicle. Start engine and operate vehicle at indicated engine speeds. See TACHOMETER SIGNAL VOLTAGE table. If voltages are as specified, go to next step. If voltages are not as specified, go to step 4.TACHOMETER SIGNAL VOLTAGE
Engine Speed (RPM) Voltage 1000 1.69 1500 2.64 2000 3.44 2500 4.50 3000 5.22 - Turn ignition switch to LOCK position. Disconnect instrument cluster 12-pin harness connector C266a. Disconnect Powertrain Control Module (PCM) 104-pin harness connector C275. PCM is located behind glove box. Measure resistance between instrument cluster harness connector C266a terminal No. 11 (Light Green wire) and PCM harness connector C275 terminal No. 3 (Green/White wire). See Figure and Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Light Green wire and/or Green/White wire.
- Turn ignition switch to RUN position. Measure voltage between ground and instrument cluster harness connector C266a terminal No. 11 (Light Green wire). If voltage is 10 volts or more, repair short to voltage in Light Green wire and/or Green/White wire between instrument cluster and PCM.
- Disconnect all instrument cluster harness connectors. Inspect for corroded or pushed out pins. Connect all instrument cluster harness connectors. Operate system and verify if concern still exists. If concern still exists, replace instrument cluster. See REMOVAL & INSTALLATION . If concern does not exist, system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.
NOTE:
Wire color changes between instrument cluster and Powertrain Control Module (PCM) from Light Green to Green/White at splice behind top center of instrument panel.
NOTE:
Wire color changes between instrument cluster and Powertrain Control Module (PCM) from Light Green to Green/White at splice behind top center of instrument panel.