Tachometer Test
- Disconnect negative battery cable. Disable air bag system. See AIR BAG RESTRAINT SYSTEM
article in the ACCESSORIES/SAFETY EQUIPMENT section. Remove instrument cluster, leaving connectors attached. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Reconnect battery cables.
- Connect external tachometer. Start engine. Backprobe terminal 6B (Green/White wire) of Black 12-pin connector with DVOM while operating engine at speeds specified in TACHOMETER INPUTS table. If voltages are as specified, go to next step. If voltages are not as specified, see TESTS W/CODES
article in ENGINE PERFORMANCE section.
TACHOMETER INPUTS
| Engine RPM |
Voltage |
| 1000 |
1.69 |
| 1500 |
2.64 |
| 2000 |
3.44 |
| 2500 |
4.50 |
| 3000 |
5.22 |
- Turn ignition off. Remove instrument cluster. Measure resistance between tachometer terminal "B" and cluster connector terminal 2B. Measure resistance between tachometer terminal "G" and cluster connector terminal 5B. Measure resistance between tachometer terminal "S" and cluster connector terminal 6B. If resistance is less than 5 ohms for each measurement, replace tachometer. If resistance is not less than 5 ohms for any measurement, replace printed circuit board.