Engine Speed (Cars Without ETS)

FAULT DIAGNOSIS, ENGINE SPEED (cars without ETS)
Output Signal To Tachometer

Fault Symptom.
The tachometer does not work.

DIAGNOSTIC PROCEDURE

1. Checking The Wiring Harness
Check The Wiring harness between pin 58 of the Trionic control module and pin 2 of the tachometer for continuity.
Check The Wiring for continuity and shorting.

If the wiring is OK, continue with point 2.

If the wiring is not OK, rectify the fault.

2. Checking The Voltage Level
Connect the Trionic control module.
Remove the tachometer.
Start the engine and run it at idling speed.
Take a voltage reading across pins 2 and 6 of the tachometer.
At idling speed, about 850 rpm, a reading of about 0.5 V /28 Hz should be obtained.

If the reading is OK, check wiring.

If the reading is not OK, refer to Before Replacing A Control Module.