Engine RPM, Output Signal

ENGINE RPM, OUTPUT SIGNAL TO MAIN INSTRUMENT DISPLAY PANEL AND TCS CONTROL MODULE

Fault Symptoms
TCS OFF lamp on.
Tachometer (rev counter) does not work.

Diagnostic Procedure.
1. Connect a Scan Tool.
Check whether any diagnostic trouble codes have been generated in the Traction Control System (TCS). Trouble code B1710 will be stored in the event of no engine rpm and the TCS OFF indicator lamp should be on.
Deal with trouble code B1710 first, continue in the Traction Control System.

If diagnostic trouble code B1710 has not been generated and the tachometer does not work, continue in the Electrical System.

2. Connect a BOB to the TCS system. Do NOT connect the TCS control module.
Start the engine and check the output signal from pin 43 of the Motronic control module.
Measure the voltage across pins 6 and 13:
- idling speed _____ about 37 Hz
6.5 V
- 2500 rpm _____ about 125 Hz
6.5 V

If the signal is not OK, continue at "Procedure Before ECM Replacement". Component Tests
If the signal is OK, continue with step 3.

3. Clear the trouble code, drive the car on test and check whether the trouble code or fault symptoms persist.

If the trouble code is generated again, continue fault diagnosis in the Traction Control System.
If the trouble code is not generated again or the fault symptoms do not recur, the remedial measure taken was correct. Otherwise the fault is of intermittent type.