Voltage supply
â–¶ How to fix
Check the circuits for shorts and breaks. If the fault is found in the tachograph or impulse sensor, the relevant unit must be renewed.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
Detection
The voltage supply to the impulse sensor has been too high. The voltage should be between 6.5 - 9 V.
Possible cause
Short circuit in the cable between the tachograph and the impulse sensor or in the power supply cable to the tachograph. There may also be an internal fault in the tachograph or impulse sensor.