Vehicle speed signal
For vehicles without tachograph: Check the circuit between the vehicle speed sensor on the propeller shaft and the coordinator. Check the vehicle speed sensor on the propeller shaft. For vehicles with a tachograph: Check the circuit between the tachograph and coordinator. Check the tachograph supply voltage circuit. Check whether the tachograph has generated any fault codes.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
The vehicle speed signal from the vehicle speed sensor or tachograph has been implausibly high. On vehicles without a tachograph, the coordinator receives the vehicle speed signal from the vehicle speed sensor. On vehicles with a tachograph, the coordinator receives the vehicle speed signal from the tachograph.
For vehicles without a tachograph, the fault may be due to: Faulty vehicle speed sensor on the propeller shaft. Short circuit in the vehicle speed sensor circuit. For vehicles with a tachograph, the fault may be due to: Short circuit in the circuit between the tachograph and coordinator. Internal fault in the tachograph.