Radiator Fans Activation

P194600

Diagnosis information DME control unit

Radiator fans Activation

DANGER
High voltage.
Death or severe injuries due to high voltage or high current.

- De-energise the vehicle in accordance with the guidelines.
- Work must not be performed on parts carrying a high voltage.

Diagnostic conditions
The control unit must be active in order to test internal function sequences and diagnosable inputs/outputs.
In the event of a fault, check whether the fault is permanently >present<. To perform the check, erase the fault memory, meet the diagnostic conditions and read out the fault memory again.
- Ignition on

Possible fault causes
- Short circuit to B+/ground/between lines or open circuit in the lines

Fault setting condition(s)
- PWM signal to Radiator fan control module Short circuit Voltage Battery
- PWM signal to Radiator fan control module Open circuit

NOTE:
Diagnosis/Fault finding.
- Check of electrical wiring and connectors
- Current measurement shows a square-wave signal in OK case
- Voltage measurement of control line displays approximately the battery voltage
- Supply voltage U ~ 12 V