P2181

P2181

Diagnosis information - DME (DFI)

Thermostat stuck open

NOTE: The diagnostic conditions can best be established on a (roller-type) dynamometer.

Diagnostic conditions
- Coolant temperature when engine starts -7 °C ... +50 °C (19 °F ... 122 °F)
- Ambient temperature -10 °C ... +40 °C (14 °F ... 104 °F)
- Drive for more than 10 minutes:
- Vehicle speed max. 100 km/h (62 mph)
- Average vehicle speed 30 km/h ... 100 km/h (19 mph ... 62 mph)
- Average mass air flow 80 kg/h ... 135 kg/h (depending on average speed)
- Overrun phases less than 100 s in total

Possible fault causes
- for PDK transmission:
- Coolant shutoff valve stuck open (e.g. vacuum hose not connected)

- Influence by engine-block heater
- Seal in thermostat housing faulty
- Thermostat housing faulty
- Thermostat faulty