Overheating
Check the water circulation. Check the check valve in the coolant circuit. Check water hoses and connections. Check that there is no air in the cooling system. Check the thermostat. Check the water valve. Check the fuel supply. Check the water pump. Measuring points 3 and 6 in the connector for the auxiliary heater control unit. Resistance value: 4 Ohms Check the overheat sensor. Measuring points 11 and 17 in the connector for the auxiliary heater control unit Resistance value: 150 kohm at -25 °C10 kOhm at +25 °C Check the water temperature sensor. Measuring points 14 and 18 in the connector for the auxiliary heater control unit. Resistance value: 650 kOhm at -25 °C 1000 kOhm at +25 °C Check the dosage pump. Measuring points 1 and 2 on dosage pump V41. Resistance: 20 Ohms
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
The difference in temperature between the water temperature sensor and overheat sensor is more than 70°C.
Poor water circulation or fault on overheat sensor or water temperature sensor.