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Top Tip - VAG

Engine warning lights due to temperature gauge fluctuations

Covers -  1.8 and 2.0 TFSI (Generation 3)


The vehicle's engine warning light is displayed, due to possible issues with temperature gauge fluctuating between 60 and 110°C and/or, the heater not getting hot enough.

Possible faults in the engine:

  • P2181 - Fault in cooling system
  • P00B7 - Engine cooling not adequate
  • P0116 - Coolant temp sensor 62 implausible signal
  • P0652 - Sensor reference voltage 'B' circuit low


  • Electronic thermostat fault or leaking of coolant into the sensor.

  • The electronic thermostat fails, which can sometimes lead to a coolant leak through the electrical connector.


  1. Remove the electrical connector of the thermostat and inspect.
  2. If coolant is found, replace the electronic thermostat and repair wiring carefully if required. (The electronic thermostat is on the back of the water pump which is under the inlet manifold).