Possible causes

– Faulty Fuel Temperature Sensor
– Fuel Temperature Sensor harness is open or shorted
– Fuel Temperature Sensor circuit poor electrical connection

Tech notes

Replaced Fuel Temperature Sensor

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0188 VOLKSWAGEN Description

The fuel tank temperature sensor is used to detect the fuel temperature inside the fuel tank. The sensor modifies a voltage signal from the Engine Control Module (ECM). The modified signal returns to the ECM as the fuel temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.