VW Golf V - Poor engine starting performance | HELLA

If the fault pattern listed above is reported, the cause may be a defective coolant temperature sensor. In addition, error codes (triggered by implausible sensor values) may be stored in the engine control unit.

Error code 'equivalent' to:

- P1556, 'Charge pressure control negative'.

In addition, with the potentially misleading turbocharger pressure error code (P1556), excessive engine knocking while idling could be indicative of a faulty sensor.

In this case, proceed as follows:

- Disconnect wire harness multi-plug from the engine control unit and the coolant temperature sensor and perform a continuity test.

- Check the contacts on both sides for corrosion and mechanical damage and repair them if necessary.

- Check the ground connections.

- Check that coolant temperature sensor is functioning properly. As guidelines, the specified resistance value should be _ 2080 Ω at 25°C and _ 289 Ω at 85°C respectively.

Replace the sensor if necessary (see Figure 1.).

Hella coolant temperature sensor: 6PT009309-331

Then clear the entries present in the error memory.