good morning everyone, a bmw 118d year 2007 2000cc 105 kw n47d20a came into the workshop with engine light on and the car does not render.

made diagnosis found these error codes :

41BB EXHAUST GAS BACK PRESSURE SENSOR

4A6E GLOW PLUG CYLINDER 1

3EE0 LIQUID TEMPERATURE SENSOR

checked the parameters it gave me water temperature -40 we replaced the water temperature sensor which is plastic mounted on the cylinder head in front, replaced the exhaust gas pressure sensor cleared the errors the car runs well.

We noticed that the water temperature sensor was still stored in the memory as an error, we checked the wiring harness and found signs of oxide on the plugs as if water had entered, I checked the wiring harness up to the engine control unit, unplugged the plug and found oxide inside the control unit, most likely, as had happened to me on a Peugeot 207, due to capillarity, the coolant passing through the water temperature bulb went up to the control unit.

Now the car is running and the error code has not reoccurred.

good work to all

Claudio Terreni Tito