Engine Management Light

zedwheels

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Help please.
When I bought the car the back box had been removed for some crackle and pop! But not liking this sound I've had the back box refitted, but, since then the engine management light is on. Put a code reader on it and it shows fault code.P0056 Heater control circuit bank 2 sensor 2

After resetting it thought that it was sorted but it's come back on :cry:
Does anyone know what part or part number it's referring to please??
 
Forgot to mention that while the exhaust was removed for welding the battery was disconnected for two hours.
 
Heater circuit on exhaust sensor post cat has failed and set the code. Remove it and replace with an OEM brand like Bosch don't go for cheap brands
 
colb said:
Heater circuit on exhaust sensor post cat has failed and set the code. Remove it and replace with an OEM brand like Bosch don't go for cheap brands

Hi Colb. Thanks for response It's my son in law that's going to fit it and he's confused as to which of the two sensors is the Post sensor, is there any thing to identify which is the heater sensor?? I have'nt been under there so couldn't help him :cry:
 
Follow the exhaust down from the cat you will see pre cat sensor sits in front of the cat after the cat you will find the post cat sensor sitting in the exhaust pipe same for both exhaust banks. Your code is telling you that the heater circuit in bank 2 post cat sensor has failed. Bank 2 will be the rearmost cat on the engine as you look into the engine bay follow the sensor wire up from the sensor to its connector on the side of the cam cover, disconnect it and feed the wire down to the underside of the car then using a sensor spanner slip it over the wire and onto the sensor to unscrew it. Be prepared for a fight they can be awful to undo.
https://www.realoem.com/bmw/enUS/showparts?id=BT32-EUR-12-2003-E85-BMW-Z4_25i&diagId=18_0497
Post cat bank2 is number 4 in diagram.
 
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