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BMW and MINI Fault Codes – P0313, P0171, P0172 Misfire with Low Fuel, etc.

March 1, 2011

This answer is applicable for many BMWs in addition to the one listed below.

Q
car year: 2002 car model: 330i My car seems to run well but my check engine light has come on. When I check the OBD-II codes I get these three: P0313 Misfire detected with low fuel P0171 System to lean bank 2, P0172 System to lean bank 1. I did not find a matching response to another question that matched my model and was hoping that you could provide guidance on what to replace or repair. Thanks for your help.

A
The codes that you have mentioned may have various core possibilities, but we would consider a weak fuel pump as a likely fault. We have seen these codes prior to fuel pump failures, on various later model BMWs. Have you cleared the codes and have they come back? If the codes were cleared and did not return, we would chalk it up to a low fuel condition. However, if the codes do return, then we would recommend testing the operating fuel flow and pressure (using a fuel pressure gauge). If a flow test and/or the operating pressure are below specifications (as in the Bentley repair manual), the pump should be replaced.

Bentley repair manual:
BMW

OBD-II Fault code reader:
BMW

Fuel pumps:
BMW

Fuel pressure test gauge:
BMW

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