P1091 – BMW

Code : P1091
Make : BMW
Description : P1091 BMW Pre-Catalyst Fuel Trim Too Rich Bank 1
Possible causes :
– Low fuel pressure
– Large vacuum leak on engine
– Faulty Mass Air Flow (MAF) sensor
– Faulty Ignition
– Faulty fuel injector
Solutions :
– Carry out a Reset via CarDiag
– Choose a better quality fuel
– Check that the tank cap is securely closed
– Check the oil level and add more if it is lower than MAX
– Restart an Automatic diagnostic via CarDiag
– If the fault persists, you can check the “Possible causes” listed above : visually inspect (by yourself (tutorials to come) or by a professional) the wiring harness and the associated connectors, check for damaged components, and look for broken, bent, pushed, or corroded connector pins.

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