P1189 BMW Possible Causes
- Intake air leaks
- Faulty front heated oxygen sensor
- Misfire
- Faulty fuel injectors
- Exhaust gas leaks
- Poor fuel pressure
- Fuel shortage
- Faulty mass air flow (MAF) sensor
- Poor positive crankcase ventilation (PCV) hose connection
How to Fix BMW P1189 Code?
Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
When is the Code Detected?
– The fuel injection system is not working properly.
– The mixture ratio compensation amount is not correct
Possible Symptoms
- Engine light on (or engine service warning light soon)
- Excessive fuel consumption
P1189 BMW Meaning
With the air/fuel mixture ratio self-learning control, the actual mixture ratio can be brought closer to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The engine control module (ECM) calculates the necessary compensation to correct the deviation between the actual and theoretical ratios.
In cases where the compensation value amount is extremely high (the actual mixture ratio is too lean), the ECM judges the condition as a fuel injection system malfunction and illuminates the MIL (detection logic trigger 2).