BMW DTC P1191 – Pre Catalyst Fuel Trim System (Bank 2)
DTC P1191 meaning on BMW
The DTC P1191 on a BMW indicates an issue with the Pre Catalyst Fuel Trim System in Bank 2. This fault code is related to the fuel mixture being too lean in the pre-catalytic converter area of the exhaust system on the specified bank.
BMW DTC P1191 symptoms
Symptoms of a DTC P1191 on a BMW may include:
- Check Engine Light (MIL) illuminated
- Decreased engine performance
- Increased fuel consumption
- Rough idling or stalling
BMW DTC P1191 causes
Common causes of a DTC P1191 on a BMW include:
- Vacuum leaks
- Faulty oxygen sensor
- Fuel pressure regulator issues
- Dirty or clogged fuel injectors
- Exhaust system leaks
BMW DTC P1191 seriousness
The DTC P1191 should not be ignored as it can lead to poor engine performance, reduced fuel efficiency, and potential damage to the catalytic converter. It is recommended to address this issue promptly to prevent further complications.
How to diagnose DTC P1191 on BMW
To diagnose a DTC P1191 on a BMW, a mechanic may perform the following steps:
- Use a diagnostic scanner to retrieve the fault code and freeze frame data
- Inspect for any visible signs of exhaust leaks or damaged components
- Check the oxygen sensor readings and fuel trims
- Perform a smoke test to identify vacuum leaks
- Test the fuel pressure and injector operation
How to fix DTC P1191 on BMW
Depending on the root cause, fixing a DTC P1191 on a BMW may involve:
- Repairing any vacuum leaks and replacing damaged hoses
- Replacing a faulty oxygen sensor
- Addressing fuel pressure regulator issues
- Cleaning or replacing clogged fuel injectors
- Repairing exhaust system leaks
How to erase DTC P1191 on BMW
After fixing the underlying issue causing the DTC P1191, the fault code can be erased using a diagnostic scanner. This will clear the code from the vehicle’s memory and turn off the Check Engine Light. It is important to ensure that the repair has been successful before clearing the code.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
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