P1139 Audi Code - Long Term Fuel Trim Add. Fuel B2 System Too Rich

P1139 indicates that the long-term fuel trim on Bank 2 is too rich, meaning the engine control unit (ECU) detects an excessive amount of fuel compared to air in the combustion process.

Common symptoms include poor fuel economy, rough idling, black smoke from the exhaust, difficulty starting the engine, and potentially an illuminated check engine light.

The code can be caused by a faulty fuel injector, a malfunctioning oxygen sensor, a vacuum leak, a dirty mass airflow sensor (MAF), or a problem with the fuel pressure regulator.

Yes, a faulty oxygen sensor on Bank 2 can send incorrect readings to the ECU, leading to improper fuel mixture adjustments and triggering the P1139 code.

Diagnosis typically involves checking for vacuum leaks, inspecting the oxygen sensors and fuel injectors, testing the mass airflow sensor, and verifying proper fuel pressure.

Driving with the P1139 code is not recommended, as it can lead to poor engine performance, damage to the catalytic converter, and increased emissions if left unresolved.

Repairs may include cleaning or replacing the mass airflow sensor, replacing faulty oxygen sensors, repairing vacuum leaks, or servicing the fuel injectors.

Yes, a dirty or malfunctioning mass airflow sensor can provide incorrect air intake readings, causing the ECU to add too much fuel and trigger the P1139 code.

Repair costs vary depending on the root cause but can range from $150 to $500 or more, depending on whether parts like oxygen sensors or injectors need replacement.

Clearing the code without addressing the underlying problem may temporarily turn off the check engine light, but the code is likely to return until the issue is properly resolved.