2AF3
Moderate2AF3 — Mass Air Flow Sensor Signal Implausible
Description
What the Code Means
2AF3 is a BMW-specific code that flags an implausible signal from the mass air flow (MAF) sensor. It's similar to 2AF2 and has the same causes: a contaminated sensing element, an intake leak, or normal sensor aging.
The DME compares MAF readings against other engine operating parameters. When the signal doesn't match the calculated value, the control unit falls back to alternative fuel mixture strategies. The engine keeps running, but drivability suffers.
Symptoms
Symptoms
- Rough idle;
- Hesitation when you press the accelerator;
- Reduced power;
- Check Engine light on.
Causes and fixes
Diagnosis and Repair
- Run diagnostics with ISTA and read the MAF sensor parameters.
- Inspect the intake system for leaks (unmetered air).
- Clean the MAF sensor; replace it if heavily contaminated or aged. BMW OEM sensor part number:
13627550076. - Clear the fault codes and take it for a test drive to verify the fix.
Possible secondary damage
Secondary Issues
- Prolonged driving with this fault can damage the catalytic converter;
- Increased emissions from incorrect mixture.