16554moderate severityPowertrain
Fuel Trim Bank 1 Malfunction
on 2009 Audi A3 2.0L TDI · FWD
What this code means
The ECU cannot keep the air/fuel mixture within correct limits on bank 1 (equivalent to OBD P0170). Fuel trims are maxed out trying to correct a rich or lean condition.
Symptoms
- Check engine light on
- Poor fuel economy
- Hesitation or rough running
Common causes
- Vacuum or intake air leak
- Faulty mass air flow sensor
- Fuel pressure problem
- Faulty O2 sensor
Diagnostic steps
- Read live fuel trim values
- Check for intake and vacuum leaks
- Test MAF sensor and fuel pressure
- Inspect O2 sensor operation
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16515
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