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1999 BMW 540IT E39
4.4L V8•RWD•AUTOMATIC•gas
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Repairs0Labor496Torque2399Fluid8DTC1210Battery1Maintenance0Recalls0
P0100moderate severityPowertrain

Mass Air Flow (MAF) Circuit

on 1999 BMW 540iT E39 4.4L V8 · RWD

What this code means

The PCM detected a general malfunction in the Mass Air Flow sensor circuit.

Symptoms

  • Check Engine Light
  • Poor acceleration
  • Rough idle
  • Engine stalling
  • Black smoke

Common causes

  • Faulty MAF sensor
  • Dirty MAF sensor element
  • Air leak after MAF
  • Wiring issue
  • Damaged air filter

Diagnostic steps

  1. Inspect MAF sensor for contamination
  2. Check for air leaks between MAF and throttle body
  3. Test MAF signal with scan tool
  4. Inspect wiring and connector
  5. Try cleaning MAF with approved cleaner

Repair notes

Clean MAF sensor with electronics cleaner. Replace if cleaning does not resolve.

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