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2012 MERCEDES-BENZ ML
3.5L V6•AWD•AUTOMATIC•gas•M272
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Repairs0Labor492Torque2165Fluid8DTC1852Battery2Maintenance0Recalls0
P1146moderate severityPowertrain

Mass Air Flow Sensor Malfunction

on 2012 Mercedes-Benz ML 3.5L V6 · AWD

What this code means

The ECU detected that the MAF sensor signal is erratic or outside the expected range for current engine operating conditions. The MAF sensor is critical for accurate fuel metering on Mercedes-Benz engines.

Symptoms

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

Common causes

  • Dirty or contaminated MAF sensor element
  • Air leak in intake tract after MAF
  • Faulty MAF sensor
  • Damaged wiring or connector
  • Intake boot torn

Diagnostic steps

  1. Clean MAF sensor with approved MAF cleaner
  2. Inspect intake boot and clamps for air leaks
  3. Monitor MAF readings vs specifications
  4. Test sensor wiring and connector
  5. Compare readings at idle and 2500 RPM

Repair notes

Clean the MAF sensor first; replace if readings remain out of specification.

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