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DTC codes / P01xx · Fuel and air metering / P0104

P0104Mass/Volume Air Flow Circuit Intermittent

P0104 indicates that the engine control module (ECM) has detected an intermittent fault in the mass air flow (MAF) or volume air flow sensor circuit. The ECM sees the sensor signal dropping out or jumping erratically rather than providing a steady, plausible reading, which can upset fuel delivery and engine operation.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Check engine light illuminated, often with no other noticeable symptoms
  • Intermittent engine stumble or hesitation during acceleration
  • Rough idle or stalling that comes and goes
  • Poor fuel economy or black smoke from the tailpipe
  • Delayed or harsh transmission shifts due to incorrect load signal

Common causes, most likely first

  1. Contaminated or failing mass air flow sensor element
  2. Damaged or loose wiring between the MAF sensor and the ECM
  3. Corroded or backed-out terminals at the MAF sensor connector
  4. Intake air leaks after the MAF sensor causing erratic readings
  5. Failed MAF sensor internal electronics
  6. Poor electrical ground for the MAF sensor circuit

How to diagnose and fix it

  1. Inspect the MAF sensor connector and wiring for looseness, corrosion, or chafing
  2. Check for intake air leaks between the MAF sensor and throttle body
  3. Clean the MAF sensor element with a dedicated MAF cleaner
  4. Backprobe the MAF signal wire and wiggle-test the harness while watching live data
  5. Compare MAF sensor readings to expected values under different engine speeds
  6. Replace the MAF sensor if cleaning and wiring checks do not resolve the intermittent signal

Intermittent MAF faults that fool technicians

  • A dirty MAF sensor often causes intermittent dropouts before it fails completely, so cleaning can restore a steady signal without replacement.
  • Wiring harness chafing near the air box or engine mount is a common hidden cause that only shows up when the engine moves under load.
  • Some vehicles set P0104 when the MAF sensor signal is momentarily lost during cranking, which can be a normal artifact if the code does not return.
  • An intake air leak after the MAF sensor can create erratic readings that mimic a failing sensor, so always pressure-test the intake tract first.

Can I keep driving with P0104?

You can usually drive with P0104, but avoid heavy acceleration and towing until the fault is repaired because intermittent MAF signals can cause stalling or poor fuel control. If the engine stumbles or stalls frequently, park the vehicle and diagnose it promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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