P0104: Mass or Volume Air Flow Sensor A Circuit Intermittent. Meaning, possible symptoms and checks before repair.
Meaning, symptoms, causes and checks
The controller finds the MAF A input intermittently interrupted or erratic. A normal workshop reading does not exclude an intermittent fault. Outputs may use voltage, frequency or digital data, so test the installed sensor type.
Affected system: Powertrain
Symptoms
- Engine warning light; a fallback operating mode is possible.
- Uneven idle, hesitation or reduced power, depending on the control strategy.
Possible causes
- Loose terminals or vibration-damaged wiring.
- Intermittent MAF sensing-element or internal-electronics failure.
What to check
- Record RPM, load and MAF at the time of storage; determine whether the fault is current or intermittent.
- Inspect the connector, wiring route, MAF installation and intake-duct sealing without touching the sensitive element.
- Measure supply and ground using the diagram; do not assume every MAF uses the same supply voltage.
- Log signal and supplies while gently moving the harness; look for dropouts associated with vibration or temperature.
- After repair, clear codes and recheck the MAF input under the original recorded conditions, following the manufacturer’s procedure.
Also written as: P0104-00, P010400, PO104 (some scan tools add the fault-type byte, e.g. -00).