P0104 code meaning
Mass or Volume Air Flow Sensor A Circuit Intermittent
Powertrain system Generic code P01xx codes Check engine light
What P0104 means
The mass air flow sensor (MAF) sits between the air filter and the throttle or compressor and measures how much air the engine draws in; fuel quantity, load and ignition are calculated from it. Most are hot-film or hot-wire sensors that output either a voltage or, on GM, Saab and newer Ford systems, a frequency. P0104 covers brief dropouts or jumps in the signal without a permanent low or high fault – the classic sign of a loose contact. In Ford's 2020–2023 gasoline summary the code is set once more than 25 short open or short-circuit events have been counted. GM and Saab do not list P0104 in the documents checked; there such dropouts end up under P0102/P0103 or P0101. The trip count is not stated by Ford. Diagnosis means moving the harness while watching the live signal and checking terminals for corrosion and weak tension.
P0104 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P0104
- Check engine light on, may go out again
- Occasional hesitation, misfire-like stumble, flat spot
- Intermittent rough idle or stalling
Common causes of P0104
- Most likelyLoose contact at the sensor connector (corrosion, spread terminals, broken latch)
- PossibleChafed or partly broken wire moved by the engine
- PossibleSensor electronics dropping out (temperature-dependent)
- Less likelyPoor ground or electrical interference
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Mass air flow sensorMass air flow sensor wiringSensor supply voltage
What each part of P0104 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 04 | The exact fault in that area. |
What to do next
- Note P0104 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0104
What does P0104 mean?
P0104 means "Mass or Volume Air Flow Sensor A Circuit Intermittent". The mass air flow sensor (MAF) sits between the air filter and the throttle or compressor and measures how much air the engine draws in; fuel quantity, load and ignition are calculated from it. It is a generic code, so it means the same on every make.
Is it safe to drive with P0104?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0104 fail an emissions test?
Yes, it can. P0104 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0104 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0104 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.