OBD-II Code · Sensors
P0102
MAF Circuit Low Input
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$10–$250
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Try MAF cleaner first
MAF sensor reading too low.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
- Stalling
- Hesitation
- Black smoke
Likely causes
- Dirty or failed MAFMost common
- Wiring issue
- Disconnected sensor
- Intake boot leak
Read the full diagnostic procedureP0102 means the MAF signal voltage or frequency is below the rationality floor — on an analog sensor that is typically under 0.2V key-on engine runni…
P0102 means the MAF signal voltage or frequency is below the rationality floor — on an analog sensor that is typically under 0.2V key-on engine running, on a digital Hitachi/Bosch HFM frequency MAF that is below roughly 1.0 kHz at idle. This is almost always a wiring or power-supply fault, not a dead sensor.
Cheapest-first ladder
- back-probe the 12V or 5V supply wire at the MAF connector key-on (most GM/Ford MAFs need a 12V switched supply through the underhood fuse box, most import MAFs run on 5V from the ECM) — no power means a blown fuse or a melted PCM-fed relay contact; verify ground integrity by measuring voltage drop from the MAF ground pin to battery negative with the engine running, must be under 0.1V; with power and ground confirmed, jumper the signal wire to 5V momentarily and see if the scan tool reads a high MAF value — if yes, the wiring is good and the sensor is dead; airflow at idle reading 0.0 g/s with the engine clearly running is the signature of P0102 and confirms either no signal or no power.
- Do not replace the MAF before checking the fuse and the underhood relay — a $5 fuse fixes more P0102s than a $250 sensor on Ford trucks specifically.
Vehicle-specific patterns2004-2010 Ford F-150/Expedition 5.4L set P0102 when the underhood PDB fuse for the MAF/coil bank corrodes from water intrusion through the cowl drain…
- 2004-2010Ford F-150/Expedition 5.4L set P0102 when the underhood PDB fuse for the MAF/coil bank corrodes from water intrusion through the cowl drain;
- 2007-2013GM Silverado/Sierra 5.3L set P0102 from a broken locking tab letting the MAF connector vibrate loose, intermittent before going hard-fault;
- 2005-2010Chrysler/Dodge Hemi 5.7L sees P0102 from a chafed signal wire at the airbox-to-throttle-body bridge;
- 2003-2009Toyota 4Runner/Tacoma 4.0L 1GR-FE sees P0102 from internal MAF failure where the sensor reads 0 g/s constantly and replacement is the only fix.
Estimated repair$5 to $350.
Look up another code
P0102 — frequently asked
What does a P0102 code mean?
MAF sensor reading too low.
What causes a P0102 code?
Common causes: Dirty or failed MAF; Wiring issue; Disconnected sensor; Intake boot leak.
What are the symptoms of a P0102 code?
Typical symptoms: Check engine light; Stalling; Hesitation; Black smoke.
Is it safe to drive with a P0102 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $10-$250 — try MAF cleaner first.
How do I diagnose a P0102 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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