P0102 code: Mass Air Flow (MAF) Circuit Low Input
P0102 means mass Air Flow (MAF) Circuit Low Input. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0102 means
The mass-airflow (MAF) sensor measures incoming air so the computer can match fuel to it. P0102 means the MAF's signal is reading too LOW — it's reporting less air than the engine is actually drawing. The most common cause is a dirty sensing element (it cleans up with MAF spray), an air leak between the MAF and the engine that lets in unmeasured air, or a wiring/connector fault. Because the computer trusts a too-low reading, it under-fuels, which causes hesitation and a lean-running engine.
P0102 symptoms
- Hesitation or stumbling under acceleration
- Rough or low idle, sometimes stalling
- Reduced power
- Possibly a lean code (P0171/P0174) alongside it
- Check-engine light
What it costs to fix P0102
Typical range: $20–$450 · about ~0.2–1 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| MAF sensor (clean) | $8–$15 | ~0.2–0.5 hrs |
| MAF sensor (replace) | $80–$350 | ~0.2–0.5 hrs |
| Intake duct / clamp repair | $10–$120 | ~0.3–1 hrs |
Clean first — a few dollars of MAF cleaner often fixes it. A replacement sensor is the main cost, and OEM units on some makes run higher than aftermarket. An intake-leak fix is usually cheap.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0102 for my exact vehicle →
How to fix P0102
Easy — basic tools, most owners can do this
- Inspect the MAF connector and wiring
Unplug the MAF connector and check for bent or corroded pins, green crust, or wiggle-loose terminals, then look along the harness for chafed or rodent-chewed wires. A low-reading circuit fault is often literally a bad connection, and this check costs nothing.
- Clean the MAF sensing element
Remove the sensor and clean it with MAF-specific spray — a film of oil or dust on the hot-wire element makes it report less air than is really flowing. Reinstall once dry and see if the reading comes up.
- Check for air leaks downstream of the MAF
Examine the intake tube between the MAF and the throttle body for cracks, loose clamps, or a popped-off hose. Air sneaking in after the sensor means the MAF genuinely sees less flow than the engine gets, dragging its signal low.
- Verify power and ground at the sensor
With the key on, use a multimeter to confirm the MAF connector has battery voltage (or the specified reference voltage) and a good ground per your vehicle's wiring diagram. Missing supply voltage means a wiring or fuse problem, not a bad sensor.
- Replace the MAF sensor
If the wiring checks out and cleaning didn't restore a normal signal, the sensor's element has failed low — replace it. Clear the code and confirm the grams-per-second reading responds crisply to throttle.
DIY or shop? Everything through cleaning and duct inspection is entry-level DIY, and even the multimeter checks are manageable with a wiring diagram and a little patience. Hand it to a shop if the voltage checks confuse you or the code returns after a quality replacement sensor — chasing an intermittent wiring fault through a harness is tedious work that benefits from professional test equipment.
Tools for the DIY steps: MAF sensor cleaner · Multimeter · Screwdriver or Torx bit set · OBD2 scanner · Electrical contact cleaner
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0102.
Start a case with P0102 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0102?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0102 on specific vehicles
The likely causes shift by model. We’ve written up the patterns we see most:
P0102: common questions
Can I drive with P0102?
No code reading can make that call on its own. Expect some hesitation and a rougher idle; get it cleaned or diagnosed promptly, and fix it before an emissions test. If the engine stalls or hesitates badly, stop driving and have it towed in.
Will cleaning fix a P0102 MAF code?
Often — a dirty sensing element reading low is the most common cause, and proper MAF cleaner frequently restores it cheaply. If it returns, look for an intake leak after the sensor or replace the MAF.
What's the difference between P0101 and P0102?
P0101 is a MAF reading that's out of range/implausible; P0102 is specifically a too-LOW signal. Both are commonly a dirty sensor or an intake issue and are diagnosed the same way.
How much does it cost to fix P0102?
Possibly almost nothing if cleaning works. A replacement MAF is the main cost; an intake-duct fix is modest. Clean and inspect before replacing the sensor.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0102 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0102 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.