P0102 MAF Sensor Signal Too Low
Get it checked soon
The mass airflow (MAF) sensor signal is too low or missing. That is usually a connector, wiring or a dirty sensor, not a real lack of air. The car usually still runs, but not well.
- Safe to drive?
- Yes, gently, fix soon
- Typical cost at a shop
- $274-$381 RepairPal national averages, parts and labor
- Emissions test
- Yes, while the check engine light is on, most OBD emissions tests fail the car.
What it means
The MAF sensor tells the computer how much air enters the engine, and every fuel decision starts from that number. P0102 means the signal is too low or dead. That is nearly always electrical or dirt on the sensor. The computer then estimates airflow, so the engine runs, but not well.
The technical version
The computer compares the MAF signal with what it expects from rpm, throttle and manifold pressure. A signal below the valid range for the conditions sets P0102. P0101 is a signal that is in range but does not make sense; P0103 is a signal that is too high.
Official name: Mass or Volume Air Flow Circuit Low Input.
Symptoms
- Hesitation or weak power.
- Rough idle.
- Worse fuel economy.
- Lean, rich or misfire codes may follow.
Causes, most likely first
| Cause | How likely | How to tell |
|---|---|---|
| A loose, corroded or damaged MAF connector or wiring | most common | The reading drops out when you move the connector. |
| A dirty MAF sensor, including oil from an over-oiled air filter | common | Reading low but not zero; an oiled aftermarket filter. |
| A failed MAF sensor | common | Reading stays near zero with good wiring. |
| Air ducting problems around the sensor | rare | A loose or cracked intake duct. |
How likely is our ranking from repair data and common practice, not a published rate.
What the live data shows
The MAF reading in grams per second is the direct check. A healthy engine idles at a small, steady number that climbs smoothly with revs. With P0102 it sits near zero or stays flat as rpm rises. Check calculated load and fuel trims too: trims swinging hard while the MAF reads nothing confirms the sensor.
What to check first, in order
-
Unplug and reseat the MAF connector. Look for bent pins and corrosion.
The most common cause, and free.
What the data shows: The MAF reading should appear and rise with revs.
Cost: free
-
Clean the sensor with MAF cleaner. Do not touch the element.
Dirt lowers the signal.
What the data shows: Idle MAF should rise a little.
Cost: a can of MAF cleaner
-
Check the wiring for damage.
Chafed wires cause a low signal.
What the data shows: Watch for drop-outs while you move the harness.
Cost: free to look
-
Replace the MAF sensor.
If wiring and cleaning do not help.
What the data shows: Reading tracks rpm smoothly.
Cost: $274-$381 at a shop (Mass airflow (MAF) sensor replacement, RepairPal)
Is it safe to drive?
Get it checked soon
Yes, gently, fix soon. The engine runs on a backup estimate.
The car usually drives on estimated airflow: expect hesitation, weak power, rough idle and worse economy. It will not strand you in most cases, but do not leave it long; lean, rich and misfire codes tend to follow.
Stop driving and get help if
- The engine stalls in traffic.
- The check engine light flashes.
What it costs
| Repair | Typical cost |
|---|---|
| Mass airflow (MAF) sensor replacementRepairPal, updated September 3, 2026 | $274-$381 |
National averages for the full job at a shop, parts and labor, from RepairPal (updated September 3, 2026). Your price depends on the car and the area. Many of the first checks on this page cost nothing with a scanner. MAF sensor replacement was CarMD's number 4 check engine repair in 2025, at an average of $346. CarMD averages come from a different method (repairs reported by its users), so they can sit below RepairPal's shop estimates.
Sources for the notes: CarMD 2026 Vehicle Health Index (press release, April 22, 2026).
Can I clear it? Will it come back?
After the fix, clear the code and drive. The MAF reading should follow rpm on the first drive.
Will it fail an emissions test?
Yes, while the check engine light is on, most OBD emissions tests fail the car.
Related codes
Also related, no guide yet: P0101, P0103.
How Obie handles P0102
Obie reads the MAF value against rpm and load, and tells you whether it looks like wiring, dirt or a failed sensor. Obie is part of ScanMyCar Pro. Codes and live sensors are free.
Questions people ask
Can I clean the MAF sensor to fix P0102?
Sometimes. Check the connector first, then clean the sensor with MAF cleaner only.
Can I drive with P0102?
Usually yes, gently. Fix it soon so other codes do not pile on.
Can a dirty air filter cause P0102?
Rarely on its own. An over-oiled aftermarket filter can coat the sensor.
Sources
- RepairPal: P0102 code page repairpal.com
- RepairPal: Mass airflow (MAF) sensor replacement (updated September 3, 2026) repairpal.com
- CarMD 2026 Vehicle Health Index (press release, April 22, 2026) prnewswire.com
- Texas DPS emissions testing FAQ dps.texas.gov
- Arizona myazcar.com: OBD and the check engine light myazcar.com
A guide, not a diagnosis. This page describes what P0102 generally means across OBD2 cars. What is actually wrong with your car depends on its live data and its history, and any repair decision deserves a proper diagnosis, whether that is you with a scanner or a professional with a lift.
