P0101

Mass or Volume Air Flow Sensor A Circuit Range/Performance

Fuel & air metering Generic OBD-II High

What it means

P0101 means the mass airflow (MAF) sensor's reading doesn't match what the engine control module expects for current conditions. The MAF measures incoming air so the ECM can add the right amount of fuel; when the signal is off — usually from a dirty sensor or an intake leak — the mixture drifts and the engine can hesitate, idle rough, and lose economy.

High

Can I keep driving? Usually drivable, but the engine may hesitate, idle rough, or lack power because the ECM is metering fuel from a bad airflow reading — get it looked at soon.

Real-world scan data

Seen in

9,404

scans in the past year

Found in

1.5%

of scans

Appears alongside · share of P0101 scans

P0113in 44.3% of scans

P0103in 16.6% of scans

P0102in 8.9% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Hesitation or lack of power on acceleration
Rough or unstable idle
Poor fuel economy

Common causes

Most likely first

Dirty or contaminated MAF sensor element (very common)Likely
Vacuum or intake leak downstream of the sensor (unmetered air)Common
Loose or split air-intake duct / clogged air filterCommon
Damaged or failing MAF sensorLess often
Wiring or connector fault in the MAF circuitLess often
Failed engine control module (rare)Less often

How to diagnose & fix

Work through it in order

Check the air-intake duct for splits or loose clamps and replace a dirty air filter first.
Clean the MAF sensor element with dedicated MAF cleaner (never touch it).
Inspect for vacuum leaks between the MAF sensor and the throttle body.
Check the MAF connector and wiring; compare live airflow readings against spec.
If the reading is still out of range, replace the MAF sensor. Clear and re-test.

P0101 by make

Based on commonly reported failure patterns across owner and repair communities, not on our scan data.

BMW

On BMWs a failing MAF sensor is a well-known cause, along with cracked intake boots. Both are usual suspects before suspecting anything deeper.

Chevrolet

On Chevrolet trucks and cars a dirty MAF sensor is a common cause, especially after an oiled aftermarket air filter. Check the intake tube for leaks too.

Ford

Commonly reported on Ford trucks and SUVs from a dirty MAF sensor or an air leak after the sensor. Cleaning the sensor and checking the intake tube is a cheap first step.

Nissan

On Nissans a dirty or aging MAF sensor is a commonly reported cause. Cleaning it and checking the intake tube is a sensible start.

Subaru

On Subarus a dirty MAF sensor or an intake leak is commonly behind this. Cleaning the sensor is a quick first step.

Toyota

On Toyotas a dirty MAF sensor is the usual cause, particularly with aftermarket air filters. Clean it with MAF-specific spray before replacing.

Volkswagen

On VW and Audi models a failing MAF sensor or a split in the intake tube or PCV connection is commonly reported. Cleaning or replacing the sensor is usually straightforward.

FAQ

Quick answers

Is it safe to drive with P0101?+

Short trips are usually fine, but a bad airflow signal can cause hesitation and poor economy, and a very off reading can stall the engine. Fix it soon.

Can I just clear P0101?+

You can, but it returns once the ECM re-runs the airflow check unless the dirty sensor, intake leak, or duct problem is corrected.