P0101
Fix within a few daysYour engine's computer isn't getting the expected airflow readings from the Mass Air Flow (MAF) sensor.
Code P0101 means your engine's Mass Air Flow sensor isn't reporting expected airflow. Common causes: Dirty/faulty MAF sensor (60%), vacuum leak (20%), dirty air filter (10%). Drivability: Yes, for short trips only. Repair cost: $50-$200 DIY, $150-$500 professional.
Can I Drive With P0101?
Yes, for short trips only
Essential trips under 10 miles, avoid highways and heavy acceleration. Fix within a few days.
Stop driving immediately if: Flashing Check Engine Light, significant power loss, engine stalling frequently, or black smoke from the exhaust.
Symptoms of P0101
- 1Check Engine Light is on
- 2Engine runs rough or idles poorly
- 3Engine stalls, especially at idle
- 4Poor acceleration or hesitation
- 5Reduced fuel economy
- 6Engine may be hard to start
Common Causes of P0101
Parts most likely causing this code, ranked by probability
A dirty or faulty MAF sensor sends incorrect airflow data to the engine computer, causing performance issues.
60% of P0101 cases are fixed by replacing or cleaning the MAF sensor
An unmetered air leak in the intake system after the MAF sensor causes the engine to receive more air than the MAF reports.
20% of P0101 cases are fixed by repairing a vacuum leak
A dirty or clogged air filter restricts airflow to the MAF sensor, leading to inaccurate readings.
10% of P0101 cases are fixed by replacing a dirty air filter
Leaks in the intake ducting or obstructions can disrupt smooth airflow across the MAF sensor.
5% of P0101 cases are fixed by repairing an intake system issue
Damaged wiring or a corroded connector to the MAF sensor can interrupt the signal to the engine computer.
4% of P0101 cases are fixed by repairing MAF sensor wiring
A rare internal fault in the ECM can cause it to misinterpret MAF sensor signals.
1% of P0101 cases are fixed by replacing the ECM
Check These First (Before Buying Parts)
- Inspect the air filter for dirt or obstructions and replace if needed.
- Visually check all intake hoses and clamps between the air filter box and the engine for cracks, looseness, or disconnections.
- Carefully clean the MAF sensor with MAF sensor cleaner spray, ensuring it's completely dry before reinstalling.
How to Diagnose P0101
- 1Visually inspect the air intake system for loose clamps, cracks, or disconnected hoses.
- 2Remove and inspect the air filter for dirt or obstructions; replace if necessary.
- 3Carefully remove the MAF sensor and clean it with MAF sensor cleaner spray.
- 4Check the MAF sensor wiring harness and connector for damage, corrosion, or loose pins.
- 5Use a scan tool to monitor MAF sensor readings (grams/second) at idle and during acceleration.
- 6Perform a smoke test on the intake system to identify any vacuum leaks.
P0101 on Popular Vehicles
Ford F-150
2004-2024Ford F-150s are particularly sensitive to MAF sensor contamination, especially from oiled aftermarket air filters. Inspecting and cleaning the MAF sensor and checking for intake manifold vacuum leaks are critical first steps.
75% fixed by cleaning/replacing MAF or fixing vacuum leak
Honda Accord
2003-2024Honda Accords often experience P0101 due to a dirty MAF sensor from neglected air filter maintenance or minor vacuum leaks around the intake manifold gasket or PCV system.
70% fixed by cleaning/replacing MAF or replacing air filter
Toyota Camry
2007-2024Toyota Camrys can trigger P0101 from a dirty MAF sensor or small cracks in the intake air ducting after the MAF sensor. Cleaning the MAF sensor is a highly effective initial diagnostic step.
65% fixed by cleaning MAF or repairing intake duct
Frequently Asked Questions
What does P0101 mean?
P0101 indicates that the Mass Air Flow (MAF) sensor's signal is out of the expected range compared to other engine sensors and conditions. This means the engine computer isn't getting accurate information about how much air is entering the engine.
Can I drive with P0101?
Yes, for short trips only. You can drive your vehicle, but expect reduced engine performance, poor fuel economy, and potential stalling. Prolonged driving with this code can lead to further issues, especially with your catalytic converter.
Will P0101 clear itself?
No, P0101 will not clear itself. While cleaning the MAF sensor or fixing a vacuum leak might resolve the underlying issue, the Check Engine Light will remain on until the code is manually cleared with a scan tool or after several drive cycles if the problem is fully resolved and no longer detected.
How do I fix P0101 myself?
Start by inspecting and replacing a dirty air filter. Then, carefully clean the MAF sensor with a specialized MAF sensor cleaner. Check all intake hoses and clamps for leaks or cracks. If these steps don't work, you may need to replace the MAF sensor.
How much does it cost to fix P0101?
DIY repair costs for P0101 range from $50-$200, primarily for a new MAF sensor or MAF cleaner and an air filter. Professional repair costs typically range from $150-$500, including diagnosis, parts, and labor.
P0101 keeps coming back - why?
If P0101 keeps returning, it indicates the root cause was not fully addressed. Common reasons include an overlooked vacuum leak, a faulty MAF sensor that was only cleaned but not replaced, a persistent issue with the air intake system, or a wiring problem that was not properly repaired.
Will P0101 fail emissions/smog test?
Yes, P0101 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on automatically results in a failure in most jurisdictions, and the underlying issue affects your vehicle's emissions output.
What's the difference between P0101 and P0102?
P0101 indicates a MAF sensor performance issue, meaning the sensor's reading is inconsistent or out of expected range. P0102 indicates a MAF sensor low input, meaning the sensor is reporting a consistently low voltage or airflow reading, often suggesting a circuit open or a completely failed sensor.
P0101 on Ford F-150?
P0101 is common on Ford F-150 trucks, especially those with aftermarket oiled air filters that can contaminate the MAF sensor. Cleaning the MAF sensor and ensuring a clean, dry air filter is often the first step. Vacuum leaks in the intake manifold or PCV system are also frequent culprits on these vehicles.
Questions to Ask Your Mechanic
Did you check for vacuum leaks using a smoke machine?
Good answer: Yes, we performed a smoke test on the entire intake system and found no leaks. We also checked the PCV system.
What were the MAF sensor readings at idle and 2500 RPM?
Good answer: At idle, the MAF was reading X grams/second, and at 2500 RPM, it was Y grams/second. These readings were outside the manufacturer's specified range for your vehicle.
Repair Cost Estimate
DIY Repair
Parts only
$50-$200
Shop Repair
Parts + labor
$150-$500
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
0.5-2 hours
Intermediate - requires basic hand tools, a MAF sensor cleaner, and ideally an OBD-II scan tool to monitor live data and clear codes.
Cost of Waiting
Ignoring P0101 leads to continued poor fuel economy and reduced engine performance. The engine running too rich or too lean can damage your catalytic converter, turning a $50 MAF sensor cleaning into a $1,200-$2,500 converter replacement.
While You're In There...
It's often removed to access the MAF sensor and a dirty filter is a common cause of P0101. Replacing it prevents future issues and ensures proper airflow.
If you're diagnosing vacuum leaks, these gaskets are a common failure point and replacing them while the intake is apart saves labor.
The PCV system is a common source of vacuum leaks and is often easily accessible when working on the intake system.
Tools You'll Need
- OBD-II Scan Tool
- MAF Sensor Cleaner Spray
- Screwdriver set
- Socket set
- Multimeter (for advanced diagnostics)
- Smoke machine (for advanced diagnostics)
P0101 is a very common code, and most repairs involve a simple cleaning or replacement of the MAF sensor, getting your engine running smoothly again.
- Family-owned since 1957
- 990,000+ happy customers
- Fast nationwide shipping
- Easy returns
Your Next Steps
Step 1: Check your air filter and replace it if it's dirty. Then, carefully clean your MAF sensor with MAF sensor cleaner.
Step 2: If cleaning the MAF sensor and replacing the air filter doesn't fix the code, thoroughly inspect all intake hoses and vacuum lines for cracks or loose connections. Repair any leaks you find.
Step 3: If the code persists after checking for leaks and cleaning/replacing the air filter, you will likely need to replace the Mass Air Flow sensor itself. Use a quality aftermarket or OEM replacement part.