P0100
Mass or Volume Air Flow "A" Circuit Malfunction
The engine computer is not receiving a correct signal from the mass air flow sensor circuit. This can be caused by a bad MAF sensor, unplugged connector, damaged wiring, or an intake problem affecting airflow measurement.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $0-$180
- SHOP
- $120-$400
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- MAF sensor unplugged or failed
- Damaged, loose, or corroded MAF connector or wiring
- Dirty or contaminated MAF sensing element
Typical repair cost
DIY usually runs $0-$180. Typical shop repair lands around $120-$400, depending on the root cause.
01 / Definition
P0100 means the PCM has detected a malfunction in the mass air flow sensor A circuit. The MAF sensor tells the PCM how much air is entering the engine so fuel delivery can be calculated correctly. If the signal is missing, implausible, or electrically faulty, the PCM stores P0100 and may switch to backup airflow values.
02 / Drive status
With caution. Short trips are often possible, but the engine may idle poorly, hesitate, stall, or lose power. Repair it soon because incorrect airflow data can make fuel control unstable.
03 / Symptoms
- Check engine light
- Rough idle
- Poor acceleration
- Engine hesitation
- Stalling
- Hard starting
- Reduced fuel economy
- Rich or lean running
04 / Causes
| 1 | MAF sensor unplugged or failed | high |
|---|---|---|
| 2 | Damaged, loose, or corroded MAF connector or wiring | high |
| 3 | Dirty or contaminated MAF sensing element | medium |
| 4 | Air intake duct, intake boot, or air filter housing problem | medium |
| 5 | Poor power supply or ground to the MAF circuit | medium |
| 6 | PCM fault | low |
05 / Diagnostic sequence
- 01Confirm P0100 and check for related codes such as P0101, P0102, P0103, lean codes, or throttle codes.
- 02Inspect the MAF sensor connector to make sure it is fully seated and not contaminated or corroded.
- 03Inspect the wiring harness for rubbed insulation, broken wires, or previous repair damage.
- 04Check the intake duct, air box, and clamps for looseness, cracks, or parts left disconnected after service.
- 05Look at live MAF data during idle and light throttle to see whether the signal is present and believable.
- 06Test the MAF power, ground, and signal circuits with a wiring diagram and meter.
- 07Clean the sensor only with proper MAF cleaner if contamination is found.
- 08Replace the sensor only after connector, wiring, and intake checks pass.
06 / Repairs
| 1 | Reconnect the MAF sensor if it is unplugged | $0-$20 |
|---|---|---|
| 2 | Repair damaged wiring, poor grounds, or corroded connector terminals | $10-$150 |
| 3 | Repair loose or cracked intake ducting and air box leaks | $20-$150 |
| 4 | Clean the MAF sensing element with approved cleaner | $10-$20 |
| 5 | Replace the MAF sensor if testing confirms sensor failure | $60-$180 |
07 / Related codes
08 / FAQ
What does P0100 mean?
It means the PCM found a malfunction in the mass air flow sensor circuit.
Can a loose MAF connector cause P0100?
Yes. A loose or unplugged connector is a common cause.
Should I replace the MAF sensor right away?
No. First check the connector, wiring, intake ducting, and sensor contamination.
Can P0100 cause stalling?
Yes. Bad airflow data can make fuel delivery unstable enough to cause hesitation or stalling.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.