P0102: Air flow sensor circuit low input
The ECU sees a voltage that is too low on the air flow sensor signal. Usually the connector, a broken or earthed wire, or the sensor itself.
| Code | P0102 |
|---|---|
| System | Engine and transmission |
| Group | P01xx, Air and fuel metering |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0102 means
The air flow sensor sends a voltage (or frequency) that rises with the amount of air coming in. If the ECU sees it below what is possible, it treats the circuit as faulty and stores this code. It can also appear if very little air gets in through a blocked filter or duct, but an electrical problem is more usual.
Most common causes
- Loose, corroded or poorly seated sensor connector
- Signal or power wire broken, or chafed and touching earth
- A faulty air flow sensor
- No power to the sensor (fuse or relay)
- Badly blocked air intake or filter
Symptoms
- Engine warning light on
- Loss of power, sometimes with limp mode
- Unstable idle or stalling when you lift off
- Slightly harder starting
Can you drive with P0102?
With care You can drive, but the engine runs on backup values and may feel flat or stall at idle. Get it fixed soon.
Open the bonnetthe in-depth explanation
How to check it
At idle, watch air flow in live data: if it reads close to zero, switch off, unplug and refit the connector, then try again. If nothing changes, have the garage check the sensor’s power supply.
How to read and clear P0102 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0102 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P0100 Mass or volume air flow sensor circuit fault
- P0101 Air flow sensor range or performance problem
- P0103 Air flow sensor circuit high input
- P0104 Air flow sensor circuit intermittent
- P0105 Manifold absolute pressure (MAP) sensor circuit fault
- P0106 Manifold absolute pressure (MAP) sensor range or performance
- P0107 Manifold absolute pressure (MAP) sensor circuit low
- P0108 Manifold absolute pressure (MAP) sensor circuit high
- P0109 Manifold absolute pressure (MAP) sensor circuit intermittent
- P0110 Intake air temperature sensor circuit fault
What does code P0102 mean?
The air flow sensor sends a voltage (or frequency) that rises with the amount of air coming in. If the ECU sees it below what is possible, it treats the circuit as faulty and stores this code. It can also appear if very little air gets in through a blocked filter or duct, but an electrical problem is more usual.
Can you drive with P0102?
You can drive, but the engine runs on backup values and may feel flat or stall at idle. Get it fixed soon.
How do you clear P0102?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0102 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
