Contaminated or failed mass air flow sensor element; Intake air leak between the MAF sensor and throttle body; Damaged or disconnected MAF sensor wiring or connector; Clogged or improperly installed air filter element; Failed MAF sensor internal electronics; High resistance in the sensor ground circuit; Engine computer (ECM) fault, though rare

DTC codes / P01xx · Fuel and air metering / P0102

P0102Mass/Volume Air Flow Circuit Low Input

Q: What does code P0102 mean?

Mass/Volume Air Flow Circuit Low Input. P0102 means the engine computer has detected a low input signal on the mass air flow (MAF) sensor circuit, which measures how much air enters the engine. The computer expects a voltage that rises with airflow, but the signal is below the minimum threshold for the current operating conditions, so the computer cannot trust the airflow measurement.

P0102 means the engine computer has detected a low input signal on the mass air flow (MAF) sensor circuit, which measures how much air enters the engine. The computer expects a voltage that rises with airflow, but the signal is below the minimum threshold for the current operating conditions, so the computer cannot trust the airflow measurement.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illuminated check engine light, often with no other symptoms
Rough idle, stalling, or surging at idle
Hesitation or lack of power during acceleration
Poor fuel economy or rich-running smell
Black smoke from the exhaust in severe cases
Occasional hard starting or engine cranks but won't start

Common causes, most likely first

Contaminated or failed mass air flow sensor element
Intake air leak between the MAF sensor and throttle body
Damaged or disconnected MAF sensor wiring or connector
Clogged or improperly installed air filter element
Failed MAF sensor internal electronics
High resistance in the sensor ground circuit
Engine computer (ECM) fault, though rare

How to diagnose and fix it

Inspect the air intake tract for cracks, loose clamps, or disconnected hoses between the MAF sensor and throttle body
Check the MAF sensor connector for corrosion, bent pins, or loose terminals and verify it is fully seated
Clean the MAF sensor element with a dedicated MAF cleaner following the product instructions, then clear the code and retest
Measure the MAF sensor signal voltage with a scan tool or multimeter and compare to the manufacturer's specification at idle and during a snap throttle test
Check the sensor ground circuit for excessive resistance using a voltage drop test
Replace the MAF sensor if cleaning and circuit checks do not restore a normal signal
Clear the code and perform a road test to confirm the repair and ensure no pending codes return

What a low MAF signal really tells you

A dirty MAF sensor element is the most common cause of P0102, and cleaning it often resolves the code without any parts replacement.
An intake leak downstream of the MAF sensor lets unmetered air into the engine, which can skew the signal low and set this code even when the sensor itself is good.
A clogged air filter or an incorrectly installed filter that seals poorly can reduce airflow across the sensor and trigger a low input code.
P0102 does not always mean the sensor is dead; wiring harness chafing near the connector or a poor ground can produce the same low signal.
After replacing or cleaning the MAF sensor, the engine computer may need a drive cycle or relearn procedure before the code stays cleared.

Can I keep driving with P0102?

You can usually drive the vehicle with P0102, but expect reduced performance and fuel economy, and avoid heavy acceleration or towing until the fault is repaired. If the engine stalls, runs very rough, or shows black smoke, stop driving and have it diagnosed promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.