Mass Air Flow Sensor Circuit Low Input
The P0102 code indicates that the Engine Control Module (ECM) has detected a low voltage signal from the Mass Air Flow (MAF) sensor circuit. This typically means the MAF sensor output is below the expected range (usually below 0.2 volts) or the sensor is not producing any signal. The MAF sensor measures the amount of air entering the engine, and a low input can cause incorrect fuel delivery, leading to poor engine performance.
01. Most Common Causes
- Faulty MAF sensor
- Open or short circuit in MAF sensor wiring or connector
- Dirty or contaminated MAF sensor element
- Intake air leak downstream of MAF sensor
- Faulty ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine stalling or rough idle
- Poor acceleration or hesitation
- Black smoke from exhaust (rich condition)
- Decreased fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect MAF sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Check for intake air leaks between MAF sensor and throttle body.
Step 4: Measure MAF sensor signal voltage with a multimeter at idle (should be 0.5-1.5V) and at 2500 RPM (should increase).
Step 5: Clean the MAF sensor with MAF cleaner if dirty, then retest.
Step 6: If voltage is still low, replace the MAF sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with P0102. The engine may run poorly, stall, or enter limp mode, which can be unsafe. You should diagnose and repair the issue promptly.
How much does it cost to fix?▼
The cost to fix P0102 typically ranges from $50 to $150 for a DIY replacement of the MAF sensor. Professional repair may cost $150 to $300 including labor and parts.