P0100 – Mass Air Flow (MAF) Sensor Circuit Malfunction

Description

The P0100 trouble code indicates that the Engine Control Module (ECM) has detected a malfunction in the Mass Air Flow (MAF) sensor circuit. The MAF sensor measures the amount of air entering the engine, allowing the ECM to calculate the correct fuel injection and engine load.

Common Causes

Faulty MAF sensor, dirty sensor element, damaged wiring, loose or corroded connector, air intake leaks, incorrect air filter installation, short or open circuit, or a faulty ECM (rare).

Symptoms

Check Engine Light ON, rough idle, poor acceleration, loss of engine power, engine hesitation, poor fuel economy, and black smoke in some cases.

Electrical Wiring Diagram

             ECM / PCM
                |
          5V Reference
                |
                |
          +-----------+
          | MAF Sensor|
          +-----------+
                |
          Signal Output
                |
          Sensor Ground


 Air Filter
    |
 Intake Pipe
    |
 MAF Sensor
    |
 Throttle Body
    |
 Engine

Live Data Check

Monitor MAF Air Flow (g/s) using a scan tool. Check that the value increases smoothly when engine RPM increases. Compare MAF readings with engine load and RPM. An incorrect reading, zero value, or unstable signal may indicate a MAF sensor or wiring problem.

Estimated Repair Cost

Typical repair costs range from $50 to $400, depending on whether the problem is cleaning, wiring repair, or MAF sensor replacement.

Severity

Moderate. The vehicle may continue running, but incorrect airflow measurement can cause poor performance, increased fuel consumption, and emissions problems.

Recommended Fix

Inspect the MAF sensor connector and wiring, check for intake air leaks, clean the MAF sensor using proper cleaner, verify live data readings, replace the sensor if faulty, clear the DTC, and confirm the repair.