P0104 - Mass Air Flow Sensor Circuit Intermittent
The P0104 code indicates that the Engine Control Module (ECM) has detected an intermittent signal from the Mass Air Flow (MAF) sensor circuit. This sensor measures the amount of air entering the engine to determine the correct fuel mixture. An intermittent fault means the signal is erratic or drops out temporarily, often due to wiring issues, loose connections, or a failing sensor. This can cause drivability problems and trigger the Check Engine Light.
01. Most Common Causes
- Faulty MAF sensor
- Loose or corroded electrical connector
- Damaged wiring or short circuit in the MAF circuit
- Intake air leak after the MAF sensor
- Dirty or contaminated MAF sensor element
02. Symptoms You Will Notice
- Check Engine Light on
- Engine stalling or rough idle
- Hesitation or surging during acceleration
- Poor fuel economy
- Black smoke from exhaust (rich mixture)
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect MAF sensor connector and wiring for damage or corrosion.
Step 3: Check for intake air leaks downstream of the MAF sensor.
Step 4: Test MAF sensor signal with a scan tool or multimeter while engine is running.
Step 5: Clean the MAF sensor with MAF cleaner if dirty, then retest.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the intermittent signal can cause stalling or poor performance, potentially leading to unsafe driving conditions.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. If the MAF sensor needs replacement, parts range from $80-$200 plus labor. Cleaning the sensor is cheaper, around $10 for cleaner.