P0104 - Mass Air Flow Sensor Circuit Intermittent
The P0104 code indicates that the Powertrain Control Module (PCM) 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 can cause the engine to run rich or lean, leading to performance issues. Common causes include a faulty MAF sensor, wiring issues, or a dirty sensor element.
1. Most Common Causes
- Faulty MAF sensor
- Damaged or corroded wiring/connectors
- Dirty MAF sensor element
- Vacuum leaks
- PCM software issues
2. Symptoms You Will Notice
- Check Engine Light on
- Rough idle or stalling
- Poor acceleration
- Decreased fuel economy
- Black smoke from exhaust (rich condition)
3. 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: Clean the MAF sensor with MAF cleaner and recheck.
Step 4: Test MAF sensor signal with a multimeter or scan tool while tapping the sensor to check for intermittent faults.
Step 5: Check for vacuum leaks and repair as needed.
4. 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 poor engine performance and potential damage to the catalytic converter.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for cleaning or replacing the MAF sensor, plus diagnostic fees if done at a shop.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.