P0104 Code – Mass Air Flow Circuit Intermittent

The P0104 diagnostic trouble code (DTC) indicates that the engine control unit (ECU) has detected an intermittent or unstable signal from the Mass Air Flow (MAF) sensor circuit.

This means the signal from the MAF sensor is not consistent – it may drop, spike, or disconnect temporarily.

The ECU relies on stable airflow data to calculate the correct air-fuel mixture, so fluctuating readings can lead to improper engine operation.

Symptoms of Code P0104

Common symptoms include:

• Check Engine light ON

• Engine hesitation

• Jerking during acceleration

• Rough idle

• Loss of power

• Engine stalling (in some cases)

• Inconsistent performance

This code often causes random and unpredictable behavior.

Common Causes of P0104

Typical causes include:

• Faulty or failing MAF sensor

• Loose or damaged wiring

• Intermittent electrical connection

• Corroded connectors

• Vacuum leaks

• Dirty MAF sensor

• Air intake system issues

In many cases, the issue is caused by bad contact in the connector.

How Serious Is Code P0104

The P0104 code is considered a moderate issue, but it can become serious if ignored.

Because the problem is intermittent, it can:

• be difficult to diagnose

• worsen over time

• lead to unstable engine performance

How to Diagnose Code P0104

Diagnosis steps:

1. Scan the vehicle with an OBD2 scanner

2. Monitor live MAF data for fluctuations

3. Inspect wiring and connectors

4. Wiggle test the wiring harness

5. Check for vacuum leaks

6. Clean the MAF sensor

7. Test sensor signal stability

How to Fix Code P0104

Possible solutions include:

• cleaning the MAF sensor

• repairing or replacing damaged wiring

• securing loose connectors

• replacing faulty MAF sensor

• fixing air intake leaks

• resetting ECU after repair

Vehicles Commonly Affected by P0104

This code appears on a wide range of vehicles:

• BMW

• Audi

• Volkswagen

• Ford

• Opel

• Toyota

• Nissan

Any vehicle equipped with a MAF sensor can trigger this code.

FAQ – P0104 Code

Can I drive with code P0104?

Yes, but the engine may behave unpredictably and performance will suffer.

Is P0104 hard to diagnose?

Yes, because the issue is intermittent and may not appear constantly.

Can loose wiring cause this code?

Absolutely. This is one of the most common causes.