What does it mean?
The troublecode P0104 is set when the MAF sensor circuit is malfunctioning. This code is similar to P0100 – MAF sensor circuit malfunction. The difference between the two codes is the consistency of the malfunction in the MAF sensor circuit. Troubleshooting will be the same for both codes. For a P0104 code, double check wiring and connector harnesses. When diagnosing MAF sensor codes, understanding fuel trims is very important.
Please see the fuel trims article (P0171): Fuel Trims – Lean Identifying the type of MAF sensor in your car will also aid diagnosis. There are a number of different MAF sensors including the most common hot-wire sensors. Note: Regardless of the code and the system affected, the word “Intermittent” refers to the fact that there is a sporadic, unpredictable, or, well, intermittent fault in that system.
The most likely causes of codes that relate to intermittent faults include poor connections in both live and ground circuits, as well defective switches, relays, and sensors. Intermittent faults can be extremely difficult to trace and fix, since code readers generally do not specify in which part of the circuit the problem lays.
For instance, the fault could be an intermittent interruption of the reference voltage (power supply), or, as often happens, the problem could be an intermittent break in the signal voltage to the PCM (Powertrain Control Module) due to a failing sensor, wiring issues, or defective electrical connector(s).
Note that the word “intermittent” often means different things to different applications; some systems will set a code the first time an intermittent fault occurs, while others will only do so after several failure cycles. In some cases, it may be necessary to allow the fault to worsen before an accurate and definitive repair can be made.