Mass Air Flow (MAF) Circuit Malfunction
A P0100 Indicates that the PCM has detected a voltage reading that is not normal for the mass air flow sensor.
Code Set Parameters
Typical code setting parameters consist of voltage and/or resistance readings that vary by greater than 10-percent than that of the manufacturer’s specified reference voltage.
Symptoms include failure to accelerate, decreased fuel efficiency, and a service engine soon light.
Common causes of this code are a disconnected plug at the MAF sensor, moisture or debris that has contaminated the vane of the MAF, a faulty MAF, a cracked or broken air inlet pipe, clogged air filter element, or faulty PCM. PCM failures are rare.
Often expensive MAF sensors are replaced when a simple cleaning of the MAF “hot wire” could rectify the condition. Corroded wiring and/or connectors have also been reported by technicians.
- Begin your diagnosis by visually inspecting all wiring and connectors
- Look for shorted or burned wiring and replace circuitry and connectors as required
If the system wiring, connectors, and components appear to be in normal working order, connect the scanner to the diagnostic connector and record all stored trouble codes and freeze frame data
- This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
- After the codes are cleared, operate the vehicle to see if the code returns
- If the code fails to immediately return, you may have an intermittent condition
- Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made.
Determine whether there is a malfunction in MAF system circuitry, a problem with unmetered air entering the engine, or a problem with an insufficient air supply to the engine
- Check for a clogged air filter element, broken, pinched, or disconnected air inlet pipe, or a vacuum leak prior to beginning an electrical diagnosis
- If these items are found to be in proper working order, check for power and ground at the MAF sensor, as well as sensor voltage to the PCM
- Visually inspect the vane or hot wire of the MAF itself for signs of foreign dirt or other debris
- This can be removed by carefully using an approved chemical cleaner and a cotton swab, then blowing dry with compressed air