Ford DTC P0100 Decoded: Mass Air Flow Circuit

Code Meaning: Mass Air Flow Circuit

What’s Wrong: The MAF measures the amount of air entering your Ford’s engine. This information is used by the ECM to calculate the right amount of fuel and ignition timing. The P0100 code indicates that the ECM detects an electrical circuit issue between the MAF and ECM.

Ford MAF sensor


  • Check engine light/code stored in bank
  • Poor engine performance
  • Stalling or hesitation
  • Poor fuel economy

Common Causes:

  • Faulty MAF Sensor
  • Unplugged MAF sensor
  • Damaged wiring
  • Loose or corroded terminals in the MAF circuit

Diagnosis And Repair

The first step is to inspect the wiring and connection to the MAF. If there are no signs of damage to the wiring harness going in to the MAF and the sensor is properly plugged in, the next thing you need to do is clean the MAF and see if that remedies the issue. Cleaning the MAF is fairly easy:

1. Remove the connecting air intake, unscrew the metal band holding the MAF to the plastic intake duct and remove the MAF from the car. Use MAF sensor cleaning spray — yes, there is such a thing — and follow as instructed.

2. Do NOT use carb, brake cleaner, or anything of the sort when cleaning the MAF as it will fry the sensor. Never attempt to use a tool to agitate for the cleaning process. Even a cotton swab can break the wires inside. Also, be very, very careful when handling the MAF as the tiny sensors inside are very delicate and break easily.

If you clean the MAF, check the wiring for damage, and make sure the sensor is plugged-in correctly. If the code keeps coming back once it has been erased from the ECM bank, it’s likely that the MAF itself is in need of replacement. An MAF is not a part that malfunctions very often, but it can happen over time, especially if it remains dirty for prolonged periods or something made it past the air intake filter and damaged the wires inside.

Should you need to replace the MAF, simply use the method for removal mentioned for cleaning and then replace it with an OEM unit. This is a very easy job, and the part is fairly inexpensive. Remember to only use an OEM replacement because cheap aftermarket units are not going to perform up to the same standards as they are usually much lower grade — they’re also prone to premature failure.

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