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P1100 OBD-II Trouble Code: Mass Airflow Sensor Intermittent

diagnostic check engine light

P1100 code definition

A P1100 trouble code is stored when the Powertrain Control Module (PCM) detects a Mass Air Flow (MAF) sensor signal that falls above or below the manufacturer calibrated limits. Some other, related trouble codes that might appear alongside a P1100 trouble code include a P1101, P1102, P1103, and P1104 code.

What the P1100 code means

The MAF sensor measures the volume and density of the air entering the engine. This data is used by the PCM to calculate the correct fuel to air mixture so that the engine can operate efficiently while in operation. When the PCM detects a variance in the voltage from the MAF sensor that falls outside of manufacturer's specifications, a P1100 trouble code is stored and the Check Engine light illuminates.

What causes the P1100 code?

Some causes of a P1100 trouble code include a dirty or faulty MAF sensor, a dirty MAF sensor wire. An air leak before or after the MAF sensor can also cause the storage of this code. A short in the MAF sensor harness can also cause a P01100 trouble code.

What are the symptoms of the P1100 code?

Some common symptoms of a P1100 trouble code include trouble stahiccupping vehicle, vehicle stalling, hesitation under load, rough idling, and hiccuping by the engine. In addition, the vehicle can suffer from reduced fuel efficiency.

How does a mechanic diagnose the P1100 code?

To diagnose a P1100 trouble code, a mechanic needs to have an advanced scanner, an oscilloscope, and a digital volt/ohm meter. In addition, they should perform the following steps:

  • Check all of the wiring, connectors, and components associated with the MAF sensor for damage or fault.
  • After replacing all faulty or damaged items, the mechanic should clear the P1100 trouble code and test the system to see if the code returns.
  • If the code returns, the mechanic should next test the MAF sensor using the digital volt/ohm meter, looking for voltage and a ground signal.
  • If neither is detected, the mechanic should disconnect the PCM and related control modules and check the continuity of the MAF sensor with the battery ground, comparing their findings with the manufacturer's specifications.
  • The mechanic might also need to perform a smoke test of the vacuum system to see if there is a leak either after or before the sensor.
  • Another way for a mechanic to check the MAF sensor output is by using an oscilloscope attached to an injector ground terminal to test injector timing. Overlong injector timing can signal that the fuel mixture is either too rich or too lean, a condition usually caused by a faulty MAF sensor.
  • Finally, the mechanic should clear the code again and retest the system to see if it returns.

Common mistakes when diagnosing the P1100 code

Mechanics often make the mistake when diagnosing a P1100 trouble code of replacing the MAF sensor without first checking if there is faulty or damaged wiring within the MAF sensor wiring harness. The result is that the problem remains unfixed and the code returns.

How serious is the P1100 code?

While a P1100 trouble code may not prevent a vehicle from operating, drivers can expect a reduction in the fuel efficiency of the vehicle in situations where the engine is running too rich. It is best to get a P1100 trouble code diagnosed and fixed as soon as possible to avoid the stalling and hard start conditions that often accompany the code storage.

What repairs can fix the P1100 code?

To repair a P1100 trouble code, the mechanic needs to perform the following:

  • Replace any faulty wiring, connectors, or components within the MAF sensor wiring harness.
  • Before replacing the MAF sensor, the mechanic should carefully remove the sensor and clean it using cleaner specially made for cleaning the MAF sensor.
  • Once the sensor is clean completely dry, the mechanic should replace it, clear the code, and test the system to see if the code returns.
  • If the sensor is still not working properly, it should be replaced with a new MAF sensor.
  • If, after performing a smoke test, the vacuum system is found to have leaks, the mechanic should repair any leaks they find.

Additional comments for consideration regarding the P1100 code

Mechanics should keep in mind when removing the MAF sensor to take care not to touch the wires connected to the MAF sensor. While the wires cannot electrocute the mechanic, these wires are delicate and easily broken.

Need help with a P1100 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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