P0107 serious

Manifold Absolute Pressure Sensor Circuit Low Input

What does P0107 mean?

The P0107 code means the vehicle's onboard diagnostic system has detected: Manifold Absolute Pressure Sensor Circuit Low Input. This is a serious severity code.

Common Symptoms

  • Check Engine Light on
  • Engine runs rich
  • Poor fuel economy
  • Rough idle
  • Potential black smoke

Probable Causes (Ranked by Likelihood)

  • Faulty MAP sensor output voltage too low Very High
  • Open circuit or short to ground in signal wire High
  • Vacuum line disconnected causing extreme low reading Moderate
  • Failed sensor ground Low

Step-by-Step Diagnostic Procedure

  1. With key on, check MAP sensor signal voltage. Below 0.3V at atmospheric pressure indicates a low-output fault.

  2. Check wiring for open circuits between MAP sensor and PCM.

  3. Verify 5V reference supply to MAP sensor.

  4. Swap with a known-good sensor if wiring checks out.

  5. Inspect vacuum port for blockage (low vacuum reference causes a low reading).

Frequently Asked Questions

A low MAP signal makes the engine run rich -- why?

Low MAP voltage tells the ECU that vacuum is extremely high, suggesting a very light load. The ECU reduces fuel, but since actual vacuum is normal, the air-fuel mixture is thrown off, often causing a rich condition as the fuel trims compensate.

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