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P0105 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

P0105 is an OBD-II Code that refers to Manifold Air Pressure (MAP) Barometric Pressure Sensor Electrical Circuit Problem

Meaning

A P0105 code is a general diagnostic trouble code that occurs when the PCM/ECM detects a problem with the the MAP sensor voltage signal which is expected to change continually as engine load changes. The PCM in a car needs to keep track of this information since changes in engine load can have an impact on other systems. These factors adjust the timing of fuel injection and ignition.

The barometric pressure sensor is similar to a MAP sensor, but it can detect minute fluctuations in atmospheric air pressure. The only distinction between the two sensors is their position. The two sensors are usually combined into a single sensor in most vehicles.

The PCM maintains an on-board monitor of the MAP/BARO sensors and their circuitry. When the module senses an issue, it activates the check engine light and records P0105 in its memory.

Causes

Common causes for this code include:

  • The MAP sensor vacuum hose has been disconnected or reconnected
  • Faulty MAP sensor 
  • Faulty Throttle Position Sensor 
  • Connectors to the sensors that are broken or faulty
  • Wiring is faulty
  • Open or short circuit
  • The loss of ground to the MAP sensor or TPS
  • Bad PCM (rare)

Symptoms

The symptoms of a P0105 code are:

  • Illuminated Check Engine Light
  • Poor performance
  • Poor idle
  • Erratic acceleration
  • Engine runs rich and backfires as MAP sensor and throttle position sensor are not in sync

Diagnosis

To diagnose a P0105 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect the wiring and connectors for damage.
  3. Check the sensor voltage readings and compare to the manufacturer’s specs.
  4. Check for open or short circuits.
  5. Check for a loss of ground.
  6. Check the PCM for faults.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P0105 code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking the sensor voltage readings.
  • Not checking for open or short circuits.
  • Not checking the PCM for faults.

How serious is this?

A P0105 code is a moderate-to-severe code that should be addressed as soon as possible. When the PCM detects this code, it can impact engine performance and fuel economy.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Repair or replace any wiring that is damaged
  • Check the sensor voltage readings and compare to the manufacturer’s specs
  • Check for open or short circuits
  • Check for a loss of ground
  • Replace the MAP sensor or BARO sensor
  • Replace the PCM (rare)

Related codes

A P0105 is related to and may be accompanied by the following codes:

P0106 – MAP Sensor Voltage Too High

P0100 – Mass Air Flow Circuit Malfunction

P0103 – MAP Sensor Voltage Too Low

Conclusion

In conclusion, the P0105 code is a diagnostic trouble code that refers to a problem with the MAP sensor voltage signal. There are many potential causes for this code, but some of the most common ones include a faulty MAP sensor, wiring issue, or a loss of ground. The code should be addressed as soon as possible to avoid any negative impact on engine performance or fuel economy.