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On-board diagnostic or OBD-II codes are standard trouble codes that can give you or a mechanic an idea of what may be wrong with your vehicle. P0105, in particular, is an engine trouble code related to a possible issue with your vehicle’s manifold absolute pressure (MAP) sensor and/or barometric pressure (BARO) sensor.

Here is some basic information that may help you understand what retrieving a P0015 code from a scan tool may mean for your vehicle. 

What Does the P0105 Code Mean?

Diagnostic Trouble Code (DTC) P0105 stands for “Manifold Absolute Pressure/BARO Circuit Malfunction.” The code is logged once the vehicle’s powertrain control module (PCM) perceives a possible issue with the MAP sensor or BARO sensor circuit.

mechanic using scan tool for auto repair diagnostics
Code P0105 may register if the vehicle’s powertrain control module (PCM) perceives a possible issue with the MAP sensor or BARO sensor circuit.

A MAP sensor is used by the PCM to monitor engine load.  This sensor is designed to react to changes in engine manifold pressure. An engine that is under load is expected to have greater manifold pressure compared to a coasting engine. The MAP sensor voltage signal is expected to change continually as engine load changes.

A vehicle’s PCM needs to monitor this data because changes in engine load affects other systems in the vehicle. These changes may also affect fuel injection and ignition timing.

 A BARO sensor typically works just like a MAP sensor, but it can detect more minute changes in atmospheric air pressure.

The only difference between the two sensors is their location. A MAP sensor is usually connected to the manifold. On the other hand, a BARO sensor is vented directly to the atmosphere. In most vehicles, the two sensors are integrated into a single sensor.

The PCM monitors the integrity of the MAP/BARO sensors and their circuit(s). When the module detects a problem, it turns on the check engine light and stores P0105 in its memory.

Vehicles that are prone to code P0105 include various models of Chevrolet (especially Chevy Trailblazer), Mercedes Benz, Opel, and Nissan.

Note: The definition of code P0105 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0105 Code?

Here are the possible triggers of this trouble code: 

  • Disconnected or plugged MAP sensor vacuum hose 
  • Faulty MAP sensor
  • Faulty BARO sensor 
  • Malfunctioning throttle position sensor (TPS)
  • Circuit issues, such as damaged wires or poor connections 
  • Intake manifold vacuum leaks 
  • Faulty PCM 

What are the Common Symptoms of a P0105 Code?

Below are some of the symptoms related to this error code:

  • Illuminated check engine light
  • Poor engine performance
  • Engine misfire when under load or when idle
  • Engine fails to idle
  • Engine backfire (through the tailpipe) 

In some cases, your vehicle may not show any noticeable symptoms except for an activated check engine light. 

man checking why engine fails to idle
An engine that fails to idle is one of the symptoms of code P0105.

How to Diagnose the P0105 Code 

Diagnosing any vehicle issue is challenging, especially if you don’t have the automotive expertise and the right tools to get the job done. Given that there are several possible issues that may cause this error code, identifying the root cause of the problem may not be easy.

If tinkering with cars is not your thing, it would be best to take your vehicle to an auto repair shop. A mechanic would know how to properly diagnose the problem and rule out any other issues that may be causing similar symptoms. 

If you plan on troubleshooting the P0105 fault code yourself, be sure to consult a vehicle-specific repair manual and/or an online repair database for helpful tips and information about diagnosing a MAP sensor circuit error code. 

How to Fix the P0105 Code

P0105 may be a standard diagnostic trouble code, but the diagnostic and repair procedures may vary depending on the specific vehicle that you’re trying to fix.

Remember that modern vehicle systems are complex, and there may be differences in engine specifications and circuitry depending on the type of vehicle that you own. For example, a confirmed fix for a Toyota P0105 code may not resolve a code P0105 on a Nissan.

A vehicle-specific repair manual can help you identify the appropriate repair procedure for your vehicle. You may also subscribe to an online repair database to get factory repair information.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic.

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