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OBD-II fault code definitions, symptoms, causes, and step-by-step diagnostics.
Standardized generic DTCFuel & air metering

P0105 — Manifold Absolute Pressure/Barometric Pressure Sensor Circuit

P0105 is the standardized powertrain DTC for “Manifold Absolute Pressure/Barometric Pressure Sensor Circuit.” The code identifies the monitored condition; it does not by itself prove which part failed.

Standardized generic definition
Manifold Absolute Pressure/Barometric Pressure Sensor Circuit
DTC category
Fuel & air metering
Diagnostic priority
Moderate. Incorrect airflow/load data can cause poor drivability, incorrect fueling, reduced power, or secondary mixture codes.
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What P0105 means

P0105 is the standardized powertrain DTC for “Manifold Absolute Pressure/Barometric Pressure Sensor Circuit.” The code identifies the monitored condition; it does not by itself prove which part failed.

Start with the stored data and the simplest external checks before replacing the component named in the code.

Possible symptoms

  • Check Engine Light
  • Rough idle, hesitation, stalling, or reduced power
  • Poor fuel economy
  • Possible lean/rich or load-related companion codes

Causes to test

These are diagnostic possibilities, not a statistical parts-replacement ranking. Vehicle-specific service information takes priority.

  • Airflow/pressure sensor contamination, bias, or internal fault
  • Intake duct leak, restriction, or incorrectly installed air filter/ducting
  • Connector, reference-voltage, ground, or signal-circuit problem
  • Vacuum/PCV leak or other unmetered air
  • Barometric/MAP/MAF values that disagree because of an engine breathing or exhaust restriction problem

Step-by-step diagnostic workflow

  1. Compare the sensor reading with key-on/engine-off and known operating-condition expectations.
  2. Inspect intake ducting, air filter, clamps, PCV/vacuum connections, and sensor installation before replacing parts.
  3. Compare MAF/MAP/barometric pressure, RPM, calculated load, and fuel trims together rather than judging one PID alone.
  4. For circuit low/high/open codes, verify supply/reference, ground, and signal voltage using the OEM diagram.
  5. For range/performance codes, check for contamination, intake/exhaust restrictions, leaks, and vehicle-specific calibration/TSB conditions.
  6. Clear codes only after repair, then complete an appropriate drive cycle and verify the code and symptoms do not return.
Preserve evidence: EPA OBD guidance emphasizes that stored DTCs and freeze-frame data are important to proper diagnosis. Save them before clearing codes.

Scan data worth checking

  • MAF airflow and/or MAP pressure
  • Barometric pressure
  • RPM and calculated load
  • STFT/LTFT
  • Throttle position and intake-air temperature

Severity and drivability

Moderate. Incorrect airflow/load data can cause poor drivability, incorrect fueling, reduced power, or secondary mixture codes.

Stop driving and investigate immediately if there is a flashing MIL, oil-pressure warning, overheating, fuel leakage, severe misfire, major loss of power, abnormal mechanical noise, or a transmission that is slipping badly.

Common diagnostic mistakes

  • Replacing or cleaning a MAF/MAP sensor without checking intake leaks and scan-data plausibility
  • Using a generic grams-per-second rule without accounting for engine displacement/load
  • Ignoring a restricted intake/exhaust or incorrect aftermarket intake configuration

Related generic codes

P0104 — Mass or Volume Air Flow Sensor A Circuit IntermittentP0106 — Manifold Absolute Pressure/Barometric Pressure Sensor Circuit Range/PerformanceP0103 — Mass or Volume Air Flow Sensor A Circuit HighP0107 — Manifold Absolute Pressure/Barometric Pressure Sensor Circuit LowP0102 — Mass or Volume Air Flow Sensor A Circuit LowP0108 — Manifold Absolute Pressure/Barometric Pressure Sensor Circuit High

Source and accuracy notes

Generic DTC structure and standardized definitions are governed by SAE J2012/J2012DA. Actual enable criteria, thresholds, circuit pinouts, test values, software conditions, and repair procedures vary by vehicle. Use current OEM service information for the exact year/engine/calibration and check applicable manufacturer technical service bulletins. See the site methodology and primary-reference policy.