P0105 Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction

P0105 points to a manifold absolute pressure or barometric pressure circuit malfunction. The pressure input used for load calculation is unreliable.

Code details

Generic OBD-II · P0

System: Fuel / Air
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the MAP sensor before checking the vacuum source, reference circuit, and key-on pressure plausibility.

Symptoms of P0105

Check-engine light on, sometimes with rough or uneven running.
Hesitation, surging, or a noticeable change in fuel economy.
Occasionally hard starting or a smell of unburnt fuel.

Common causes of P0105

A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
Wiring, connector, or fuel-delivery problems that skew the reading.

Useful checks before replacing parts

Compare MAP, BARO, throttle angle, RPM, engine load, intake temperature, and key-on engine-off pressure readings.
Check sensor reference voltage, ground, signal voltage, connector condition, vacuum port blockage, intake leaks, and wiring continuity.
Inspect for related MAF, boost, throttle, or fuel trim codes that can help separate sensor, wiring, and airflow faults.

Related OBD-II codes

These nearby fuel / air entries can help compare wording and pin down the fault area.