Faulty atmospheric pressure sensor, which is typically part of the MAF or MAP sensor assembly.; Contaminated or damaged MAF sensor element affecting the integrated pressure sensor.; Wiring issues such as open circuits, short circuits, or high resistance in the sensor signal or ground circuits.; Corroded or loose electrical connectors at the sensor or ECM.; A restricted or blocked sensor port, such as a clogged MAF sensor screen or a blocked pressure sensor passage.; ECM software glitch or internal fault, though this is less common.; Extreme altitude changes without ECM recalibration, though the ECM should adapt automatically.

DTC codes / Subaru codes / P1112

P1112 · SubaruAtmospheric Pressure Sensor Range Performance Problem

Q: What does code P1112 mean?

Atmospheric Pressure Sensor Range Performance Problem. P1112 on a Subaru indicates that the engine control module (ECM) has detected an implausible or out-of-range signal from the atmospheric pressure sensor, which is often integrated into the mass airflow (MAF) sensor or the manifold absolute pressure (MAP) sensor. The ECM compares this reading with other sensor inputs, such as manifold pressure and throttle position, and sets the code when the atmospheric pressure value does not match expected values for the current operating conditions.

P1112 on a Subaru indicates that the engine control module (ECM) has detected an implausible or out-of-range signal from the atmospheric pressure sensor, which is often integrated into the mass airflow (MAF) sensor or the manifold absolute pressure (MAP) sensor. The ECM compares this reading with other sensor inputs, such as manifold pressure and throttle position, and sets the code when the atmospheric pressure value does not match expected values for the current operating conditions.

SystemPowertrain

Code typeSubaru specific

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms.
Rough idle or stumbling, especially when the engine is cold or at high altitude.
Reduced engine performance or hesitation during acceleration.
Poor fuel economy due to incorrect air-fuel mixture calculations.
In rare cases, the engine may stall or have difficulty starting.

Common causes, most likely first

Faulty atmospheric pressure sensor, which is typically part of the MAF or MAP sensor assembly.
Contaminated or damaged MAF sensor element affecting the integrated pressure sensor.
Wiring issues such as open circuits, short circuits, or high resistance in the sensor signal or ground circuits.
Corroded or loose electrical connectors at the sensor or ECM.
A restricted or blocked sensor port, such as a clogged MAF sensor screen or a blocked pressure sensor passage.
ECM software glitch or internal fault, though this is less common.
Extreme altitude changes without ECM recalibration, though the ECM should adapt automatically.

How to diagnose and fix it

Use an OBD-II scanner to verify the code and check for any related pending or stored codes.
Inspect the MAF or MAP sensor connector and wiring for damage, corrosion, or loose pins; repair as needed.
Check the sensor's physical condition, looking for contamination or blockage, and clean the MAF sensor with a dedicated cleaner if applicable.
Compare the atmospheric pressure reading (often displayed as barometric pressure) with a known good value from a barometer or another vehicle at the same altitude.
Perform a voltage drop test on the sensor's power and ground circuits to ensure they are within specification.
If the sensor is integrated into the MAF, test the MAF sensor's output signal and replace the assembly if faulty.
After repairs, clear the code and perform a road test to confirm the fix, ensuring the monitor runs and the code does not return.

Atmospheric Pressure Sensor Pitfalls on Subaru

The atmospheric pressure sensor is often integrated into the MAF sensor on many Subaru models, so a faulty MAF can set P1112 even if the pressure-sensing portion seems fine.
A dirty or contaminated MAF sensor can cause incorrect atmospheric pressure readings, so cleaning the sensor before replacement can save time and money.
Wiring problems, such as a chafed harness near the intake or a corroded ground, are common causes that are frequently overlooked in favor of sensor replacement.
Altitude changes can temporarily affect atmospheric pressure readings, but the ECM should adapt; persistent codes after driving at different altitudes may indicate a sensor that is slow to respond.
Do not confuse P1112 with manifold absolute pressure (MAP) sensor codes; on Subaru, P1112 specifically refers to the atmospheric pressure sensor, which may be a separate sensor or part of the MAF.

Can I keep driving with P1112?

The vehicle is generally safe to drive with P1112 because the ECM uses default values if the atmospheric pressure signal is implausible, but you may experience reduced performance or fuel economy. Avoid sustained high-speed driving or heavy loads until the issue is diagnosed, and have the code checked promptly to prevent potential long-term effects.

Tools that help

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Guidance is general and written for Subaru vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.