Common causes include: Corroded MAP/BARO connector; Intermittent wire break or short; Failing pressure sensor.

P0109: Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent

Q: What does code P0109 mean?

P0109 is the generic OBD-II code for 'Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent'. The MAP or barometric pressure input is interrupted or inconsistent. The fault may only occur when the harness moves or the sensor warms up, leaving a plausible reading when the vehicle is later scanned.

Severity: Medium Drive gently and get it diagnosed soon.

What does P0109 mean?

The MAP or barometric pressure input is interrupted or inconsistent. The fault may only occur when the harness moves or the sensor warms up, leaving a plausible reading when the vehicle is later scanned.

Generic OBD-II definition: Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent. Confirm applicability in your vehicle service information.

Common causes

Corroded MAP/BARO connector
Intermittent wire break or short
Failing pressure sensor

Symptoms

Intermittent hesitation
Unsteady idle
Check engine light

Diagnostic focus

Look for sudden steps in pressure data that do not match throttle movement. An abrupt electronic dropout is different from a gradual real change in manifold vacuum.

Can I keep driving with P0109?

Severity: Medium Drive gently and get it diagnosed soon.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

Record MAP and BARO data with freeze-frame conditions
Inspect terminal grip and wiring near the sensor
Repair intermittent contact and verify a smooth pressure response

Sources & review

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.