P0109
- Powertrain
- Generic (SAE)
- Emissions
Diagnose soon
Usually safe to drive short distances, but the fault will not clear itself and can worsen or fail an emissions test.
Manifold Absolute Pressure / Barometric Pressure Circuit Intermittent
This code is in our catalogue but has not yet been through editorial review, so the guidance below is limited to what our structured data supports. We publish deeper diagnostic content only after a code has been reviewed — here is why.
The ECU detects intermittent signal dropouts on the MAP/BARO sensor circuit. Fault is not constantly present — typically caused by loose connectors, chafed wiring, or a sensor failing under thermal load.
A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.
- Safe to drive
- Usually safe to drive short distances, but the fault will not clear itself and can worsen or fail an emissions test.
- Urgency
- Diagnose soon
- Will it pass emissions
- No
- Check engine light
- Solid
- Clearing the light
- A completed drive cycle is normally required before the monitor re-runs and the light can clear.
| # | Cause | How often | Component |
|---|---|---|---|
| 1 | MAP connector loose or corroded | Very common | — |
| 2 | Sensor fails when hot | Common | — |
| 3 | Wiring chafed or pinched | Common | — |
Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.
- MAP Sensor
- MAP Connector
- MAP Wiring
- Definition
- Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.
- Diagnostic guidance
- Written and reviewed in-house. See our editorial policy.
- Review status
- Awaiting review
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