P0109 Code: Manifold Absolute Pressure Sensor Circuit Intermittent
🟠 Moderate severity · drivable
Usually still drivable, but the engine may stall or hesitate when the MAP signal drops out.
What P0109 means
The MAP sensor signal is dropping out or changing suddenly. The computer sees intermittent readings instead of a steady pressure signal. This often comes from a loose connection or damaged wiring.
Symptoms
- Check engine light on
- Intermittent stalling or hesitation
- Rough idle that comes and goes
- Sudden power loss while driving
Common causes
- most common: Loose or corroded MAP connector
- common: Damaged wiring in the harness
- common: Faulty MAP sensor
- less common: Cracked vacuum hose
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Clean and reseat the connector | Yes | $0–20 |
| Repair damaged wiring | Yes | $20–80 |
| Replace the MAP sensor | Yes | $40–120 |
| Replace the vacuum hose | Yes | $5–20 |
Frequently asked questions
Can I drive with P0109?
Usually yes, but the engine may stall or hesitate when the signal drops out. Start by checking the connector.
Why is the code intermittent?
Intermittent means the problem comes and goes. Loose plugs, chafed wires, and failing sensors cause this pattern.
Do I need a new MAP sensor for P0109?
Not always. Check the connector and wiring first because loose connections are a top cause of intermittent faults.
Related codes
P0105
P0105 Code: Manifold Absolute Pressure Sensor Circuit
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P0107P0107 Code: Manifold Absolute Pressure Sensor Circuit Low
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.