P0109
Generic (SAE) Basic entry
Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent
Severity
Medium
Typical repair cost
40 – 350 EUR
System
Powertrain
What it means
P0109 is stored when the Manifold Absolute Pressure/Barometric Pressure signal drops out or jumps erratically for short periods. Intermittent faults are almost always connector, wiring or vibration related.
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Symptoms
- Check engine light on
- Rough or unstable idle
- Hesitation or poor acceleration
- Increased fuel consumption
- Possible limp mode with reduced power
Common causes
- Damaged, chafed or corroded wiring in the Manifold Absolute Pressure/Barometric Pressure circuit
- Corroded, loose or water-damaged connector terminals
- Failed Manifold Absolute Pressure/Barometric Pressure component (sensor, solenoid or actuator)
- Poor ground connection for the module or component
- Faulty control module driver (rare, confirm all else first)
How to diagnose
- Read freeze frame data and note when the code set (cold start, under load, after rain)
- Inspect the Manifold Absolute Pressure/Barometric Pressure connector for bent pins, corrosion and water; wiggle the harness with the engine running and watch live data
- Measure supply voltage and ground at the connector with the key on
- Check the signal wire for shorts to ground or battery and for continuity to the control module
- Test or substitute the Manifold Absolute Pressure/Barometric Pressure only after wiring and connectors are confirmed good
- Clear the code and complete a drive cycle to confirm the repair
Frequently asked questions
Can I keep driving with P0109?
Usually yes for a short time, but expect reduced performance or higher fuel use. Have it diagnosed within a few days.
Will clearing P0109 fix it?
No. Clearing only erases the stored code; it returns as soon as the monitor runs again unless the cause is repaired.
Related codes
Nearby codes in this group
- P0108Manifold Absolute Pressure / Barometric Pressure Circuit High Input
- P0110Intake Air Temperature Sensor 1 Circuit (Bank 1)
- P0107Manifold Absolute Pressure / Barometric Pressure Circuit Low Input
- P0111Intake Air Temperature Sensor 1 Circuit Range/Performance (Bank 1)
- P0106Manifold Absolute Pressure / Barometric Pressure Circuit Range/Performance
- P0112Intake Air Temperature Sensor 1 Circuit Low (Bank 1)
- P0105Manifold Absolute Pressure / Barometric Pressure Circuit
- P0113Intake Air Temperature Sensor 1 Circuit High (Bank 1)