P0109 — Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent
Drive with caution — fix soon.
What P0109 means
This code means the engine computer detected an intermittent fault in the manifold absolute pressure (MAP) sensor circuit, where the signal drops out or jumps now and then rather than constantly. It's usually caused by loose or corroded wiring and connectors, or a sensor starting to fail. Intermittent codes take patience to pin down, but they're often fixable by repairing connections or replacing the sensor.
Common symptoms
- Check engine light comes on and off
- Occasional rough idle or stumble
- Intermittent hesitation when accelerating
- Inconsistent fuel economy
- Brief loss of power that comes and goes
Common causes
- Loose or corroded MAP sensor connector
- Frayed or damaged wiring in the circuit
- Failing MAP sensor
- Poor ground connection
- Loose or cracked vacuum hose
Typical repair cost
$100 – $350
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0109 code?
Usually yes for short trips, but the intermittent signal means performance can drop without warning. You may feel occasional hesitation or stumbling. Get it diagnosed before it becomes constant.
How much does it cost to fix a P0109?
Repairs typically run $100 to $350. A wiring or connector repair is cheaper, while replacing the MAP sensor with labor costs a bit more.
Is a P0109 code serious?
It's moderate. It won't usually cause immediate engine damage, but the on-and-off signal can lead to stalling and poor performance over time, so it's worth addressing.
Why is my P0109 code intermittent?
Intermittent faults usually come from loose or corroded connections that only lose contact under vibration or heat. A mechanic will often wiggle-test the connector and wiring to find the weak spot before replacing parts.