P0109: Manifold absolute pressure (MAP) sensor circuit intermittent
The manifold pressure sensor signal drops out or jumps from time to time. It is almost always a loose connector or a wire with a poor contact.
| Code | P0109 |
|---|---|
| System | Engine and transmission |
| Group | P01xx, Air and fuel metering |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0109 means
The ECU has seen the MAP sensor signal come and go, or change suddenly for no reason. Intermittent faults are usually contact problems: they show up over bumps, with engine heat or in damp weather, and disappear once the car is at the garage.
Most common causes
- Loose MAP sensor connector or spread pins
- Corrosion or moisture inside the connector
- A wire broken inside its insulation making contact on and off
- Vacuum hose that comes loose or kinks now and then
- The sensor itself with an intermittent internal fault
Symptoms
- Jerking or brief loss of power
- Idle speed rising and falling
- Engine warning light coming and going
- Occasional stalling
Can you drive with P0109?
With care You can drive, but sudden power loss could catch you out when overtaking. Have it checked soon.
How to check it
With the engine idling and manifold pressure on screen, gently wiggle the sensor connector, wiring and vacuum hose. If the reading jumps as you move them, you have found the fault.
How to read and clear P0109 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0109 with this same explanation and whether it’s confirmed, pending or permanent.
With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.
Similar codes
- P0105 Manifold absolute pressure (MAP) sensor circuit fault
- P0106 Manifold absolute pressure (MAP) sensor range or performance
- P0107 Manifold absolute pressure (MAP) sensor circuit low
- P0108 Manifold absolute pressure (MAP) sensor circuit high
- P0110 Intake air temperature sensor circuit fault
- P0111 Intake air temperature sensor range or performance
- P0112 Intake air temperature sensor circuit low
- P0113 Intake air temperature sensor circuit high
- P0100 Mass or volume air flow sensor circuit fault
- P0101 Air flow sensor range or performance problem
- P0102 Air flow sensor circuit low input
- P0103 Air flow sensor circuit high input
P0109 is a generic code, so it means the same on any make, for example on Audi, Fiat, Kia, Mazda, Opel / Vauxhall, Toyota. See what Final OBD does on your car in makes and models.
What does code P0109 mean?
The ECU has seen the MAP sensor signal come and go, or change suddenly for no reason. Intermittent faults are usually contact problems: they show up over bumps, with engine heat or in damp weather, and disappear once the car is at the garage.
Can you drive with P0109?
You can drive, but sudden power loss could catch you out when overtaking. Have it checked soon.
How do you clear P0109?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0109 comes back.
Read it on your car
Final OBD reads the faults of every control unit for free, including each make’s own codes, and with Pro explains each one in plain English. Free clears engine faults at no cost.
Coming soon
Mid to late October 2026
If you want to try it in your car before anyone else, send us your email and we will add you as a tester.
info@finalobd.com