Generic OBD2 code · Fuel and air metering

P0108: Manifold Absolute Pressure/Barometric Pressure Circuit High

The engine computer saw the manifold absolute pressure (MAP) or barometric pressure sensor signal voltage stay above its normal range.

CodeP0108

SystemFuel and air metering

Typical urgencyModerate to high

Can I keep driving?Often drivable, but performance and fuel economy can suffer. Diagnose it soon.

What does P0108 mean?

The MAP sensor signal rises as manifold vacuum falls. At idle the engine has strong vacuum and the signal is low; at wide open throttle it is high. P0108 sets when the signal stays higher than the computer considers normal for the operating conditions.

Both references list vacuum leaks alongside the sensor and its wiring. A leak reduces manifold vacuum, which makes the reading higher, so hoses deserve a check before parts are replaced.

Common symptoms

Check engine light on
Hard starting or poor running
Lower fuel economy
Poor engine performance

Common causes

The causes below are the ones commonly seen with P0108. The actual cause can vary by vehicle, engine and mileage, so treat this list as a starting point, not a diagnosis.

A faulty MAP or barometric pressure sensor
An engine vacuum leak or a leaking vacuum line to the sensor
Faulty, shorted or corroded wiring or connectors in the sensor circuit

What to check with a scanner

With the key on and engine off, compare the MAP reading with barometric pressure. Then start the engine: the reading should drop clearly at warm idle.
Check the vacuum hose to the MAP sensor, if fitted, and other intake hoses for cracks.
Look at short and long term fuel trims for signs of a lean condition from a leak.
Inspect the connector and harness for damage.

How to read and clear P0108 with OBD Master Pro

Plug in your adapter. Connect a generic ELM327 (or ELM329) OBD2 adapter to the diagnostic port, usually under the dashboard on the driver's side. Bluetooth Classic, Bluetooth LE, Wi-Fi and USB OTG adapters are supported.
Switch the ignition on. Turn the key to ON or start the engine, depending on your car.
Connect in OBD Master Pro. Open the app, go to Connection and pick your adapter. Classic Bluetooth adapters connect from the Bluetooth tab, Bluetooth LE adapters from the BLE tab with no pairing needed. Use the generic OBD2 / EOBD profile or your car's brand profile.
Read the codes. Open the fault codes screen to see stored, pending and permanent codes. Confirm P0108 is listed and note any other codes, since they often explain the cause.
Check the details. Look at freeze frame data, Live data and, where your car supports it, Mode 06 test results (see the checks above).
Fix, then clear. After the repair, clear the codes to turn off the check engine light. Clearing also resets the emissions readiness monitors, so drive normally and check the readiness screen before any inspection. Permanent codes cannot be erased with a scan tool; they clear on their own once the car's self test passes.

Tip: you can also look up P0108 and other codes in the app's DTC search without connecting to a car. If your adapter will not connect, use Connection > Share connection log and email it to support. Many cheap ELM327 clones only handle basic engine OBD2, which is all you need for P0108.

When to see a mechanic

Get professional help if any of these apply:

You cannot find a leak and need a smoke test
The engine runs poorly or stalls
The code returns after the sensor was replaced

If you are unsure, a qualified technician can confirm the cause with tests such as smoke testing, pressure testing or scope readings. Clearing a code does not repair the fault.

P0108 FAQ

Can a vacuum leak cause P0108?

Yes. A leak lowers manifold vacuum, so the MAP reading rises. RepairPal also lists replacing the sensor when the real cause was a vacuum leak as a common misdiagnosis.

Is P0108 serious?

It is usually not dangerous, but the engine may run poorly and use more fuel. Diagnose it soon.

What should the MAP reading be with the engine off?

With the engine off there is no vacuum, so the MAP reading should be close to the barometric pressure reading.

Check P0108 on your own car

OBD Master Pro turns your Android phone and a generic ELM327 adapter into a code reader: read and clear codes, view freeze frame and live data, and check emissions readiness.

Sources

Published October 24, 2026. Updated October 24, 2026. This guide is general information for generic SAE codes. Always follow the service information for your specific vehicle.