Fault codeP0108

MODERATE

Manifold Absolute Pressure/Barometric Pressure Circuit High Input

What this code means

Manifold Absolute Pressure/Barometric Pressure Circuit High Input.

P0108 is a generic code: it means the same thing on every make. P0108 belongs to family P01xx — Fuel and air metering. Its page explains how to read a code and groups all its codes by part.

Type of fault

The control unit reads a voltage on this circuit above its expected range. Usual causes: a broken wire or a poor ground, a short to a supply voltage, or the component itself. As with a low signal, check the wiring and connector before the part.

Manifold pressure sensor (MAP)

The MAP sensor measures the pressure, or vacuum, inside the intake manifold. On many engines it is the main measure of engine load; on others it supplements the airflow sensor. It is often combined with the barometric pressure reading used to correct for altitude.

What you notice

Hesitation, poor acceleration, rough idle, higher consumption, and black smoke on diesels.

How to check it

Check the sensor's vacuum hose if it has one (split, disconnected or full of oil), its connector, and the intake for leaks. Engine off, the manifold pressure and the barometric pressure should be almost the same; at idle on a petrol engine the manifold pressure should drop to roughly 30 kPa. Klaro shows both.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Intake manifold pressure
Barometric pressure
Mass air flow

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
1Fuel and air metering
08P0108