P0108 code meaning
Manifold Absolute Pressure/Barometric Pressure Sensor Circuit High
Powertrain system Generic code P01xx codes Check engine light
What P0108 means
The manifold absolute pressure (MAP) sensor measures the pressure behind the throttle; on vehicles without a separate barometric sensor it also supplies the ambient pressure, read at key-on or wide-open throttle – hence 'MAP/BARO'. It is a three-wire sensor with 5 V reference, ground and signal. P0108 means the signal voltage is above its upper limit – typically an open ground (low reference), a signal wire shorted to 5 V or battery voltage, or a failed sensor. Like P0107 it describes the voltage, not real overpressure; genuinely excessive boost is P0234. Documented limits: GM gasoline above 86 % of 5 V, GM diesel above 97 %, GM/Saab 2.0T above 4.80 V for 4 s, Ford above 4.88–4.96 V for 5 s. The engine substitutes a modelled value, which often makes the mixture too rich; turbo engines limit boost.
P0108 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1 hours
- Clears after repairAfter a drive cycle
Symptoms of P0108
- Check engine light on
- Rich mixture, sooting, higher consumption
- Rough idle, loss of power or limp mode on turbo engines
Common causes of P0108
- Most likelyGround (low reference) wire open or connector corroded
- PossibleSignal wire shorted to 5 V or battery voltage
- PossibleMAP sensor failed internally
- Less likelyEngine control module faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Manifold absolute pressure sensorSensor wiringSensor reference voltage
What each part of P0108 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 08 | The exact fault in that area. |
What to do next
- Note P0108 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0108
What does P0108 mean?
P0108 means "Manifold Absolute Pressure/Barometric Pressure Sensor Circuit High". The manifold absolute pressure (MAP) sensor measures the pressure behind the throttle; on vehicles without a separate barometric sensor it also supplies the ambient pressure, read at key-on or wide-open throttle – hence 'MAP/BARO'. It is a generic code, so it means the same on every make.
Is it safe to drive with P0108?
Drive gently and only to a workshop. With P0108 the car can go into limp mode (reduced power) to protect itself.
Will P0108 fail an emissions test?
Yes, it can. P0108 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0108 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0108 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.