P0108
Manifold Absolute Pressure Sensor Circuit High
The engine computer is seeing a pressure sensor signal that is too high. This usually means a bad MAP sensor, a wiring problem, or a vacuum/boost issue. It can cause rough running, poor fuel economy, and hard starting.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20–$120
- SHOP
- $120–$500
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Faulty MAP sensor
- Open, shorted, corroded, or loose MAP sensor wiring or connector
- Damaged sensor reference voltage or ground circuit
Typical repair cost
DIY usually runs $20–$120. Typical shop repair lands around $120–$500, depending on the root cause.
01 / Definition
P0108 means the powertrain control module has detected a MAP or barometric pressure sensor signal that is above the expected range. On many vehicles this is a high-voltage signal caused by an open circuit, short to voltage, failed sensor, or incorrect pressure reading. The code can also appear if the engine has a major vacuum leak, incorrect boost pressure, or a wiring/connector fault.
02 / Drive status
With caution. You may be able to drive short distances, but the engine can run very rich or very poorly. If the vehicle runs rough, stalls, or has reduced power, do not keep driving it.
03 / Symptoms
- Check Engine Light
- Rough idle
- Hard starting
- Stalling
- Poor acceleration
- Poor fuel economy
- Black smoke from exhaust on some vehicles
- Engine running rich
- Transmission shifting problems on some vehicles
04 / Causes
| 1 | Faulty MAP sensor | high |
|---|---|---|
| 2 | Open, shorted, corroded, or loose MAP sensor wiring or connector | high |
| 3 | Damaged sensor reference voltage or ground circuit | medium |
| 4 | Intake manifold vacuum leak or disconnected vacuum hose | medium |
| 5 | Turbo/supercharger overboost or pressure control problem on boosted engines | medium |
| 6 | Faulty PCM or software issue | low |
| 7 | Incorrect sensor installed or contaminated sensor port | low |
05 / Diagnostic sequence
- 01Check for other codes first, especially throttle, boost, vacuum, or sensor power and ground codes.
- 02Inspect the MAP sensor connector and wiring for loose pins, corrosion, broken wires, oil contamination, or heat damage.
- 03Verify the sensor is receiving the correct 5-volt reference and a good ground with a multimeter.
- 04Check MAP sensor signal voltage with key on engine off and compare it to the service specifications.
- 05Inspect the intake manifold, vacuum lines, and boost hoses for leaks, cracks, or disconnections.
- 06On turbocharged engines, check for overboost, stuck wastegate, or boost control solenoid problems.
- 07If wiring and engine condition are good, test the MAP sensor against specifications or substitute a known-good sensor.
- 08Clear the code and road test while watching live MAP data to confirm the repair.
06 / Repairs
| 1 | Repair or replace damaged MAP sensor wiring, terminals, or connector | $20–$150 |
|---|---|---|
| 2 | Replace the MAP sensor if it fails electrical or live-data testing | $30–$200 |
| 3 | Fix vacuum leaks, cracked intake hoses, or disconnected lines | $10–$200 |
| 4 | Repair turbo boost control faults or overboost conditions if equipped | $100–$600 |
| 5 | Update or replace the PCM only after all sensor and wiring tests pass | $200–$1000 |
07 / Related codes
08 / FAQ
Can a bad MAP sensor cause hard starting?
Yes. A bad MAP signal can make the engine too rich or too lean, which can cause hard starting and rough idle.
Is P0108 usually a sensor or wiring problem?
Most of the time it is a sensor fault, connector issue, or wiring problem. Vacuum or boost problems can also cause it.
Will cleaning the MAP sensor fix P0108?
Sometimes. If the sensor port is dirty or oily, cleaning may help, but a sensor with an electrical fault usually needs replacement.
Can I clear P0108 and keep driving?
You can clear it for testing, but if the problem is still present the code will return. If the engine runs poorly, fix it before driving far.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.