P0108: MAP / Barometric Pressure Circuit High Input
TL;DR
P0108 = MAP/BARO circuit high input. Severity: medium. Top causes: faulty MAP sensor (35%), restricted/blocked vacuum hose (25%), wiring short to voltage (25%), connector fault (15%).
Can I keep driving with P0108?
IF it runs acceptably → drive briefly to diagnose; check the vacuum hose for blockage. IF it runs very rich, hesitates or is in limp mode → drive minimally, since fueling is based on a bad load signal.
Symptoms
- Check engine light on
- Rich running or black smoke
- Reduced power
- Rough idle
- Worse fuel economy
Top causes (ranked by probability)
| Likely cause | Probability | Notes |
|---|---|---|
| Faulty MAP sensor | 35% | |
| Restricted or blocked vacuum hose/port | 25% | |
| Signal wire short to voltage | 25% | |
| Connector fault | 15% |
What does P0108 mean?
Technical explanation
P0108 sets when the MAP signal voltage stays above the expected range. Causes include a failed sensor, a signal-wire short to voltage, or a restricted/blocked MAP vacuum supply that makes the sensor read implausibly high pressure. Because the ECM uses MAP to estimate load, a high signal causes incorrect fueling — typically rich, with poor performance and worse economy.
In simple terms
The MAP sensor measures intake pressure so the computer can fuel the engine correctly. P0108 means it’s reading too high — often a blocked vacuum hose, a wiring fault, or a bad sensor. The car may run rich, lack power and use more fuel.
How to diagnose P0108 (step by step)
- Read MAP live data. A reading stuck high (with high voltage) confirms it.
- Check the MAP vacuum hose/port. A restricted or blocked supply makes the sensor read high.
- Check wiring for a short to voltage. A signal wire shorted to power pulls the reading high.
- Inspect the connector. Look for corrosion or damage.
- Replace the MAP sensor if faulty. If wiring and vacuum are good, replace the sensor.
Repair options & cost
- Replace the MAP sensor
- Clear/replace the vacuum hose or port
- Repair the wiring short
- Repair the connector
🔧 Doing it yourself? Buy the part: MAP (manifold pressure) sensor
| DIY cost | $15–$120 |
|---|---|
| Workshop cost | $90–$350 |
| Repair time | 20–60 minutes |
Costs are local ballpark ranges and vary by region and vehicle.
Tools you’ll need
Scan your car: recommended OBD-II scanners →Vehicle-specific notes
- Check the MAP vacuum hose/port for blockage before replacing the sensor.
- P0108 (high) is the opposite of P0107 (low).
- A short to voltage in the signal wire is a common electrical cause.
Common mistakes to avoid
- Replacing the sensor while the vacuum port is blocked
- Missing a signal-wire short to voltage
- Overlooking a corroded connector
- Not comparing live MAP data to expected values
Frequently asked questions
What causes a P0108 code?
A faulty MAP sensor, a restricted/blocked vacuum hose or port, a signal-wire short to voltage, or a bad connector. Check the vacuum supply before replacing the sensor.
Is P0108 the same as P0107?
They’re opposites: P0108 is a high MAP signal, P0107 is a low one. Both point to the MAP sensor, its wiring, or the vacuum supply.
Can I drive with P0108?
Short-term if it runs acceptably, but expect rich running and worse economy. If it hesitates badly or is in limp mode, drive minimally and fix it.
P0108 summary
| Meaning | MAP/BARO circuit high input |
|---|---|
| Severity | Medium |
| Safe to drive? | Caution — may run rich |
| Top cause | Faulty MAP / blocked hose (60%) |
| DIY cost | $15–$120 |
| Shop cost | $90–$350 |