P0108 on Honda: How to Diagnose & Fix
Manifold Absolute Pressure/Barometric Pressure Circuit High Input
1 Honda model · 1 documented issue · $40-$180 repair
P0108 on Honda by model: symptoms, diagnosis and fix
The manifold absolute pressure (MAP) sensor mounted on the throttle body of 1.6L D16 Civics commonly fails as it ages, losing the ability to hold vacuum or drifting out of its 0.5-4.5V calibration range. Because the PCM uses MAP voltage as the primary load input on these speed-density systems, a failing sensor causes the ECU to mis-fuel and mis-time the engine. Failures often set P0107 / P0108 / P1128 / P1129 codes and frequently coincide with cracked vacuum hoses on the upper intake.
Common Symptoms
- Check engine light with P0107, P0108, P1128 or P1129
- Rough idle and stumbling
- Hesitation and loss of power under load
- Rich-running condition and rotten-egg smell from catalyst
- Hard cold starts and emissions test failure
How to Fix
Verify the vacuum supply hose at the throttle body is not cracked or off, then back-probe the MAP sensor signal wire: at key-on engine-off it should read ~2.8-3.0V (atmospheric), dropping to ~1.0-1.5V at idle. If voltage is stuck high, stuck low, or doesn't track manifold vacuum, replace the MAP sensor (Honda P/N 37830-P05-A01 or equivalent). Clear codes and re-test; persistent codes after replacement usually indicate a vacuum leak.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Honda 37830-PAA-S00 MAP sensor setOEMHonda 37830-PAA-S00 (replaces 37830-P0G-S00)
MAP sensor replacement after reference, ground, vacuum passage and signal-response tests prove sensor failure Fitment/availability: Honda catalog fitment covers 1996-2000 Civic DX/EX/HX/Si/CX/GX/LX branches and supersedes 37830-P0G-S00. …
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Sources for this issue (3)
P0108 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0108 mean on a Honda?
P0108 stands for "Manifold Absolute Pressure/Barometric Pressure Circuit High Input." The PCM detects an abnormally high voltage signal from the MAP/BARO sensor circuit, above the expected range for the engine's operating condition. It often means the sensor reports high manifold pressure when the PCM expects low pressure (such as at idle). Symptoms include reduced fuel economy, poor performance, rough running, and an illuminated check engine light. On Honda it is documented across 1 model: Civic.
What are the most common causes of P0108?
The most common causes of P0108 are: Faulty MAP/BARO sensor, Short to voltage in the MAP signal circuit, Disconnected or leaking vacuum supply to the sensor, Wiring or connector damage at the sensor, Restricted exhaust or clogged catalytic converter raising manifold pressure, Failed PCM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0108 on a Honda?
Published repair estimates on Honda range from $40 to $180 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0108 on a different make?
View P0108 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.