Code Definition

P1108 — Manifold Absolute Pressure Sensor circuit high input

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Honda

About P1108

P1108 is a manufacturer-specific powertrain diagnostic trouble code recorded for Honda vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1108 is stored, the module has detected a signal or supply voltage higher than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1108 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Manifold Absolute Pressure (MAP) sensor supplies the Engine Control Module (ECM) with a variable voltage that represents intake manifold pressure, which the ECM uses to calculate engine load and adjust fuel delivery and ignition timing. DTC P1108 sets when the ECM detects the MAP signal voltage staying higher than the expected range, typically approaching the 5V reference, which usually indicates a short to voltage, an open sensor ground, or an internally failed sensor rather than a genuine pressure reading. Because the ECM can no longer trust the load signal it may substitute a default va...

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