P0108: OBD-II code P0108 means the MAP sensor is reading impossibly high pressure — usually an open signal circuit or a bad sensor.

Symptoms

• Check engine light is on; engine may run rich as the PCM sees a false high-load signal.
• Rough idle, hesitation, and reduced fuel economy from incorrect fuel metering.
• Black smoke on acceleration due to rich fuelling under mistaken high-load conditions.

Common causes

• A failed MAP sensor with an internally stuck-high signal element.
• An open signal wire between the sensor and the PCM, pulling the signal high.
• A blocked or restricted vacuum reference line to the sensor.

What to do?

Read live MAP kPa with the engine at idle — should be ~30-40 kPa. If stuck high, disconnect the sensor and check if the reading changes. Verify the vacuum port is clear. Replace the sensor if the signal is stuck high with vacuum applied.