What Does the P0108 Code Mean?
The P0108 diagnostic trouble code stands for “Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage.”
It’s triggered when the MAP sensor sends a higher-than-expected signal to the engine control module (ECM). In some vehicles, the MAP sensor also functions as a barometric pressure (BARO) sensor, so this code may apply to both systems if they share the same circuit.
NOTE: A BARO sensor measures atmospheric pressure to help the engine control module adjust fuel delivery and ignition timing based on altitude and weather conditions.
But what does the MAP sensor do?
The MAP sensor measures pressure inside the intake manifold and helps the ECM calculate the right air-fuel mixture. Along with data from sensors like engine speed, air temperature, and the MAF sensor, it ensures efficient combustion by telling the ECM how much air enters the engine.
The ECM also compares this information with input from the throttle position sensor (TPS) to determine engine load and adjust fuel delivery accordingly.
The P0108 code occurs when the sensor voltage remains above normal range for too long, typically over 4.5 volts. This high-voltage reading can disrupt how the ECM manages fuel delivery and engine performance.