When the 2023 Chevrolet Equinox sets P0108, the MAP sensor is sending higher voltage than the ECU expects for current conditions. High MAP readings indicate low vacuum or positive pressure, causing the engine to deliver excess fuel based on perceived high load.
Understanding P0108
P0108 indicates MAP sensor voltage exceeds expected thresholds. While readings approach maximum during wide-open throttle, they should drop significantly at idle when manifold vacuum is highest. If readings remain high regardless of conditions, P0108 sets.
Equinox Engine and MAP Function
The 2023 Equinox uses a 1.5L turbocharged engine. The MAP sensor monitors manifold pressure under both vacuum (deceleration, idle) and boost (acceleration) conditions. High constant readings cause the ECU to think the engine is always under load, resulting in rich running and poor fuel economy.
Common Causes of High MAP Readings
Vacuum leaks cause low manifold vacuum, which the MAP sensor accurately reports as high pressure. The sensor may be working correctly, but an intake leak prevents proper vacuum development. Check all vacuum hoses and intake connections.
A shorted signal wire can cause artificially high readings. If the signal wire contacts a voltage source, readings will be high regardless of actual pressure.
A failed MAP sensor outputting high voltage causes P0108. Internal sensor failure can lock output at maximum regardless of actual conditions.
Diagnostic Approach
Monitor MAP readings at idle—should show significant vacuum (low pressure/low voltage). If readings are high at idle, check for vacuum leaks first. With engine off, MAP should read atmospheric pressure. Check for wiring shorts by disconnecting the sensor and measuring circuit voltage.