Code P031, Shorted Manifold Absolute Pressure (Map) Sensor: Action

WARNING: This page is about a different car, the 1995 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

PCM turns on MIL. PCM sets BARO equal to 92 kPa, and uses a substitute MAP value based on engine RPM and throttle position switch status. PCM disables long term fuel trim.

NOTE: Test numbers refer to numbers on diagnostic chart.

If PCM data PD02 goes to 14-16 kPa with sensor unplugged, sensor or sensor connector is faulty.
Checks for open circuit between MAP sensor terminal "A" and PCM terminal 2A5 (ground). If ground is open, signal voltage will always be high.