Note On Intermittents

Manipulate MAP sensor connector, wiring and PCM connector while observing PCM data PD02. Apply and release vacuum to MAP sensor vacuum port. If PCM data PD02 immediately jumps to greater than 108 kPa, repair intermittent MAP sensor fault. If wiring and connectors are okay, substitute a known good MAP sensor and retest.

Fig 1: Code P031 Schematic, Shorted MAP Sensor

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P031 Diagnostic Flow Chart, Shorted MAP Sensor

Courtesy of GENERAL MOTORS CORP.