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DTC P031: Shorted Map Sensor: Action

  1. PCM turns on the "SERVICE ENGINE SOON" MIL.
  2. PCM disables long term fuel trim.
  3. PCM uses a substitute MAP value based on engine RPM and throttle position switch status.
  4. PCM disables evaporative emission control solenoid.
  5. PCM disables torque management.
  6. Transaxle shift adapts are maintained at current levels.
NOTE: Numbers in list refer to circled numbers in diagnostic flow chart, see Fig 1. For circuit identification see Fig 2.
  1. If Code P038 is also set, CKT 469 or 455 is open or shorted to voltage because MAP sensor and IAT sensor share the same return.
  2. If MAP sensor or circuitry are shorted, PD02 will read 103-105 kPa.
  3. If PCM data PD02 goes to 10-16 kPa with the C102 unplugged, the fault is in the sensor or wiring from C102 (intake manifold side) to MAP sensor.
  4. Checking CKT 432 for a short to battery. If wire OK, replace the PCM.
Fig 1: DTC P031: Shorted MAP Sensor Flow Chart
G00118435Courtesy of GENERAL MOTORS CORP.
Fig 2: DTC P031: Shorted MAP Sensor Flow Chart Circuit
G00121802Courtesy of GENERAL MOTORS CORP.