OBD-II Trouble Code Technical Description
Manifold Absolute Pressure – Barometric Pressure Correlation
What does that mean?
This generic powertrain/engine diagnostic trouble code typically applies to all OBDII equipped engines, but shows up more often in certain Audi, Ford, Mazda, Mitsubishi, Saturn and VW vehicles.
The Manifold Absolute Pressure (MAP) sensor converts engine vacuum into an electrical signal for the Powertrain Control Module (PCM). The engine may also have a Barometric Pressure (BARO or just BP) sensor to convert atmospheric pressure into an electrical signal to the PCM
The PCM receives these inputs and possibly two more; Mass Airflow (MAF) and Throttle Position Sensor (TPS) to determine load and altitude. The PCM looks at the MAP sensor voltage and compares it to the BARO sensor reading when the ignition switch is first turned on. This code is set if these inputs vary too much.