Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

The barometric pressure (BARO) sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. This gives the powertrain control module (PCM) an indication the current of barometric pressure. The PCM uses this information to calculate fuel delivery. The BARO sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM supplies 5 volts to the BARO sensor on a 5-volt reference circuit, and provides a ground on a low reference circuit. The BARO sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes. The PCM compares the BARO sensor to the manifold absolute pressure (MAP) sensor in order to monitor the BARO sensor operation. If the difference between the two sensors is more than a predetermined amount, DTC P0069 sets.