Barometric Pressure Sensor (BARO)
The Barometric Pressure Sensor (BARO) is used to directly measure barometric pressure and for exhaust back pressure estimation. (Exhaust back pressure influences speed density based air charge computation.) The BARO sensor is directly mounted to the PCM circuit board.
The BARO sensor has a high accuracy operating range of 60 to 115 kPa (17.7 to 34.0 "Hg) and a full operating range of 7.6 to 121.6 kPa. The voltage is electrically clipped between 0.3 and 4.8 volts.
A P2228 or P2229 DTC indicates that either the sensor is electrically faulted or the sensed barometric pressure is outside the normal operating range.
BARO SENSOR TRANSFER FUNCTION
| Vout=Vref * (0.007895 * Pressure (in kPa) | ||
| Volts | Pressure, kPa | Pressure, Inches Hg |
| 0.3 | 7.6 | 2.2 |
| 0.5 | 12.7 | 3.8 |
| 2.638 | 60 | 17.7 |
| 4.54 | 115 | 34.0 |
| 4.75 | 120.3 | 35.5 |
| 4.8 | 121.6 | 35.9 |
BAROMETRIC PRESSURE SENSOR RANGE CHECK
| DTCs | P2228 Barometric Pressure Circuit Low P2229 Barometric Pressure Circuit High |
| Monitor execution | continuous |
| Monitor Sequence | None |
| Sensors OK | not applicable |
| Monitoring Duration | 5 seconds to register a malfunction |
TYPICAL BAROMETRIC PRESSURE SENSOR RANGE CHECK MALFUNCTION THRESHOLDS
| P2228 BP < 2.0 volts (above 15, 000 ft altitude) P2229 BP > 4.4 volts (below -1, 000 ft altitude) |