A 5-volt reference and ground is supplied to the Barometric Pressure Sensor from the ECM/PCM. A sensor voltage that is proportional to the atmospheric pressure is sent to the ECM/PCM.
Removal & Installation
- Disconnect the negative battery cable.
Replacing the sensor requires disconnecting the electrical connector, then carefully removing the lid of the air filter housing.
NOTEHandle the sensor assembly carefully, protecting it from impact, extremes of temperature and/or exposure to shop chemicals.
- Installation is the reverse of the removal procedure.
- Disconnect the sensor connector and measure at the harness side.
- Turn the ignition switch to the "ON" position.
- Measure the voltage between terminal 1 and ground. Voltage should be between 4.8 and 5.2 volts.
- Turn the ignition switch to the "LOCK" (OFF) position.
- Check for the resistance between terminal 5 and ground. Resistance should be less than 2 ohm.
- If any check above does not meet the specifications, check connectors and wiring between the sensor and ECM/PCM. If ok, replace ECM/PCM.
- If all checks above meet the specifications, disconnect sensor connector and, using a jumper test harness in between, turn the ignition switch to "ON" position and measure the voltage between terminal 2 and ground. Standard value: 3.7-4.3 V at sea level. 3.4-4.0 V at 5,906 ft. 3.2-3.8 V at 3,937 ft. 2.9-3.5 V at 1,969 ft.
- If not within specifications, replace the Mass Air Flow (MAF) Sensor.