Pressure Sensor

This sensor is a combination MAP and BARO sensor used on 5.0L (VIN Y) engines. When ignition is first turned on, ECM records sensor input as a barometric pressure reading. After vehicle starts, signal is processed as a MAP sensor input. ECM then internally converts the MAP sensor signal to a vacuum signal by comparing current input to the BARO input stored in memory. Thus, if a "scan" tester is used to measure pressure sensor voltage, reading will differ from that obtained with a DVOM at the sensor. This input is used primarily as an indication of engine load and is utilized by ECM for timing and fuel control calculations. Pressure sensor circuit problems should set Code 34. If Code 34 is not present and pressure sensor is suspected of being the cause of driveability problems, see 5.0L FULL FUNCTION CHART C1D for further diagnosis.