1999 was Cadillac's premier year for the Escalade, primarily in response to several German import SUV's and the introduction of the Lincoln Navigator in 1998. The 1999 Escalade was identical to the GMC Denali and remained so until 2002, when the luxury SUV was redesigned. The 1999 model was equipped with a 5.7L vortex engine and included a selectable 4WD drive-train. The manifold absolute pressure sensor converts the difference of atmospheric pressure and intake manifold vacuum into a voltage signal to the powertrain control module.
Things you will need
3/8-inch 3-inch extension
3/8-inch socket set
New MAP sensor
Turn off the engine and remove the key from the ignition. Unscrew the hold-down bolt for the engine cover and remove the engine cover. Locate the MAP sensor on the top rear of the upper intake manifold, on the passenger side.
Disconnect the electrical connector to the MAP sensor. Inspect the connector for any sign of bent or broken pins. Inspect the connector grommet's condition. Remove the MAP sensor by pulling it straight up with a slight twist back and forth. Insure the rubber grommet comes off with the sensor.
Coat the sensor seal with a small amount of oil to help the sensor slide into the intake manifold. Insert the MAP sensor into the intake manifold with steady downward pressure until the sensor seats into position. Connect the electrical connector and replace the upper engine cover using the ratchet, extension, and socket set. Using a code reader, clear the PCM codes. Start the vehicle and run it to operating temperature. Test drive it to ensure the "service engine soon" lamp does not illuminate.