With the ignition key Off, remove the electrical connector from the transmission range sensor, ensuring to disconnect it by hand without using tools. Examine the connector socket on the sensor for any loose, corroded, or bent pins using a small mirror. Major testing of the transmission range sensor and harness typically requires a scan tool, but basic continuity can be checked between some terminals on the sensor with an ohmmeter or continuity tester. Check for continuity between the indicated terminals at the sensor with the connector disconnected: there should be continuity between terminals 1 and 4 in Park or Neutral, between terminals 5 and 8 in Neutral, and between terminals 2 and 3 in Reverse. If any tests fail, replace the transmission range sensor, and further testing should be performed with a scan tool. To replace the sensor, disconnect the negative cable from the battery, shift the transmission into Neutral, and securely raise the front of the vehicle on jack stands, ensuring the air suspension switch is turned OFF if equipped with Automatic Ride Control. Remove the
Shift Cable from the shift lever and cable bracket, make a mark on the transmission shift lever relative to its position in Neutral, then remove the nut and take off the shift lever. Disconnect the electrical connector from the transmission range sensor, remove the bolts, and detach the sensor. Before installing the new sensor, ensure the transmission is in Neutral, align the flats on the switch with the flats in the shaft, and position the sensor onto the shaft. Install the bolts finger-tight; precise adjustment requires a special tool, but if unavailable, connect the electrical sensor, reconnect the negative battery cable, turn the ignition key On, shift into Reverse, rotate the sensor until the back-up lights come on, and then tighten the mounting bolts. The remainder of the installation follows the reverse order of removal, using a new nut for the shift lever. Finally, apply the parking brake and verify that the engine starts only in Neutral or Park.