Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, record and erase DTCs
2. Turn the ignition off.
3. Turn the ignition on.
4. Operate the Transfer Case Selector Switch in all positions several times.
5. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension and repair as necessary. If no problems are found, test complete.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE - BODY VERIFICATION TEST .
CHECK THE (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Instrument Cluster C3 harness connector.
3. Disconnect the Transfer Case Selector Switch harness connector.
4. Turn the ignition on.
5. Measure the voltage of the (K77) Transfer Case Position Sensor Input circuit at the Transfer Case Selector Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the (K77) Transfer Case Position Sensor Input circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE - BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Measure the resistance of the (K77) Transfer Case Position Sensor Input circuit between the Transfer Case Selector Switch harness connector and the Instrument Cluster C3 harness connector.
  Is the resistance below 1.0 Ohm?
  
  Yes
  - Go To 4
  No
  - Repair the (K77) Transfer Case Position Sensor Input circuit for an open or high resistance.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE - BODY VERIFICATION TEST .
TRANSFER CASE SELECTOR SWITCH
1. Replace the Transfer Case Selector Switch in accordance with the Service Information.
2. Connect the Instrument Cluster C3 harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Turn the ignition off.
6. Turn the ignition on.
7. Operate the Transfer Case Selector Switch in all positions several times.
8. With the scan tool, read DTCs.
  Did the DTC return?
  
  No
  - Replace the Instrument Cluster in accordance with Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE - BODY VERIFICATION TEST .
  Yes
  - Test complete.
  - Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE - BODY VERIFICATION TEST .