P0837 4WD MUX SWITCH PERFORMANCE

When Monitored and Set Condition:

When Monitored: Continuously with the ignition on.
Set Condition: The 4WD muxed switch input detected in an invalid range or irrational switch state.

With the DRBIII(R), read DTCs. Are any other Transfer Case DTCs present?
Yes --> Repair all other Transfer Case DTCs before proceeding.
No --> Go To 2
Verify proper Transfer Case Shifter adjustment. Refer to appropriate TRANSFER CASE article. Is the Transfer Case Shifter adjusted correctly?
Yes --> Go To 3
No --> Adjust the Transfer Case shifter linkage.
Turn the ignition off to the lock position. Disconnect the PCM/ECM harness connector(s).
CAUTION: IF EQUIPPED WITH NGC CONTROLLER, DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WELL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.
Measure the resistance across the Transfer Case Position Sensor signal circuit and Sensor Ground circuit at the PCM/ECM harness connector. Place the transfer case in each of the following positions:
2H - resistance should be between 1124 and 1243 ohms.
4H - resistance should be between 650 and 719 ohms.
N - resistance should be between 389 and 431 ohms.
4L - resistance should be between 199 and 221 ohms.
Were all resistance values in each transfer case position within the specified range?
Yes --> Go To 4
No --> Replace the Transfer Case Position Sensor.
If there are no possible causes remaining, view repair. Repair Replace and program the Powertrain/Engine Control Module. Refer to ELECTRONIC CONTROL MODULES . Perform the appropriate Powertrain verification test.