P0839

P0839 - Four Wheel Drive (4WD) Switch Circuit High






- When Monitored:
With the ignition on and no system undervoltage or overvoltage or supply voltage low conditions present.

- Set Condition:
The Transfer Case Selector Switch Voltage is above a specified value for a calibrated amount of time.






1. DTC IS ACTIVE

NOTE: If any other DTCs are present they must be repaired before continuing.

1. Turn the ignition off to the lock position
2. With the scan tool, read DTCs in the CCN.

Is the status Active for this DTC?

Yes
- Go To 2

No
- Go To 4

2. TRANSFER CASE POSITION SENSOR SWITCH VOLTAGE GREATER THAN 4.5 VOLTS

NOTE: Repair any system undervoltage or overvoltage DTCs that are set in this module before proceeding.

1. Ignition on, engine not running.
2. With the scan tool, read the Transfer Case Position Sensor Switch voltage in the CCN.

Is the voltage greater than 4.5 volts?

Yes
- Go To 3

No
- Go To 4

3. (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT SHORTED TO VOLTAGE






1. Turn the ignition off to the lock position.
2. Disconnect the Transfer Case Selector Switch harness connector.
3. Disconnect the CCN C3 harness connector.
4. Measure the voltage of the (K77) Transfer Case Position Sensor Input circuit at the Transfer Case Selector Switch harness connector.

Is the voltage above 0.2 volts?

Yes
- Repair the (K77) Transfer Case Position Sensor Input circuit for a short to voltage.
- Perform BODY VERIFICATION TEST - VER 1.

No
- Replace the Transfer Case Selector Switch.
- Perform BODY VERIFICATION TEST - VER 1.

4. INTERMITTENT WIRING AND CONNECTORS

1. The conditions necessary to set this DTC are not present at this time.
2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
3. While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
4. Look for the data to change or for the DTC to reset during the wiggle test.
5. While monitoring the scan tool data relative to this circuit, move the selector switch to each position several times.
6. Look for the data to change other than as expected or for the DTC to reset.

Were any problems found?

Yes
- Repair as necessary.
- Perform TRANSFER CASE VERIFICATION TEST.

No
- Test complete.