C1402

C1402-TRANSFER CASE RANGE SELECT SWITCH CIRCUIT HIGH





For a complete wiring diagram refer to diagrams.
^ When Monitored:
With the ignition on and no system undervoltage or overvoltage condition present.
^ Set Condition:
The sensed voltage is greater than a specified voltage for a calibrated amount of time.

Possible Causes

- INTERMITTENT TRANSFER CASE RANGE SELECTOR SWITCH CIRCUIT HIGH
- (K77) TRANSFER CASE POSITION SENSE CIRCUIT SHORTED TO VOLTAGE
- (T525) TRANSFER CASE RETURN CIRCUIT SHORTED TO VOLTAGE
- TRANSFER CASE POSITION SENSOR
- FINAL DRIVE CONTROL MODULE

Diagnostic Test
1. 4WD RANGE SWITCH VOLTAGE ABOVE 4.5 VOLTS
Ignition on, engine not running.

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

With the scan tool under Data Display, read the 4WD Range Switch voltage.

Is the voltage above 4.5 volts?
Yes >>Go To 2
No >>Go to 6

2. TRANSFER CASE POSITION SENSOR
Turn the ignition off.
Disconnect the Transfer Case Position Sensor harness connector.
Ignition on, engine not running.
With the scan tool under Data Display, read the 4WD Range Switch voltage.

Is the voltage equal to 0 volts?
Yes >>Replace the Transfer Case Position Sensor.
Perform the FDCM VERIFICATION TEST.
No >>Go to 3

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





Turn the ignition on.
Measure the voltage of the (K77) Transfer Case Position Sense circuit.

Is the voltage above 5.5 volts?
Yes >>Repair the (K77) Transfer Case Position Sense circuit for a short to voltage.
Perform the FDCM VERIFICATION TEST.
No >>Go to 4

4. (T525) TRANSFER CASE RETURN CIRCUIT SHORTED TO VOLTAGE





Turn the ignition off.
Disconnect the Final Drive Control Module harness connector.
Turn the ignition on.
Measure the voltage of the (T525) Transfer Case Return circuit.

Is there any voltage present?
Yes >>Repair the (T525) Transfer Case Return circuit for a short to voltage.
Perform the FDCM VERIFICATION TEST.

No >>Go to 5

5. FINAL DRIVE CONTROL MODULE
Repair
Replace the Final Drive Control Module in accordance with the Service Information.
Perform the FDCM VERIFICATION TEST.

6. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
While monitoring the scan tool data relative to this circuit, move the selector switch to each position several times.
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 the FDCM VERIFICATION TEST.
No >>Test complete.