Normal Operation

The instrument cluster receives the 4WD status from the 4WD control module over the high speed controller area network (HS-CAN) communication bus. When the 4WD mode switch is in the 4WD high position, the 4WD high (4x4) indicator illuminates. When the 4WD mode switch in the 4WD low position, the 4WD low (4x4 LOW) indicator illuminates.

DTC U0102 (Lost Communication With the Transfer Case Control Module) - is a continuous DTC that sets in the instrument cluster if the 4WD status message is missing for more than 5 seconds and the instrument cluster illuminates both the 4WD high and 4WD low indicators.

This pinpoint test is intended to diagnose the following:

4WD control module
Instrument cluster

FOUR-WHEEL DRIVE LOW/4WD HIGH INDICATOR PINPOINT TEST 19

PINPOINT TEST 19		THE FOUR-WHEEL DRIVE (4WD) LOW/4WD HIGH INDICATOR IS NEVER/ALWAYS ON
STEP	INSPECTION		ACTION
1	CHECK THE 4WD OPERATION Verify the operation of the 4WD function. Does the 4WD function correctly?	Yes	Go to next step.
1		No	Go to SYMPTOM TROUBLESHOOTING CHART - DRIVELINE / AXLE .
2	RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND INSTRUMENT CLUSTER SELF-TESTS Retrieve the recorded DTCs from the instrument cluster continuous and on-demand self-tests. Is DTC U0102 retrieved?	Yes	If DTC U0102 is retrieved, CLEAR the DTCs. REPEAT the self-tests. If DTC U0102 is retrieved again, go to next step. For all other DTCs, See DTC Index - 4WD
2		No	Go to step 4.
3	CHECK THE NETWORK OPERATION Enter the following diagnostic mode on the scan tool: Network test Does the 4WD control module pass the network test?	Yes	Go to step 5.
3		No	DIAGNOSE the module communication network. See Pinpoint Test 5: No Controller Area Network (CAN) Communication .
4	CARRY OUT THE INSTRUMENT CLUSTER 4WD TRANSFER CASE CONTROL ACTIVE COMMAND USING THE SCAN TOOL Key in ON position. Enter the following diagnostic mode on the scan tool: Instrument Cluster DataLogger Select the instrument cluster 4WD low (LOW_LAMP) or 4WD high (HIGH_LAMP) active command. Command the 4WD low or 4WD high warning lamp on then off again. Observe the 4WD low or 4WD high indicator. Does the 4WD low or 4WD high indicator illuminate when commanded on and turn off when commanded off?	Yes	Go to next step.
4		No	Go to step 6.
5	CHECK FOR CORRECT 4WD MODULE OPERATION Disconnect all the 4WD module connectors. Check for: corrosion damaged pins pushed-out pins Connect all the 4WD module connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	INSTALL a new 4WD module. See 4WD Control Module Removal / Installation . TEST the system for normal operation.
5		No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
6	CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION Disconnect all the instrument cluster connectors. Check for: corrosion damaged pins pushed-out pins Operate the system and verify the concern is still present. Is the concern still present?	Yes	INSTALL a new instrument cluster. See Instrument Cluster . TEST the system for normal operation.
6		No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.