Service Four-Wheel Drive Indicator Always On. GMC Truck Canyon Pickup

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2004 🢒 Canyon Pickup - 4WD 🢒 Driveline/Axle 🢒 Transfer Case - Isuzu T150 🢒 Service Four-Wheel Drive Indicator Always On

Circuit Description

The Service 4WD indicator is located in the instrument panel cluster (IPC), and shares the common power and ground of the IPC. The transfer case shift control module controls the Service indicator by sending the IPC a Class 2 message. This indicator may be controlled with the scan tool using the IPC device controls.

Test Description

The number below refers to the step number on the diagnostic table.

This step determines whether the condition is the result of a malfunctioning transfer case shift control module or the IPC.

Step	Action	Yes	No
Schematic Reference: Transfer Case Control Schematics Connector End View Reference: Transfer Case Control Connector End Views
1	Did you perform the Diagnostic System Check - Transfer Case?	Go to Step 2	Go to Diagnostic System Check - Transfer Case
2	Disconnect the transfer case shift control module connectors C1 and C2. Is the Service 4WD indicator still ON?	Go to Step 4	Go to Step 3
3	Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the repair?	Go to Step 5	--
4	Replace the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console. Did you complete the repair?	Go to Step 5	--
5	Use the scan tool in order to clear the DTCs. Operate the vehicle to determine if the symptom has been corrected. Is the symptom still present?	Go to Step 1	System OK