Hello, a baisc code reader will only pull codes for the engine so I imagine you didnt get any codes for the 4x4 system. It could be an issue with the PTO(transfer case for the*****system but you would need to identify what codes are stored for the 4x4 system first.Here is what informationyou can get based on the what the light for the 4x4 is doing:
4WD Indicator Light
4WD — Illuminates continuously when the 4WD system is locked in 4WD due to its heat protection mode. In the locked mode, the vehicle resists turning and binds up when driven on dry pavement. To exit the locked mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the 4WD indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks continuously when the 4WD system is disabled due to its heat protection mode. To exit the disabled mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks 3, 6, 8 or 10 times every minute when the 4WD system requires service. Use a scan tool to check for diagnostic trouble codes (DTCs). Refer to the Four-Wheel Drive (4WD) Control Module Diagnostic Trouble Code (DTC) Index in this section.
3Cluster is not receiving the 4WD indicator message from the 4WD control module
6Invalid throttle position data received from the PCM
8Invalid wheel speed data received from the ABS module
10Active torque coupling circuit fault