Modern cars have on-board diagnostic computers. The computers store and transmit codes relating to faults sensed by the on-board diagnostic system. Chevy Code P1875 relates to the four-wheel drive low-switch.
In Chevrolet vehicles, code P1875 is given the description "4WD Low Switch Circuit Electrical." A fault has been sensed in the electrical switch circuit for the low setting of the four-wheel drive when this code appears.
Four-wheel drive low is used when towing a heavy trailer or driving off-road. It is helpful when low-speeds with high torque are useful.
The problem sensed is within an electrical circuit that connects the Vehicle Control Module to the Transfer Case Control Module, specifically the four-wheel drive low-input of the TCCM. It is possible to test and fix the circuit with the appropriate Chevrolet wiring diagram.
