Failure Conditions
WARNING: This page is about a different car, the 1991 Oldsmobile Custom Cruiser, 1991 Chevrolet Caprice, and 1991 Buick Roadmaster. However, it is still accessible from the selected car via links, so may be relevant.
Code 31 will set if voltage at SENSE LOW input is 28-59 percent of IGNITION 1 output voltage for 700 milliseconds and Code 42 is not set.