this car is a pain in the a*#

[ifixjeeps]

i am working on a 93 pa ultra the service engine light goes on and off at will ihave scanned the vehicle watched all the data and every thing is in paramaters the only code is quad drive b malfunction the only good thing is when i put the car in reverse with the brake on the light will stay on untill i put the car in any other gear alldata has crap info on this. any help would be grand

thanks

[HotZ28]

The 93 Ultra uses (QDM) Quad driver modules.
They temporarily shut down, set a fault code, and then reset if a device or its circuit shorts.

This link should help!