Quad drivers are in the computer. The computer has to be replaced. The most likely cause for the code 31 is PRNDL switch gone bad. It should be located on top of the transmission on the shift linkage.
where is the computer located
It is either in the engine compartment are under the dash. Hold on and I will look it up for you.
It is behind the glove box kind of on the right. It will have three electrical plugs going to it.
ok. Now what is required to replace the computer. is it as simple as unplugging the bad cpu and plugging in a new one, or is there other steps required
Replacing it is simple as unplugging and replacing. the one trick is to check the resistance of all the out put devices such as fuel injectors, solenoids like the torque converter clutch, EGR, ect. Most replacement computers will have a list for you to check with the correct pin numbers to check between.
One of these components are probably bad and that's what caused the drivers to fail
ok. now how do i replace the prndl switch.
First look on top of the tranny and find the shift cable. Remove the shift cable and the electrical plug then the two mounting bolts. Pull old switch off. Install new switch aligning the flats on the shaft with the ones on the switch. Leave the mounting bolts loose. Using a 3/32 drill bit into hole in switch rotate switch until bit drops into another aligning hole. Tighten mounting bolts and reinstall electrical plug and shift cable.