If I’m not mistaken, Nissan’s that year would blink out a code on the ECU itself. My 90 Maxima would. I cannot remember how to trigger it but I don’t remember it being too hard.
Instead of settling for the pitiful offers of the dealerships, why not Ebay the truck if you are ready to sell. Some other states may accept the vehicle without emissions testing (Alabama, my state would) and you might be surprised what others may offer for the vehicle with a known issue. especially a Nissan truck from cosy California