1993 G-20 emissions problem

Hello I am not mechanic but I have to say use paper clip for read the codes in your van if any. When the key is in off position put the two ends of the paper clip in the obdi connector is in under the dash in the steering area right side of the steering. The A AND B is in the upper right side in the obdi connector. After turn the key in on position but without start the engine look in the check engine light. The engine lights start make flashes. One short flash and after follow for two more flashes is code 12 this mean the computer not have stored any codes. If after you see more codes write down how many times the engine lights flash and look on the internet for OBDI codes what mean any flash. For example my van show codes. 3 flashes and follow from 7 more flashes is code 37 tcc brake switch stuck on. 3 flashes follow from 8 more flashes tcc brake switch stuck off 4 flashes follow 4 more flashes is code 44 lean exhaust. I hope my answer help you. Answer me when you found what wrong part is in your van