Have heard that the codes in the V-6 can be retrieved. Using a jumper on the 15 pole connector, on the drivers side fender well. The 6 and 7 pin should be jumped, the ignition turned on and the number of flashes counted, on the engine trouble, dash light. Code 12 indicates normal operation, anything else is a problem code. Believe the codes are Chevy, standard codes.
Having never done this myself, on a mid 80´s Jeep, I´d research it a little more, before attempting it.
Unless you have a constant trouble light, the problem is usually not computer related, but most often something else. Either standard automotive stuff or sensor related. Even sensor codes, often turn out to be something else. All the codes, usually tell you, is that a particular sensor is registering, out of parameter readings. Might be the sensor, might be the wiring, might be something in the motor. Bad valves, poor compression, missfires and other things, sometimes show up as trouble codes.
