My '95 D-90 is trying to tell me something, I'm getting a code 48, which I believe tells me to look at the stepper motor, a solinoide??? maybe needs cleaning??? I think I found it, left side lower plenum chamber??? I removed this, how do you clean it??? I just put it back, reset check engine light, a few days later I'm getting a code 48... Am I on the right track? did I find the stepper motor? is it cleanable? do I just replace it?
The truck runs great, but that check engine light is on....