Everything was fine this morning, driving to and from church. Perhaps a half hour or an hour after getting home from church, we went to a friend's house, and I noticed, as I started the car, that the ??O/D Off? light was on. It stayed on when I worked the O/D button.
On doing some further testing, it seems that the transmission is shifting correctly through all its gears, including 4th. In other words, it seems that the transmission itself is fine, and that the malfunction is just in whatever causes that light to be on.
I hooked up my Alex Peper OBD??II system to the car, hoping to see if there were any error codes or anything that might clue me in to the problem, and I found that it wouldn't connect. The event log shows it cycling through every variation of the three standard protocols, and failing to see a response to any of them. (Normally, it gets a response, and connects on the first time it attempts the PWM protocol.)
Obviously, I suspect an electrical problem of some sort, but I'm at a loss as to what. Where, in the electrical system, is there a poinjt where a failure would cause these two symptoms?
Anyone got any ideas?
