http://forums.corvetteforum.com/show...p?p=1566850782

 

ttt

 

Gee, no ideas from anyone??? What happened to all the knowledge here?

 

So I went ahead and read your post from the scan and tune. Here is what I can offer you:

1. Engine computer codes do not set the flashing SYS warning (unless it is a data link failure but that is a different matter). So if you have the flashing SYS warning on your speedometer, you need to look at the error codes for the CCM. ECM error codes set the Service Engine Soon light on the dash.

2. In the FSM for my 92, a code 25 is for the courtesy lamp relay coil circuit (open or shorted to ground). I would double check this with information for your car if I were you.

So forget your temp sensors... they are most likely fine and check out something going on inside your car.

Matt

 

Thanks so much Matt. As I originally stated I hadn't received my FSM I ordered. (still don't have it) I also knew I was dealing w/a H25 in the CCM, not PCM. However when another member offered to send me a couple scanned pages from his FSM, apparently he sent the TS procedure for a H25 in the PCM, which is related to the IAT sensor.

However as per my tests related to that, I discovered when that set a code, it was in module 4, the PCM so I know something wasn't right. Basically I was waiting until I got my FSM to see what else I could learn. But your info goes a long way toward figuring out what the issue is. Also explains why when I disconnected the IAT it threw a low code, but in the PCM module. I felt strongly that it the H25 in the CCM was trying to tell me something else, but I had no idea what.

Now I have a better idea where to look, but still don't know what/where the courtesy lamp relay coil circuit consists of. Can you tell me where the relay is located? Or of course I can just wait until my FSM on a slow boat from somewhere arrives.

Thanks once again Matt. You input is very much appreciated!

 

Ok... it is under the dash on the passenger side (right) of the car. You have to remove the kick panel on the bottom of the dash to get to it. Do this VERY CAREFULLY if you have not done it before! It is easy to break the tabs that hold it in place because the plastic is getting old.

Try this:

1. Remove the main fuse block cover.
2. Remove the panel that the fuse block cover attaches to. (3 screws)
3. Pull back the carpet that covers the kick panel. It is velcro'ed to the panel. Be careful here!
4. Remove the screws that hold the kick panel in place. There should be four of them, maybe less.
5. Firmly but carefully remove the kick panel. You will have to tweak it a little but it will come out. If it resists too much check to see that you removed all the screws. When it is mostly out be sure to disconnect the courtesy light.

Once the panel is off you will find several relays under the beam that runs across the dash. (You will have to crawl under there a little.) The courtesy light relay is the second one inboard from the far right side of the car. It is pared together with one other. Leave the relays that are grouped three together alone. (Just so you know the other relay that is paired with the courtesy lamp relay is the fog light relay)

If you need electrical troubleshooting help let me know but I probably will not be on tomorrow. Also keep in mind that the information above is for a 92. Things could possibly be different in your 95 but I doubt it.


I hope you get it worked out.

Matt