Hi guys new to the group. I just picked up a 04 SS and it cranks no start. No power to the icm which traces back to no power the the 15a fuse in the under hood box. Well the 2 bottom rows of the fuse box has no power at all I took the fuse box apart didn't c anything. I did swap some relays around thinking mayb that would help. I can't find any wiring diagram past the fuse box. It say pink wire to the fuse box hot in run but both sides are dead. I did take my power probe and put power to the wire and the car runs. But I can't figure out y I don't have power the fuses. Thanks for the help

 

Could be several things, but the most common is a breach in the theft deterrent system that's not allowing the stored passcode to be passed between the BCM, PCM and chip in the ignition lock cylinder. This causes the serial data link to be incomplete. Could be the crank relay, ignition switch housing, ignition lock cylinder, bad ground or power wire or connection.

Do you have a flashing security or battery light in the dash when you turn the key to on?
Have you tried a 30 minute security re-learn procedure?
Do you have an aftermarket stereo or alarm?

If you have any of the above three, it's a theft deterrent issue, otherwise it's in the ignition circuit.


Here's a link to a previous thread where I posted circuit descriptions and schematics.

Hope it helps, please keep us posted.

https://montecarloforum.com/forum/mo.../#&gid=1&pid=7

 

I bought the car wrecked. The battery was complete dead so I put another battery in it. Yes it did have a aftermarket stereo but it was takin out and now has the factory unit back in it. Also when the key is in the off position the dash lights and radio stay on even when u pull the key out. I'm doing the security re learn now so hopefully that helps. I was assuming/ hoping the key issues and no start were separate issues. The interior was pretty well completely taken apart when the air bags were replaced and stereo swapped back but I have all that back together now

 

The radio wiring connections sound very suspect. It should not be always on. Sounds like it got connected to a always hot wire. The factory alarm is integrated with the radio through the serial data link and part of the theft deterrent system. I would focus there. I doubt the security re-learn will work until you get the wiring straightened out. I believe the key and no start issues are the same problem.

 

Ther wiring was never cut for the radio. When I the key is in the off position or out the gear letters and battery light stay on. No the re learn didn't do any good. I pulled the ign switch a and cleaned the contacts but no change either. I'm thinking it's the ign switch

 

I agree, either the ignition switch housing needs more than cleaning, or the ignition lock cylinder is bad. Stick with ACDelco. You will need to do a relearn after replacing an ignition lock cylinder

 

Update... I replaced the ignition switch and got a junk yard lock cylinder. Did the relearn thing and now the car shuts off as should. But no luck fixing the no start. Still have no powe to the j8- j9 fuse or any of the bottom 6 fuses. But I also lost my signal voltage to the fuel pump relay. I put my relay jumper kit on it and if I put power to the pump works like it should. Just not getting signal to activate the relay. Really got me at a lost. The Haynes manual doesn't help much with the wiring. I took the back off the fuse box under the hood and it looks like the power comes from a thicker green wire that jumps around and feeds other things but I can't really tell where it goes or y it's not getting power.

 

I posted a link to another thread with similar problem early in this thread. That link has several schematics attached to it, one of them covers "fuel controls"

In case you didn't see it, here it is again: https://montecarloforum.com/forum/mo.../#&gid=1&pid=7

 

So after getting on alldata my fuses weren't getting power becuz the ign relay wasn't getting ground. All the wiring diagrams besides alldate just show power to the fuse and that's it. But I still don't have signal from the pcm to turn the fuel pump relay on. What tells the pcm to turn the pump on?? Or what will keep it from not turning on??

 

The PCM needs to have the same passcode stored in it as the BCM and the chip in the ignition lock cylinder. That code is passed through the serial data link and once confirmed the code is correct, ignition and fuel delivery is enabled. A short or bad ground anywhere in the circuit will keep the code from being passed through. Have you checked the ground connection and continuity of the group of 3 wires connected to the transmission bell housing stud under the air intake duct? There should be one thicker cable with it's own loop connector, and two smaller wires that share one loop connector attached to that stud. I once had symptoms similar to yours after a tranny swap. I had the starter cable and the cable to the stud switched around. After straightening out I had to do a security re-learn.

One of the thumbnails in my previous post (includes schematics) has a description of the starting system from the factory service manual.