On the ACDelco site, I could enter the vin, and it would pull up part numbers for PCM, but wouldn't show any calibration codes. I want to re-check my work on the testing for C2 23. I just want to confirm with you that you are talking about probing the c2 #23 on the harness, correct? I was thinking that it was getting its power through the ABS/PCM fuse, which is hot when key is in the ON or Start position. Please confirm you are talking about the harness connector for this pin, and not the actual pin on the PCM itself. I will re-test this just to make sure.

 

Check out post #8 above with the wiring diagram for the crank circuit that feeds power to the PCM during only start position on the key switch. On the connector harness i want to see if we have 12v during cranking only. If you can test connector C2 pin 23 with the pcm connected would be preferred but if not then unplug and test that harness side pin for voltage.

 

I tested the PCM wiring harness C2/23 when ignition in crank position and am NOT getting voltage. I then tested the PCM CRANK 10 amp fuse when key turned to crank position and NOT getting power to that fuse. This tells me the ignition switch is not sending the power to the PCM CRANK fuse when the key is turned to the crank position. Since this has been the problem all along, and I have replaced the entire ignition switch (keyway, cylinder, switch housing, etc.) and that didn't fix the issue, I am not sure how to diagnose from this point. After the replacement of the ignition switch, the relearn seemed to work and I no longer have a security light. Any thoughts on how to diagnose why voltage is not being sent from the switch to the PCM Crank fuse? I know there are two large harnesses and then the small 3 wire harness (That contains the small yellow wire from the cylinder) connector that connect to the Ignition switch.

 

Sounds like we are getting somewhere. Glad you found something. As you can see in that wiring diagram there is two connection points before it gets to the crank fuse. One is at the ignition switch itself and the other is at the fuse panel. I would start with checking for voltage on the yellow wire at the ignition switch itself right where it plugs in. If you have voltage there when you turn it to start then check to see if you have voltage at the fuse panel harness plug. If you don’t have it there then check for continuity between the ignition switch and fuse panel harness plug. The pin and connector is identified in the wiring diagram shown in a previous post. From what I recall seeing there is another harness plug behind the left instrument panel fuse block. One on the fuse side which you tightened and the other is on the backside which you cannot see. Maybe that one is loose like the other or there is a pin issue in the connector. In the diagram above I have highlighted that circuit. Just trace it tru with the meter and see where you loose voltage at.

 

I will definitely start checking this stuff out. Do you know how the fuse panel harness plugs connect/unhook from the fuse panel? I did check the other one you are referring to on the back side and it seemed tight. To remove these, do I just remove/loosen the one bolt and then does it pull away from the fuse panel? I just don't want to mess anything up.

 

Yes, once you remove the bolt (which will stay in the connector) it will pull out. The connector shown closest to you when you open the fuse panel door is C2, The one you are looking for is C1 which is behind the fuse block. I attached a procedure to remove the fuse block. When testing for voltage you will need to have everything plugged in since It appears ignition voltage wires go thru this fuse block.

 

First, I want to thank you for sticking with me and walking me through all of this. I hope that I can return the favor sometime. If you ever in the western Kentucky area, let me know and we can take a fishing trip to KY Lake or something. I wanted to let you know that I finally figured this out. Since I was not getting power at the PCM crank fuse when ignition turned to start, I pulled the ignition out of the dash again and back probed the little yellow wire at the ignition switch per your advice. No power at the switch either. I then started really looking and thinking about everything I have gone through. After the lighting strike the car wouldn't start. My scanner also wouldn't communicate through the OBD II. Since I had the no start and the security relearn wouldn't work, I replaced the entire ignition switch including the keyway, cylinder and switch module. I purchased all of these parts from Rock Auto and only bought the GM Genuine parts and replaced them all. Since I had determined that the PCM was also fried, I replaced the PCM. Replacing the PCM solved all my communication problems and replacing the ignition switch, keyway and cylinder resolved my relearn issue, but car would still not start. Looking at the new switch purchased from Rock Auto, I remembered that it looked a little different that my original. My original switch module was black and white. The new one that came in a GM genuine part box from Rock Auto was all black. It also had a sticker on it that said "Made in China". I didn't think much of it at the time and thought maybe GM had just changed suppliers. The picture on the Rock Auto website also showed a black and white module just like my original. While I had it pulled out, I removed the new GM cylinder from the new switch and grabbed my original switch and installed the new Cylinder & Keyway in the original switch, and the car started right up like it should. After thinking about it, I think someone bought a new GM Genuine switch part # D1432D from Rock Auto and then returned a cheap China knockoff to them for a refund. Then they sent that part to me as a Genuine GM part. Since I am past the 30 day refund period, my guess is that Rock Auto will not want to refund me for this, but I am sending them an email. This is definitely going to make me second guess ever buying parts from Rock Auto or any other online retailer again. This has cost us countless hours and has cost me a lot of $$$$ trying to figure all of this out. Again, thank you for you continued help on this and all the information you provided. I wanted to make sure to follow up with you and anyone else following this thread on what I finally found.

 

You're very welcome!! So great to hear it is now running again. Best news all day!! I never was a fan of the cheap parts you can sometime find on Rock Auto and it sounds like they did you wrong by the wrong part in the box for sure. I would pursue this as well for them to make it right. We will have to go fishing something, that sounds fun for sure. Do you also turkey hunt?

 

@davidh0765 - WOW! NICE summary that leads to a successful win! This thread has been a LOT to review and you and @02MonteSS_D.E. have gone through a LOT! Very impressed to see all the communication and back and forth eventually ended in a huge win!

I have used RockAuto for many many years. They offer all the name brand parts that the same parts the local stores offer and many times offer some cheaper/lesser/no-name brands as well. Sometimes it pays to get the better brands. I have also seen where Rock has sometimes had incorrect descriptions or pictures (and this is a based on what the part manufacturer provides them). They have always made good with me when I have had issues. Hard to say what is the story with that ignition switch. May have been someone did something shady, may be GM changed supplier. But 100% agree, reaching out to Rock is worthwhile and perhaps they can offer something. A big item to explain would be how long the troubleshooting of this issue went on to lead to finding a new and faulty part.