No start no crank I checked my fuse block under-hood?

Tiny
BRIANNAAALETA
  • MEMBER
  • 2007 GMC YUKON
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 175,000 MILES
I was checking my fuse block under hood and ECM wiring harness making sure all the pins were in there correct and they were all there. I plugged everything back like it was supposed to be or I thought and now my truck isn't starting, it isn't cranking with the key. When I tried to crank the truck, the doors locked. There is power in the fuse block because it will try to crank when I try jump the starter off, but it will just turn over so I'm thinking somewhere between the fuse block and ignition. Does anyone have any advice?
Thursday, September 8th, 2022 AT 8:13 PM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
When you are trying to check the engine over does the security light flash? If so, this is your problem, try to disconnect the battery overnight to see what happens. This should reset the system this guide can help as well:

https://www.2carpros.com/articles/how-to-reset-a-security-system

Please go over this guide and report back.

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Friday, September 9th, 2022 AT 1:40 PM
Tiny
BRIANNAAALETA
  • MEMBER
  • 8 POSTS
The security light doesn't come on. The vehicle will start if you press the starter relay run crank relay and fuel pump relay it will run, and the key won't cut it off. You have to pull the run crank relay to turn it off. The battery has been unhooked for a couple weeks if not months but every time I walk away from it, I will disconnect the battery.
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Friday, September 9th, 2022 AT 6:48 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I would go back over the wiring connectors to make sure they are all the way seated. Also, use a flashlight to see if any of the pins have been rolled over and are not in the terminals of the connector. If they look okay, we should do a CAN scan which is easy to do, you can get a CAN scanner (Controller Area Network) from Amazon for about $30.00.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

Here is a scanner link:

https://amzn.to/3o41KcZ

Let me know what you find.
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Saturday, September 10th, 2022 AT 2:34 PM
Tiny
BRIANNAAALETA
  • MEMBER
  • 8 POSTS
P1682
P0134
P0300
C342d
P0055
C3064
C3064
C2174
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Sunday, September 11th, 2022 AT 6:05 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
So, the vehicle was okay until you unplugged the PCM? Did you recheck the connector using a flashlight to see if any of the pins are rolled over?
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Monday, September 12th, 2022 AT 3:59 PM

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