2015 Silverado Won't Start!

[enroberts]

Hey all.  Hoping for some help!  Started my truck this morning for the first time in about a week. When I pulled out of my driveway the DIC told me to service pretty much every system in the truck (trailer brakes...no trailer attached, Stabilitrak, power steering...drive with care, 4x4, etc) and the steering wheel became ridiculously heavy with speed and tach both at 0 while moving/running.  I threw a brand new battery in it but still nothing.  The video below is AFTER the new battery was installed.   It's like the ECM isn't getting 12v or ground. The fuel gauge shows empty, which it's not, the trans isn't showing what gear it's in, and there's absolutely no cranking. All fuses are fine.

 

 

[diyer2]

Electrical problem.

Any chance mice got to it?

Chewed wires?

 

[Hillwood]

Clean and tighten battery ground at engine block.. Sounds like a low voltage concern.. clean and tighten ground wires fom battery to engine block , battery to fuse block.. don't over look any.

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[diyer2]

6 minutes ago, Hillwood said:

Clean and tighten battery ground at engine block.. Sounds like a low voltage concern.. clean and tighten ground wires fom battery to engine block , battery to fuse block.. don't over look any.

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Good idea!!

Check all grounds.

[Supreme Pizza]

Hmm. That's a tough one. 

 

You could have an internal alternator fault. You might try disconnecting it, to see if that helps. 

 

To check your ground, you can take a small wire and attach it to the negative battery terminal (not the cable, but the actual terminal itself), with both cables hooked up to the battery. Then connect that small wire to the body and the engine. Then start using electrical stuff, like the starter, head lights, etc. If the small wire gets warm or hot, or the electrical components work properly, then you definitely have a ground issue. I would also grab a volt meter, and start probing stuff. If you put the negative probe on the negative battery terminal, and probe the brake light or headlights (when they are tuned on), are you getting 12+? If so, is it constant or does the voltage wander around? You might also look at any fuseable links and any main power relays. You can swap relays around to test them. 

 

Wiring is not much fun.... 

 

 

 

 

 

 

Edited December 15, 2018 by starman8tdc

[enroberts]

Thanks for all the quick replies!  I was just able to get my code reader to finally connect and pull codes.  The only code is U0100 which is Lost Communication With ECM/PCM "A"

[Hillwood]

Start with the basics... Like I stated!


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[Hillwood]

U codes are communication codes... LOW VOLTAGE LOSS OF COMMUNICATION!

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[enroberts]

all grounds and 12v check out as expected.  Maybe the ECU took a crap?

[Supreme Pizza]

If everything electrical looks good, I would remove the ECU and "smell it". Does it produce an odor of burnt electronics? Is it wet? Any signs of heat damage to the outer case? 

 

Also, you could clean the connections to the ECU, and maybe throw some dialectic grease at it. 

 

 

[enroberts]

ECU looks fine, smells fine.

[Supreme Pizza]

 

      I hate to say it, but you might be looking at a diagnostic shop. Running low on options. 

 

      If you go down that path, try to find one that will guarantee a diagnosis without exceeding 1 hour ($100-$150). Most won't, but some will. 

 

      Some repair shops will charge you $900 in diagnostics, and then say it needs a $1200 part. Then $2100 later, the problem is still there. Then they say: Oh, well that part needed to be replaced, but there must be another part that is bad as well. We will put our diagnostic guys back on it (after you pay this first bill). 

 

     I have seen people spend thousands on diagnostics and parts, with no remedy. 

 

     Not trying to scare you, just trying to caution you.

 

     Call 5 or 6 shops and talk to them a bit before you choose one. 

 

     If I can think of any other tests you could try, I will post it. 

 

     Good luck. 

 

 

P.S.

 

https://repairpal.com/obd-ii-code-u0100-lost-communication-with-ecm-pcm-a

 

https://www.obd-codes.com/u0100

Edited December 15, 2018 by starman8tdc

[SS502]

I’m pretty sure it has nothing to do with it but those gauges I saw in the video, are they newly installed? Yeah grasping at straws but as mentioned, this could get ugly.

[tbarn]

I will guarantee you there a many more codes in the system. Need a proper scan to start with.

[enroberts]

4 hours ago, SS502 said:

I’m pretty sure it has nothing to do with it but those gauges I saw in the video, are they newly installed? Yeah grasping at straws but as mentioned, this could get ugly.

No, factory gauges.