Jump to content

2015 Silverado Won't Start!

enroberts

By enroberts
in Troubleshooting & Recalls

 Share

Recommended Posts

enroberts Enthusiast

enroberts

Posted
Posted

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.

 

 

  • Replies 33
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

tbarn
tbarn

Not really wasting time. You have to get to the bottom of the issue. Is the doctor wasting time diagnosing? This thing ain't no 78 Cheyene. They are complicated.

enroberts
enroberts

For those interested, my ECM failed. Replaced it at the dealer today and had it reprogrammed. Back in business!   Sounds like an expensive trip to the dealer for them to waste a bunch of t

Posted Images

diyer2 Senior Enthusiast

diyer2

Posted
Posted

Electrical problem.

Any chance mice got to it?

Chewed wires?

 

:)

Hillwood Enthusiast

Hillwood

Posted
Posted

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.

Sent from my SM-G965U using Tapatalk

diyer2 Senior Enthusiast

diyer2

Posted
Posted
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.

Sent from my SM-G965U using Tapatalk
 

Good idea!!

Check all grounds.

:)

Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
Posted (edited)

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.... 

 

 

 

 

f492ab0a97de7483630f4aba5c13105b.jpg

 

 

Edited by starman8tdc
enroberts Enthusiast

enroberts

Posted
  • Author
Posted

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 Enthusiast

Hillwood

Posted
Posted

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

Sent from my SM-G965U using Tapatalk

Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
Posted

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. 

 

 

Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
Posted (edited)

 

      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 by starman8tdc
SS502 Senior Enthusiast

SS502

Posted
Posted

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 Senior Enthusiast

tbarn

Posted
Posted

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

enroberts Enthusiast

enroberts

Posted
  • Author
Posted
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. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,924
    Total Members
    8,960
    Most Online
    KirbyCo
    Newest Member
    KirbyCo
    Joined

  • Who's Online   7 Members, 0 Anonymous, 1,448 Guests (See full list)

  • Latest Articles

  • Posts

    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      I will be doing that for sure, but I need to solve who has/ where I can find a bidirectional scan tool that will support OBD 1.5. I'm kicking myself because I ebay'ed a Snap On MT2500 that I didn't think I'd ever need anymore. D'oh!! I'd rather not buy another, so I'll contact a few local shops to see if they have one and how much they'd want to do the procedure. I'd rather have the ability to do it myself... I wish there was a modern tool that could do it all, but I'd have no idea what to buy.   The theory with the pulled timing is that it mimics a rich condition. The delayed spark causes incomplete burn and the O2 sensor picks up low oxygen levels. That's interpreted as a rich condition so the PCM pulls fuel and that shows up in the deeply negative fuel trims.
    • Chuck FB
      Joke Thread

      By Chuck FB · Posted

      An ultra wealthy man had the most beautiful daughter. But, there was a problem. Everything she touched would melt in her hands. No matter what, Metal, Wood, Stone. Anything she touched would melt. She could not feed herself. Because of this, men were afraid of her. Nobody would dare marry her. Her father was despaired. What could he do to help his daughter? He consulted doctors, scientists and anybody who could solve this problem. Finally one of them said, "If your daughter touches one thing that does not melt in her hands, she will be cured." He was overjoyed and came up with a plan. The next day, he held a competition. Any man who could bring his daughter an object that would not melt in her hands would be given billions of dollars to marry her. Three extremely intelligent and handsome young men took up the challenge. The first brought a very heavy steel rod, But alas, when the she touched it, it completely melted in a matter of seconds. He sadly went away. The second brought a beautiful diamond, knowing diamonds were one of the hardest substance in the world and would not melt. But alas, once she held it in her hand, it melted. He too was sent away disappointed. So now, there was one left He was very nervous & sweating. He approached the daughter & said, “put your hand in my pants pocket and feel what is in there." She did exactly what he asked. She felt something very hard. She held it in her hand, squeezing it as hard as she could. It did not melt & remained extremely hard. Her father was overjoyed. Everybody was overjoyed. She was finally cured. Nothing never, ever melted in her hand again. They married and they both lived happily ever after, raising a wonderful family. Question: What was in the the groom’s pants pocket??? Answer below ↓ M&Ms of course! They melt in your mouth, not in your hand. What on earth were you thinking?
    • asilverblazer
      Wow I'm in a pickle. (Broke down truck) and a story.

      By asilverblazer · Posted

      There's a bunch of tea leaves that you've read, but in any case the delayed timing is unusual. Not sure how that relates to the rich at idle vs. 'normal' while driving.   If you're in this deep, might be worth investigating, and re-learning the sensor. What have you got to lose? Plus, it properly fixes the timing cover leak.
    • asilverblazer
      Wow I'm in a pickle. (Broke down truck) and a story.

      By asilverblazer · Posted

      The only problem I have seen this cause is longer crank times. 
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Injector is being sent off today for rebuild and I estimate I'll have it back in 10 days or so.   It may not be the injector...of course...now that I've torn down the intake again. But, let's rule out the injector and replace those spider legs that have been almost rubbed through.   The truck has always had negative timing and I'm reading "normal" timing at warm idle should be +16 or so. I'm negative 16 to 25 or more, and it's always been like that since I bought it.   A light turned on upstairs last night in the old noggin. Rare, I know...   This will be wild, if it turns out to be the cause!   In 2001, according to the old service documentation, the muffler was replaced. Why? I have no idea, it wouldn't have been rusted through by then. But they did a crappy job.   In 2019, another shop replaced it and noted the prior install was poorly done on the work order. "Exhaust system vibrates on crossmember". Except...I guess they just left it be? I believe the husband, the couple who were original owners, had passed by then. Maybe she said it's just not worth it to have the exhaust system fixed and declined repairs. Very few miles were driven between 2019 and 2025.   The exhaust system vibrates heavily on the crossmember and you can feel it and REALLY hear it, even today. Not always, but at idle, it gets going pretty good sometimes.   What if....   ....What if that's enough to trigger one or both of the knock sensors? Could it be tricking the sensors into sensing knock, so it's pulling timing aggressively? Pulling timing heavily means it's firing after the piston reaches full height which means incomplete burn which means the O2 sensor is sensing a rich condition, which means I've been chasing my tail, and what I thought was an inconsequential problem (janky exhaust) has been THE issue for this truck for 25 solid years?   That would be wild. Maybe it IS wild.   The service documentation thereafter, for years, shows visits for rough idle, replacing O2's, replacing the cat, replacing plugs and wires, a misfire condition, like they could never solve the issue. The injector has been replaced 4 times in 80k miles, that's just crazy.   The secondary theory....   The engine has clearly had a leak at the front seal for a very long time (the greasy trench...). I think the truck changed hands quickly ~2025 because there's Napa receipts from someone I don't recognize in the ownership history. They apparently replaced the timing cover seal, and they did a terrible job. There's RTV smeared all over and the leak I had reduced to a weep by snugging the front oil pan bolts is now a leak again.   HOWEVER....I read about replacing the crankshaft position sensor. Any time the ckp sensor is disturbed or timing cover is removed, the truck requires relearning, and that can only be done through a bi-directional scan tool. Skippy with the RTV probably didn't do the relearn procedure is my guess. His scan tool is lost in a pile of RTV goo somewhere.   So, it's very possible the sensor has been disturbed and the truck is just running on the old learn data but not setting a code for anything. The distributor has since been replaced and so has the camshaft position sensor, so all bets are off for that thing.   In the theme of one step forward, two steps back, I returned the accumulator for the AC. The gal I've been working with at O'Really's has been great. She refunded it under manufacturer's defect and we compared it to the replacement I ordered, and sure enough, the replacement is machined very differently (and a gauge actually fits on it!).   Got it home, installed it, started vacuuming it down.... and I couldn't get good vacuum.   The high side service port, where I replaced the old GM ball valve suspecting that was a source of the previous leak....well, I've clearly exposed whatever pre-existing crack in the line where the service port is welded, and made it much worse. Blessing in disguise? Except there goes another $25, now I'm waiting for a replacement AC line.   In 10-ish days ALL the parts will be here. Rebuilt injector, new exhaust system, new cat, new high pressure AC line.   Oh, did I mention the squeaking ISN'T coming from the AC pump? The truck still squeaks when started, and there were words after I started it with the new AC pump installed. But, there was more to replacing the AC pump for just a squeak. A truck with good working AC is something of value, for the comfort alone.   I've ordered a new harmonic balancer because, 30 years is a good run for one of those. Rule it out. The squeak may be something more sinister, though. I'm worried about that ckp sensor and if it was shimmed correctly, or if the timing set was installed correctly. The squeak may be coming from UNDER the timing cover.   At this point, once I get it put back together, I'm thinking I'll take a 50 mile victory lap and then promptly put it up for sale. This truck is cursed. Betty, from beyond the grave, doesn't want anyone messing with her Blazer. Or maybe she's getting revenge for 30 years of shop visits with that thing.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...