No crank/ no start....need some help!

Screan29 · June 20, 2020

As the title says I have a no crank/ no start on a 2016 Silverado. A million posts on it but nothing that is helping my situation. So take a seat this is gonna take a minute to explain.

This is an intermediate issue which normally occurs in the morning (dew) or when it rains. Everything is dry as can be expected under the hood. Another feature of this is when I do get it to run the engine signals will stop at the dash (no oil, temp, tach, or speedo) mileage also goes away and will stop registering while driving. Throttle becomes hesitant and engine feels like it is missing. It will then correct itself and repeat. I get all the service warnings when this comes up for 4wd, stabilitack, and so on) sometimes the ac will stop blowing cold and the power steering will fail during this time when the dash blanks out.

I have checked all grounds, positive cable connections, fuses and relays as well. I have no stored fault codes so I'm believing I have a power or short somewhere. When I have the no crank/ no start I have no communication at the OBD port. I have checked pin 6 and 14 during this and read 118 ohms. I replaced the two relays and immediately got a reading of 61 ohms! Truck started and ran fine (no rain though) came home and stabilitrak service message came up. Then the truck wouldn't crank/ start and it all started all over again. Trying to avoid the dealership but seems I am running out of options. Appreciate any advice, guidance, or help!

Steve

Edited July 5, 2020 by txab

rusty503 · June 20, 2020

Just about everything you list points to a ground issue. One big ground issue is corrosion build up INSIDE the ground cable usually at the battery. The cable may look great on the outside, but bad inside. Another clue you mentioned is moisture. Corrosion will affect an electrical system many many times worse than when dry. Another problem with the cable is bad crimps at the terminals. One ground point to check out are the ones at the forward left and right sides of the dash. I believe one is G218. I don't remember the other one. There are some videos on YouTube about them.

You really should trust me on this. I have seen these type of issues here many times and in all or at least most cases it was a ground issue. The other times it ended up being the battery.

Screan29 · June 20, 2020

Yeah replacing my ground is my next step. I've checked the g218 ground and the passenger side as well. Being as I have zero codes I have a hard time believing the ECM is intermittently failing. I have probably read every one of those posts lol. Watched every video making sure I wasn't skipping a step. Going to try and get s ground cable tomorrow and see what happens. Thanks for your feedback Rusty!

rusty503 · June 20, 2020

Get that battery checked first. Keep in mind that you might have an intermittent in the battery. Something else to try is shaking the ground cable when you are having the problems(no start). Sounds like you do have a good head start.

rusty503 · June 20, 2020

Some other thoughts here. The connectors under the fuse block in the engine bay may have corrosion and check the grounds for the ecm and bcm. Also check that the ecm and bcm connectors are fully seated. Maybe pull those connectors and check for corrosion then fully seat them.

Screan29 · June 22, 2020

So a little update on the issue. Battery is good. Installed a new battery ground. All connections have been cleaned, inspected, and treated to keep out moisture. Still no change. So this morning I had the same no crank / no start with no communication from the ECU. I decided to put in neutral and try. Truck fired right up. Happy and mad at the same time now. It's not just a start issue though as I still have the common loss while driving. I am hoping I have greatly narrowed my search. So far no obvious signs of external wiring damage so I guess I'm off to the dealer to see what their computer tells us. Interestingly when I am driving it the truck starts to sputter I can shift into neutral and it will immediately stop until back in drive...

Scot Evanson · June 29, 2020

hello

What was the outcome?

Screan29 · July 5, 2020

Went and saw a friend at the dealership and we played around trying to recreate the issue to see if he could pin point it. We had no luck. Even the dealer software could not find any stored codes that a scanner may not read. Of course when we drove it we got nothing as well! We even parked it in their carwash and soaked it to get as much moisture into it. He rechecked everything I did to settle his brain that it was indeed done. We determined it was certainly an electrical issue. I asked about the fuse block as we have an 07 that melted the connection under it but it wasn't acting like this one. He kept my truck over night and rigged up a jump out harness to the bottom of the fuse junction block so we would not disturb anything testing it as while removed it tested good. Low and behold it failed first try in the morning and the issue was the junction box ($157) to buy from the dealer. Super easy to do as long as you don't rush removing the connectors and break something. Have had it in for several days and rain storms without issue. Took the old block apart to inspect it and saw no visible damage. No signs or arcing or water intrusion. However the board in it is a two piece board with pins on both sides and all of the circuits sandwiched inside. Had a friend who builds boards split them without damaging so we could look inside and could certainly see water intrusion. The board has three well finished sides and one that is rough from where it looks like it is cut after. That rough side was were the water got in and damaged the circuits inside. Sucks you can't see it any other way. All in all was an easy repair once we were able to isolate it. Total cost was just over $200 as I replaced my ground in the beginning that had some corrosion. My friend told me it costs around $500 to do it at the dealer. Part plus 3 hours of labor in case you don't want to try and just let them do it.

Edited July 5, 2020 by Screan29

Sl16den · September 30, 2023

Is this the main fuse box on the drivers side under the hose you’re referring to as the junction box? And do you mean the top portion with the handles that pops off with all the fuses in it?

fascar2000 · October 30, 2023

Anyone have more details on this? I'm having this issue on my 2015 2500hd. I search for junction box and find no parts. The crazy thing is mine will start with the remote and not give any issues after. If we put it neutral sometimes it starts and sometimes it doesn't. When it doesn't start we put it back in park turn off and remove the key. Try again and it fires up. Any help on this junction box would be appreciated.

TIA