2017 Denali unsolved problem

Jerry Lee · March 21, 2019

Sometimes I can get in my 2017 Denali pickup with 28,000 miles and put the ignition switch in the start position and nothing happens. The dash lights go out but the headlights don’t even dim. The headlights are on because the truck is inside the garage. This usually only happens after the truck has sat for a day and night or longer. The battery voltage remains above 12 volts. The local parts house checked the battery and it shows to be good. After I get it started by connecting a battery charger at 50 amps it does fine the rest of the day. I have cleaned the battery cables twice, moved the battery cables around while the ignition is in the start position with no luck. Since this seldom happens, the dealer can’t find the problem. It happened again this morning and I tried the remote start and the engine started right up. Later, I noticed the volt meter was reading lower than usual but returned to 14 volts after restarting the engine. Any one want to make an educated guess of what might fix it? Thanks

1SLOW1500 · March 21, 2019

When it doesnt start the is a soft code report. Dealer knows this but never seam to tell customers. There are some tsb that state batter cable issues. Also remember there is a ground strap to the firewall. When you said test good does that mean it was load tested or just voltage tested? Big difference. I would also have the alternator tested but again if the truck isn't telling the alternator to up output then there is your issue. Once mine did that as the truck sat for 2 weeks. When it started I looked at the gauage at it read 15.2v so the alternator is trying to charge up that battery. All day every time I stopped the engine it wouldn't restart. Buy the afternoon battery was back and I was good to go. But as I rarely drive the truck I have 2 batteries and a isolator. So I can push a button and start the truck any time I like.

Nitrousbird · March 22, 2019

The fact the truck wouldn't start this morning via key but did via remote start tells us several important things - it isn't the battery, grounding, alternator or battery connections. Otherwise, it would have had the same issue via remote start.

I'm leaning toward the key cylinder or something related to the keyed ignition.

Jerry Lee · March 22, 2019

I think you may be right. It did it again this morning and started with remote start. It’s getting to do it more often and maybe the dealer can see it happen then locate the problem. Like you said, probably the ignition switch. Thanks