2016 Sierra Denali intermittently losing ABS/Power Steering and showing a host of error messages

[PirateToast]

About a month ago I drove my 2016 GMC Sierra Denali with about 70K miles on it in some snowy weather and had the following error messages appear:

 

• Service Stabilitrak
• Service Suspension System
• Service Trailer Brake System
• Steering Assist is Reduced Drive with Care

 

When this occurs the power steering and ABS will sometimes go out.  If I turn the truck off, then on again, it usually resolves the issue.  However, this issue seems like it can occur at anytime while driving.

 

I brought it into the dealership and they've tried a few things already:

 

• Replaced the battery
• Replaced the fuse block assembly
• Replaced the BCM

 

However, the issue is still occurring.  I know these issues that can't be replicated are tough to troubleshoot, but I can't have this truck going out on me on long drives.  It feels like a ticking time bomb.  It seems more likely to occur in snowy/wet conditions, but can't say that with certainty.  I also remember it first occurring shortly after someone closed the hitch a bit strongly.  Maybe there's some sort of wiring that could have been impacted towards the hitch that could be impacted by

[Chris Duesing]

Hi. I just finished dealing with a no crank issue on my 2015 Denali (6.2). As part of my diag I went to unplug / plug back in several fuses, relay, and wiring harness connectors.

 

My issue was ice blockage in the starter solenoid, however, when I got the truck running and cleared all the loss of communication codes, I was still having issues and messages exactly like you are describing.

 

I managed to bugger up one of the wiring harness connectors with the lever lock. I checked it 15 times and declared it good but was still having issues. I squeezed it together with my hand and poof, everything came back.

 

I swore it was seated properly but it wasn't. It's still cold out and I just came in to warm up. I'll get back out later and take a picture for you. But the connector on my truck that was the offender is on the driver's side, to the front and passenger side of the main fuse box under the hood. The plastic lever latch broke and blocked the connector from fully seating. I put wire ties on it for now.

[Chris Duesing]

[PirateToast]

Interesting. I'll have to try pinching that together when it comes on again. The message I'm seeing only goes away if I turn the car off/on again. So it might not be the same thing, but worth a shot.

 

It doesn't seem cold related, more like water/traction related. Water and an electrical issue kind of makes sense.

[sk]

Search these forums for "G218 ground" or "PIT5405" to see what to check.

[Sikk50]

I recently went through a similar issue.  Kept happening when my wife was driving which was conserning.  Ended up having to flat bed it to the stealer.  in the end they determined it was from my battery ground wire not pulling a proper voltage.  Replaced the wire and haven't had a recurrance

 

[DeePa]

I just went through having to clean where my negative cable bolts to the frame. Passenger side wheel well. You can see it and clean it without removing the fender well. 
 

the other part grounds above the starter. You do need to pull the fender liner to see it. 

[PirateToast]

A few updates and thoughts:

1. The wiring harness connector idea Chris had isn't applicable here.  My errors don't go away ever during driving, they only *might* disappear if I turn the car off/on.
2. The G218 and PIT5405 don't seem applicable to this year/make/model.
3. The battery ground wire, I'm not sure if that would've been replaced already or not, they did replace the entire fuse block assembly.  I could try this. 
4. The negative cable bolts to the frame sounds promising, I'd like more information on what exactly was done here. 

The issue recurred 3-4 times in the couples weeks since my second time at the dealer.  Yesterday it occurred and wouldn't clear, I had to drive without power steering in a few inches of snow to drop it off at the dealer for a third time.  Not fun!

 

The issue is far more prevalent in uneven terrain/bad traction/wet conditions.  It seems to happen frequently in 4 HI or on dirt, snowy roads in recent snowfalls. 

 

It's incredibly frustrating, I bought a truck so I'd have something that can handle these conditions.  Nothing scarier than driving a fish tailing, few ton, hunk of steel down the road without antilock brakes or power steering.

 

Any other ideas? 

[DeePa]

I told you what to do. The battery negative cable runs down the firewall to two places. One is above the starter on the engine block. The other is the passenger front tire on the cab side of the frame. Make sure these are clean of frame wax and rust. Mine had some insulation near the terminal between the metal and the frame. It’s a 10mm bolt. You can’t miss it. You do not need to remove the fender liner. You can take a few torx out to make it easier. 

[DeePa]

If you pull the mudflap and a few torx bolts on the fender liner you can pull it out of the way and see the ground. 

[Diverjer]

On 1/2/2022 at 3:14 PM, Chris Duesing said:

I was kind of wondering if my radio issue might be one of these blocks.  I notice the one you wired tied still has the red lock that suppose to hold things down, still must not have been enough.  I notice like mine that back block has lost the red lock.  I thought about wire tying the back one, but it seem tight.  Maybe the back ones never came with a lock tab like that front one?