2017 Denali..Service Trailer Brake System

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Blackcar

Full Access Member
Joined
Mar 31, 2018
Posts
640
Reaction score
528
Today after filling fuel tank started up truck drove a little ways and Service Trailer Brake System? Haven't use system and truck only has 14000 mile 2017 Denali.
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,104
Reaction score
25,039
Location
Treasure Coast, Florida
Today after filling fuel tank started up truck drove a little ways and Service Trailer Brake System? Haven't use system and truck only has 14000 mile 2017 Denali.

Still under warranty? Check the connector next to the hitch, you can unplug it from underneath and clean out all the dirt/dust. If you have an advanced scan tool, you can pull up the code that triggered the message. Somewhere underneath is the solid state relay (SSR) and trailer brake control module (TBCM) which interact with the BCM, ECM and EBCM (brakes). Check the connectors on those if you can find them. On my generation, they were not where the manuals said they would be. The SSR turned out to be in front of the fuel tank and the TBCM mounted on the driver's side frame rail.
 
OP
OP
Blackcar

Blackcar

Full Access Member
Joined
Mar 31, 2018
Posts
640
Reaction score
528
Still under warranty? Check the connector next to the hitch, you can unplug it from underneath and clean out all the dirt/dust. If you have an advanced scan tool, you can pull up the code that triggered the message. Somewhere underneath is the solid state relay (SSR) and trailer brake control module (TBCM) which interact with the BCM, ECM and EBCM (brakes). Check the connectors on those if you can find them. On my generation, they were not where the manuals said they would be. The SSR turned out to be in front of the fuel tank and the TBCM mounted on the driver's side frame rail.
Went to dealer battery voltage low they replaced battery haven't seen message since. Two year old battery !
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,104
Reaction score
25,039
Location
Treasure Coast, Florida
Went to dealer battery voltage low they replaced battery haven't seen message since. Two year old battery !

It happens, and when they start to go bad they can wreak havoc on the electrical system setting off all kinds of false alarms. Mine is just over three years old and has been a little low lately too. Have a coupon for a new one...
 
Joined
Apr 10, 2017
Posts
37
Reaction score
8
2015 Denali here. I was getting the alarm on remote starts and periodic harassment on the Service Trailer Brake System. The final straw was that it wouldn't start after sitting for a week.

I replaced the battery. The alarm issue is gone. It's been a week. I had one STBS message right after but haven't seen it since. It seemed to do it more when it was wet out.
 

gsd1019

TYF Newbie
Joined
Sep 30, 2017
Posts
12
Reaction score
5
These trucks have an enormous parasitic load on the battery when parked. Battery tender all the way!
 
Joined
Apr 10, 2017
Posts
37
Reaction score
8
The battery didn’t fix my issue.

I’m about to go on a road trip this weekend. I didn’t bring it in to get repaired yet.
Every now and then - I get harassed with the warning. I get the warning ding and then the error clears - but this repeats every 30-60 seconds. It happened towards the end of my NY to NJ drive and didn’t not stop. Luckily it was 15 min from the destination. Today it started happening on my way home from work - good thing it was 5 min away. I’m crossing my fingers that it doesn’t happen on my 5 hour trip to Vermont.


Are there any temporary work arounds? Can I pull a fuse or disable it somehow?
 

JML07denali

Full Access Member
Joined
Mar 23, 2014
Posts
863
Reaction score
353
What was the outcome on this?


Sent from my iPhone using Tapatalk
 
Joined
Apr 10, 2017
Posts
37
Reaction score
8
In my case, nothing.

I took it to my mechanic. I believe a control module should be replaced to fix, but it would be expensive. They saw something about taking it apart, blowing out all debris and putting dielectric grease in. They tried it. It didn't seem to help right away. Then the issue stopped. I haven't seen this warning for the longest time.

Except I go and tow a trailer the other day. Now I'm getting this warning every now and then.

I'm thinking it may have something to do with the electric hookup by the trailer hitch.
 

lbenson

Member
Joined
Mar 4, 2021
Posts
76
Reaction score
53
I had a similar or same issue a couple years back... constantly alerting me on a 1200 mile road trip to service trailer brake controller. I honestly cannot remember if we ever fixed it or not... but the quote was like $1000 something to replace the faulty electronic causing it. Either way it happened again briefly a few weeks back and haven't seen it since.
 

Forum statistics

Threads
128,801
Posts
1,805,623
Members
91,784
Latest member
navyboy14094
Top