"Service Trailer brake" Warning in DIC

[morley8065]

Has anyone else had this warning pop up in their DIC," service trailer brake"...has happened twice now, once on a snowy day, the other on a dry day...

[gmtech4]

you have a problem with your TBCM system ,,,,,,take it in for warranty ,it doesnt matter if others have seen it ,,,,

 

Trailer Brake Controls Description and Operation

Some trucks less than 3900 Kg (8600 lb) GVW with a gasoline engine may be equipped
with a Trailer Brake Control Module (TBCM) or a combination Fuel Pump/Trailer Brake
Control Module (FTCM) system for electric trailer brakes. Some trucks greater than
or equal to 3900 Kg (8600 lb) GVW may be equipped with a integrated Trailer Brake
Control Module (TBCM) system for electric trailer brakes. The power output to
the trailer brakes is based on the amount of brake pressure being applied in the vehicle’s
brake system. The available power output to the trailer brakes can be adjusted to
a wide range of trailering situations.

The integrated trailer brake uses the master cylinder pressure (provided via Controller
Area Network (CAN bus) from the Electronic Brake Control Module (EBCM)) and the brake
switch signal (hardwired) to determine trailer braking. The user gain allows the driver
to adjust the amount of trailer brake output to match the trailer load and road surface.
The controller determines the desired trailer brake output and provides a control
signal
to the solid state relay. The solid state relay amplifies the signal and provides
the output required to activate electric trailer brakes.

Note:
Connecting a trailer that is not compatible with the trailer brake system may result
in reduced or complete loss of trailer braking. There may be an increase in stopping
distance or trailer instability which could result in personal injury or damage to
your vehicle, trailer, or other property. An aftermarket controller may be available
for use with trailers with surge, air or electric-over-hydraulic trailer brake
systems. To determine the type of brakes on your trailer and the availability of controllers,
check with your trailer manufacturer or dealer. Do not power-up an aftermarket controller
with the factory brake controller at the same time.

The vehicle is equipped with the following trailer braking components:

• Manual Trailer Brake Apply
• Trailer Gain Adjustment
• Trailer Brake Control Panel
• Trailer Brake Driver Information Center Display

The Trailer Brake Control Module (TBCM) or a combination Fuel Pump/Trailer Brake Control
Module (FTCM) can support up to a maximum of 4 axles with electric trailer brakes
(8 brake magnets).

Manual Trailer Brake Apply

The Manual Trailer Brake Apply Lever is located on the Trailer Brake Control Panel,
and is used to apply the trailer’s electric brakes independent of your vehicle’s brakes.
This lever is used in the Trailer Gain Adjustment Procedure to properly adjust the
power output to the trailer brakes. Sliding the lever to the left will apply only
the trailer brakes. The power output to the trailer is indicated in the Trailer Brake
Display Page in
the Driver Information Center. If your vehicle’s service brakes are applied while
using the Manual Trailer Brake Apply Lever, the trailer output power will be the greater
of the two.

The trailer and the vehicle's brake lamps will come on when either vehicle braking
or manual trailer brakes are applied.

Trailer Gain Adjustment

Trailer Gain should be set for a specific trailering condition, and must be adjusted
any time vehicle loading, trailer loading or road surface conditions change.

Setting the Trailer Gain properly is needed for the best trailer stopping performance.
A trailer that is over-gained may result in locked trailer brakes. A trailer that
is under-gained may result in not enough trailer braking. Both of these conditions
may result in poorer stopping and stability of the vehicle and trailer.

After the electrical connection is made to a trailer equipped with electric brakes,
the TRAILER CONNECTED message will be momentarily displayed on the Driver Information
Center. The Trailer Brake Display Page will appear on the Driver Information Center
showing TRAILER GAIN and OUTPUT, after all vehicle related service messages are acknowledged
by the driver. The dashed lines in the TRAILER OUTPUT display signifies a disconnected
trailer
or trailer brake fault condition, and will disappear only when the fault condition
is not present.

Trailer Gain Adjustment

• Adjust trailer gain in 0.5 step increments up to 10 gain setting by using the gain
  adjustment +/- buttons on the trailer brake control panel switch. Pressing and holding
  a gain button will cause the trailer gain to continuously increment or decrement.
  To turn the output to the trailer off, set the gain to zero.
• Drive the tow vehicle and trailer combination on a level road surface representative
  of the towing condition, and free of traffic at approximately 32–40 km/h (20–25 mph)
  and fully apply the manual trailer brake apply lever mechanism located on the trailer
  brake control panel switch. Adjusting trailer gain at slower speeds may result in
  an incorrect gain setting.
• Adjust the trailer gain to just below the threshold of trailer wheel lock-up. Important
  trailer wheel lock-up may not occur if towing a heavily loaded trailer. In this case,
  adjust the trailer gain to the highest allowable setting for the towing condition.

Trailer Brake Control Panel

Important:
Re-adjust trailer gain any time tow vehicle and trailer loading or road surface conditions
change or if you notice trailer wheel lock-up at any time while you are towing.

The trailer brake system has a control panel with the trailer gain and manual apply
switches, and is located on the instrument panel to the left of the steering column.
See Instrument Panel Overview for more information on location. The control panel
and switches allows you to adjust the amount of output, referred to as trailer gain,
available to the electric trailer brakes and allows you to manually apply the trailer
brakes. The Trailer
Brake Control Panel, and switches is used along with the Trailer Brake Display Page
on the Driver Information Center to adjust and display power output to the trailer
brakes.

Hill Start Assist and Trailer Sway Control

Hill Start Assist

The hill start assist allows the driver to launch the vehicle without a roll back
while the driver is moving there foot from the brake pedal to the accelerator pedal,
refer to Hill Start Assist in
ABS Description and Operation.

Trailer Sway Control

The trailer sway control can detect the vehicle yaw instability, caused by an attached
trailer, refer to Trailer Sway Control in
ABS Description and Operation.

Driver Information Indicators and Messages

The following indicators are used to inform the driver of several different factors.

TRAILER CONNECTED

This message will be briefly displayed when a trailer with electric brakes is first
connected to the vehicle. This message will automatically turn off in about ten seconds.
The driver can also acknowledge this message before it automatically turns off.

CHECK TRAILER WIRING and TRAILER NOT CONNECTED

This message will be displayed if:

• The system detects a trailer with electric brakes is connected to the vehicle, and
  then the trailer harness becomes disconnected from the vehicle. If a trailer connection
  is made initially and the vehicle or trailer wiring connections is not correct the
  TRAILER NOT CONNECTED message will be displayed during the ignition key up as if there
  is no trailer connected.
• The trailer connection is recognized initially and then a disconnect occurs while
  the vehicle is stationary, this message will automatically turn off in about thirty
  seconds. This message will also turn off if the driver acknowledges this message off
  or if the trailer harness is reconnected.
• A disconnect of the trailer wiring harness occurs while the vehicle is moving, the
  CHECK TRAILER WIRING message will continue until the ignition is turned off. This
  message will also turn off if the driver acknowledges this message off or if the trailer
  harness is re-connected or repairs are completed.
• There is an electrical fault in the wiring to the electric trailer brakes. The CHECK
  TRAILER WIRING message will continue as long as there is an electrical fault in the
  trailer wiring. This message will also turn off if the driver acknowledges this message
  off.
• A poor connection at the 7–way connector may cause the CHECK TRAILER WIRING message.
  Some aftermarket 7-way trailer side connector adapters or plugs may cause deformation
  or excessive wear to the vehicles trailer terminals. It is recommended that you use
  an OEM or Pollak Heavy Duty 7-Way Trailer Side Connector Adapter.

SERVICE TRAILER BRAKE SYSTEM

This message will be displayed when there is a problem with the trailer brake control
system. If this message persists over multiple ignition cycles there is a concern
with the trailer brake system. Take your vehicle to an authorized GM dealer to have
the trailer brake system diagnosed and repaired.

TRAILER GAIN and OUTPUT Display

This display menu can be accessed by scrolling through the Driver Information Center
menu, or any time the trailer gain +/- button is depressed, or the manual trailer
brake apply lever is actuated. The trailer gain display is 0 to 10 in 0.5 step increments,
and indicates the current user setting of the trailer output gain. The trailer output
is 0 to 10 bars in 1 bar increments, and indicates the output power
provided to the trailer brakes, relative to the gain setting.

[Trwtow]

Has anyone else had this warning pop up in their DIC," service trailer brake"...has happened twice now, once on a snowy day, the other on a dry day...

well did you get it fixed

[morley8065]

Well of course. Gm decided to put a bad brake controller in my truck. Add that to the list of problems. .

[bboyce536]

Any one else having this issue? Yesterday was the 3rd or 4th time I've gotten this message. Very annoying as it doesn't go away, just keeps popping up.

[carlosh]

I had it happen one time but could not duplicate. Was COLD out when this happened as well.

[Brad Jenks]

Happened to me when I hooked my trailer up. I parked the trailer, did some work on it, and when I hooked it back up, the trailer brake unit was working. If it happens again, I'll take it in.

[c0ld29]

I had this happen driving during lunch. No unusual conditions. Then a couple days later it would chime every 10 seconds and throw up "SERVICE TRAILER BRAKE SYSTEM." Went away when I stopped at my destination and turned the truck off. I was worried that the dealer would see no warning and dismiss it. I have also never towed anything in this truck yet.

 

Dealer said that it was stored on the computer showing there was an issue and they "reflashed my trailer brake system" and the error went away. So far so good 1+ month out.

 

So if you had the issue (even if it went away) I'd recommend bringing it to the dealer or mentioning it during an oil change if the code does indeed get stored. Better safe than sorry.

[Blacksilveradoltz]

Thanks c0ld29 ( and everyone else) I have experienced the exact symptoms you have described and was going to call to see if the error was stored I willcal tomorrow to arrange to have it looked at as I want to test haul a travel trailer later this week...

[redwngr]

Did you check the trailer plug / truck plug for dirty connections?

[rleague81]

Just took mine in this morning for the same error. Apparently there is a bulletin out for it. Tech ordered a part and will have to take it back in when the part arrives

[Chevor]

Had the issue "Service Trailer Brake System" with no trailer connected on the the 2013 3500 with 31000 miles. Dealer replaced Master cylinder pressure switch under warranty. No issues now.

[soosick13]

I'm having this warning along with stabliltrack pop up on my dash at least once every time I drive it. I have taken it to the dealership and was told they couldn't replicate the problem so they didn't know what to do, I took it to a different dealer and they are saying its because the lift kit. and because I have a lift kit installed I voided my warranty and would have to pay to have it diagnosed then pay for any repairs. Its a 2015 with 11,500 miles on it.

[Jackseric]

I was driving from Florida to Ohio and mine did this same beeping and flash the warning every 10 seconds, too. Probably did it 3 or 4 separate times in a 3 hour window. Stopped the 2nd time to look for an issue but found none. Got home and passenger side tail light bulb was out. Maybe just coincidence, but it wasn't out when the message was happening. Truck was 6 months old and only had 10K miles on it. Just got around to mentioning it to the dealer this morning. I'll see what they tell me when I pick it up tomorrow.

[Jackseric]

OK, so I got my truck back from the dealer last night. They said there was a 'false code' in the system that had nothing to do with the trailer brake system, and all they could do was clear it. They added more dielectric grease to the trailer wiring terminal in an effort to make sure it wasn't water causing it. I don't know why because it was already covered and I told them it was bone dry when the error was happening. Eh, I hope it was a fluke and doesn't repeat itself, or was simply caused by the tail light bulb acting funny as it was about to burn out.