Jump to content

Service Brake System Message...

Mark Francois
 Share

Recommended Posts

Mark Francois Enthusiast

Mark Francois

Posted
Posted

I've been getting an intermittent Service Brake System Message along with the ABS light and Parking Brake warning light on my 2003 GMC Yukon 2wd with the 4.8l motor. Sometimes it will be days or a week or two between getting the message or maybe one day to the next but they always clear up after I drive a little, stop and restart the truck,. Sometimes it is as quick as just driving just a couple hundred feet and restarting the truck or it may be when I reach my destination. I'm hoping that it is just an intermittent failure from one of the front ABS sensor but is there a way to check the sensors out with a multimeter to make certain that it is them or just a way to trouble shoot the system in general. It is kind of a tough one since it is an intermittent issue. Thanks in advance!

 

IMG_2606[3350].jpg

makingterrificdecisions New Member

makingterrificdecisions

Posted
Posted

I've got simlilar message. Service brake booster. Read up on it and it could be many things including:

- replace brake booster or vacuum pump (wasn't for a silverado though)

- poor contact of the sensor due to rust/corrosion

I can't remember the last one, but best to take it to a mechanic because it seems pretty random

 

  • Like 1
davester Senior Enthusiast

davester

Posted
Posted

It's also common for the ground connection to be a problem for the abs computer.  It's located on the wing, just off the frame under the driver's seat.  Unbolt the wires from the wing, clean the connectors and the wing, bolt them back down and smear some dielectric grease over them.

  • Like 1
Mark Francois Enthusiast

Mark Francois

Posted
  • Author
Posted (edited)

Thanks guys, I'm guessing that you mean these two grounds attached to the body mount perch under the drivers footwell just behind the front wheelwell? If so, I'll clean them up and put some DI grease on them this weekend.

 

IMG_2628.jpg

Edited by Mark Francois
added picture
Mark Francois Enthusiast

Mark Francois

Posted
  • Author
Posted
18 hours ago, davester said:

Yup, those are the ones.

Cool deal! I’ll try what you suggested this weekend. Thanks. 

Mark Francois Enthusiast

Mark Francois

Posted
  • Author
Posted (edited)

Well, the grounds were not the issue so I got off my lazy butt and tested the sensors themselves. What I found was that the passenger side sensor output was half the voltage (AC) of the drivers side. I belive that testing the sensor with a multimeter on AC while spining the tire is the proper way to check function. I know that the rate in which I spun each wheel was not exact betwen the two but it wasnt so much of a difference that the voltage should differ by half. What do you guys think? Something else I noticed while troubleshooting this issue is that when not in alarm, unplugging the drivers side sensor only illuminated the abs light but when unplugging the passenger side sensor tripped the abs and brake icons in the dash. Is this the intent to help mechanics differentiate between faulty sides or am I seeing something else and don’t realize it?

Edited by Mark Francois
  • 2 weeks later...
Mark Francois Enthusiast

Mark Francois

Posted
  • Author
Posted

Well, changing out the front two abs wheel sensors didn't fix the issue. At first it seemed right but then it lot up again then it was off and then it was on again lol I didnt mind the work it took to swap those out but dang I’m tired of this intermittent problem garbage!  

  • 2 months later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • newdude
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By newdude · Posted

      No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      
    • jaszr2
      Active Grille Delete

      By jaszr2 · Posted

      Hello from Australia Just sharing that there is now a way to delete the active shutters entirely with just a plug in module. Opens up tons of room to light bars etc.
    • jake111
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By jake111 · Posted

      I have an observation and a question... 1) I watch the voltage closely because I have had to dial in the cut-in/cut-out voltages of the battery separator to my camper.  The "smart" charging drives me nuts.  Anyway, I noticed that when coasting for a while, and especially if lightly using the brakes (though not necessary), the voltage goes up from mid/high-13 volts to mid/high-14 volts.  Then it drops back down after stopping or going again.  Consistently!   The only explanation I can come up with is REGENERATIVE BRAKING!  Well, maybe that's a little bit of an exaggeration, but it's certainly free extra battery charging.   2) Driving on mountain roads I will use L and vary the max gear.  Things straighten out and I end up in L10.  Sometimes I leave it there for a while.  Is there any difference between L10 and D?   
    • devonthegreat
      anyone interested in a 2002 Chevy Silverado 4x4 parts truck NYC

      By devonthegreat · Posted

      **SOLD** Please end or delete post. thank you
    • PBNB
      Tire pressure for 37s

      By PBNB · Posted

      Do you think this width might affect the chalk test with a higher pressure closer to 65psi? I think lowering the pressure makes sense to get the tread to lay flatter

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...