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another question for B&B. "service brake system"

Discussion in 'Truck & Equipment Repair' started by CEPropertyMgt, Jul 18, 2008.

  1. CEPropertyMgt

    CEPropertyMgt Junior Member
    from N/A
    Messages: 12

    B&B

    at start up, the diplay on the dash says " Service Brake System", brake light on dash illuminiated as well as the abs light. brake fluid level is ok. will disappear with one or two restarts. Truck is an 04 Silverado crew cab, 2500HD, 6.0, Auto, 4WD.

    i have heard different things like bad ground for ecm located under drivers door area, reflash of ecm, weak starting battery, etc.. figured i would ask a pro

    ....
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Two of your ideas are on the right track since many times this issue is created due to the ABS module seeing a low voltage condition.. There was a TSB for loose cable connections for this issue at one time.

    The chassis grounds under the driver door and a defective battery or battery connection will, and are very well known for causing this exact issue. But another very common thing is a failing front wheel speed sensor.

    The grounds are easy, check and/or clean them up and see if the problem reappears.

    Same with the battery connections. But be sure to actually pry the terminals out of the plastic housing/insulator and check in there for corrosion too.

    And like I mentioned, a defective battery itself will cause this problem as well. If the battery is original on this '04...don't mess around, replace it. The Delco batteries are nowhere near what they used to be years ago and will make these trucks do all types of strange things when they're defective.

    No real way to test the front sensors without a scan for ABS codes. And even then you may not find any since this is a "glitch" as far as the ABS module would interpret it. Either have to spend the money to have it scanned, or replace them both as the last resort (not super expensive though). But start with the connections/terminals and see where your at.
     
  3. CEPropertyMgt

    CEPropertyMgt Junior Member
    from N/A
    Messages: 12

    thanks for the info B&B

    yes, it is still the OE battery. I will replace. I will also check the ground. this issue has only happened about 3 or 4 times this year. i will also check all the connections for corrosion.

    someone had told me it could be a glitch with the abs module and my brake controller on start up. could that cause the issue?

    thank you again for your help
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Thats a very common symptom...the fact that it only does it on occasion.

    If the controller was incorrectly wired would be the only way it could affect the ABS module. So if the brake controller works correctly, I'd say it's fine. :)
     
  5. larryhd

    larryhd Senior Member
    from vermont
    Messages: 213

    Abs

    I have same problem after I put a new 200 amp alternator in my 03 2500 HD.
    I wish I could get it fixed
    thanks
    larry
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If you've already been through the checks I posted for CEP Larry, then your condition may be a sometimes inherent characteristic of running the aftermarket hi-amp alt's in these later GM trucks. Some seem to work perfect after swapping one in, and others create some minor issues or glitches in the on-board systems (just like yours).

    And its due to the fact that the hi-amp aftermarket alts "ramp up" the charging current too slow after an engine start. So basically what happens is the ABS modules "see's" this as a low voltage condition...and there's no real fix for it- just the nature of the beast per say.

    What brand (or who's) alt is it?