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Thread: 07 Sierra E-brake & Abs after gear swap.

  1. #1
    Advanced Tuner
    Join Date
    Jun 2014
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    216

    07 Sierra E-brake & Abs after gear swap.

    Yet again another E-brake & Abs after gear swap problem. I did a lot of research and tried several combinations but came up with nothing. This is an 07 sierra with LS3 swap. Rebuilt the rear end and swapped to 3.90 gears. Originally thinking it had 3.42s but software shows 3.373s previously programmed. Going to check the old gears tomorrow.

    Truck does not have a rear speed sensor. There's no machining on the axle housing for the sensor and the plug has a factory weather sealed cap on it.

    Can't view abs codes through hptuners and going to scan it with a tech2 tomorrow at work to see anymore details of the code.

    I tried the self calibration for speedo and shift point correction. Read many post how it changes more figures than it needs to.
    Tried the setup from hptuners own calibration
    Tried shift points only setting VSS out put pulses original and final drive ratio original at 3.73
    Tried shift points and VSS out put pulses changed by hptuners self calibration and final drive ratio 3.73
    Tried shift points and final drive ratios 3.90 from hptuners own calibration and set the VSS out put pulses back original and still no fix.

    Assuming since there's no rear speed sensor then the abs is using the front 2 wheels and transmission output speed to check itself.
    Any suggestion out there before I find out more details from the Tech2 tomorrow.
    Last edited by Nastruck; 08-27-2014 at 07:14 PM.
    04 Single cab Lq4/243 228r 112lsa, Long tubes, catless, Yank st3000.

  2. #2
    Advanced Tuner
    Join Date
    Jun 2014
    Posts
    216
    So scanned it and I don't remember code number off the top of my head but its set cause the rear speed sensor is more than 25% different than the front. Front two sensors were the same. Rear sensor is off 5-8mph at 70mph.

    Truck not having rear speed sensor in the rear end I assume its using the transmission speed sensor. So guess I still need to find the right vss out put pulse per mile.
    04 Single cab Lq4/243 228r 112lsa, Long tubes, catless, Yank st3000.