I have a 07 freightliner columbia, my tractor abs light just came on and is solid, and two error codes are now showing on the dash (abs 136 and ecu 128 ). Also, when braking for stop signs or red lights ive been losing 25-75 psi of air without using over 20psi to break. Took my truck to a shop and they couldn't figure it out, and im a new o/o so I figured id get more help from this group.