Motor Vehicle Maintenance & Repair Asked by SteveRacer on September 25, 2021
All the dash warning lights are on (ABS, VSA, Power Steering) as well as messages displayed on the information screen.
hydraulic pump runs continuously, even with the car turned off.
Brake reservoir has proper fluid level, battery was tested fine (disconnected to prevent pump from draining battery)
Car is well maintained and under 50k miles.
I rapped the pump body with a hammer a few times, and the buzzing/whirring changed tone slightly. I’m suspecting the pump pistons are jammed in the rotor and the pump is not effective.
ABS does not function, but steering and all other systems run and drive normally.
Replacing the ABS pump/modulator is easy, but selling my firstborn for the part will not be.
On edit:
ABS pump is running continuously, even with the vehicle completely turned off. My Solus and code reader(s) don’t cover 2012 Honda for ABS. The controller seems to be part of the pump/modulator assembly. I suppose it’s possible it’s bad, but the internet searches seem to all point to replacing the pump.
The fact that I rapped it with a hammer and the tone changed (from a whine to a pulsing chug) leads me to believe the pump pistons no longer float well (probably from water/corrosion) and the pump is not effective in building accumulator pressure.
I found a 27k used one complete on eBay for $110, which is half of what I can buy just the controller for. The pump section can be taken apart (not officially) but I’m waiting for the spare installed and working before I break that seal.
Car is functional without ABS but would be stranded with the modulator removed and all the brake lines open. The Vehicle Stability Assist, ABS, and in some way the electric power steering are all somehow tied to this pump/modulator module.
Replacement of the pump/modulator assembly solved the issue.
Replacement was straightforward, although it was tight getting it out without damaging (bending/kinking) the four wheel brake lines, as these are plumbed into the top of the unit making extraction difficult.
Bleeding was NOT easy, and I had to resort to old-school shadetree methods. Luckily, there was still plenty of snow and ice patches in local parking lots, which enabled full exercise of the ABS and VSA systems. Several pattern bleeds and redneck driving back to the local slippery spots cleared the system. My SnapOn Solus would not talk to such a new system for a controlled pump bleed. (But in all fairness I haven't spent the thousands necessary for Domestic/European/Asian updates that would make this possible.)
eBay was a great source for this part, from a reputable "salvage/wrecker". The cost was almost a tenth of the Dealer List, which was around $1200...
Problem solved; customer very happy.
I still have no idea what the power steering system interaction is with this system to create this combined fault. The yellow traction control, brake, and steering icons were lit in the cluster, along with the red BRAKE icon. They all went away instantly after pump assembly replacement, without any "clearing" with a diagnostic tool. The BRAKE warning appeared later after testing, but the information display claimed "Low Brake Fluid" which was legitimate after overzealous bleeding.
Correct answer by SteveRacer on September 25, 2021
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