Location of ABS computer in an '01?
 

I'm scavenging the ABS parts out of a crashed '01, intending to transplant them into my ABS-less 99. I got most of the bits I need today, but couldn't find the ABS computer. The 99/00 PDF claims it's behind the glovebox, but the only thing I saw there was the anti-theft module, so they musta moved it for the 01+. Does anyone know where it is or, even better, have a picture of it?

Also, the Mazdaspeed parts diagrams claim the booster is different for ABS and non-ABS cars. Any idea why? I didn't pull it off the wrecked car yet because the nuts are a PITA to get to and it looks the same as the one on my 99.

--Ian

On the '01 and later cars, the ABS computer is built into the ABS pump / valve assembly under the hood. It's all one big unit which Mazda calls the HU/CM (Hydraulic Unit / Control Module.)

As for the booster, I'm not 100% certain. I know that the master cylinder itself is a bit different on ABS vs non-ABS cars to accommodate the different plumbing, and the ABS cars didn't use a discrete proportioning valve, however I can't find anything which definitely explains why the vacuum booster itself has a different part number. (For what it's worth, the non-ABS cars even had two different boosters depending on which suspension package they received.)

Ah ha! That would explain why there are fifty zillion wires in the ABS pump wiring connector, which seemed like it was more than would have been necessary if it was just the hydraulic bit.

The Mazdaspeed parts diagrams identify three vacuum boosters for the 01:

N066-43-800A: Vacuum Power Assist (normal suspension w/o ABS)
N067-43-800A: Vacuum Power Assist (hard suspension w/o ABS)
N069-43-800: Vacuum Power Assist (ABS)

Bizarre that the booster would be different for the sport suspension.

thanks
--Ian

Ah, you got your response in there before I was done editing. :D (I had to go over to another computer, as I didn't have all of the catalogs on the laptop.)

This integrated design for the ABS system seems to be the norm these days. I know Subaru does the same thing, probably most other manufacturers as well. Definitely advantageous from a manufacturing standpoint (fewer parts, less wiring), not so much from an out-of-warranty customer saying "I have to pay you HOW much for a new ABS module?" perspective.

Ya that big stupid cadmium-plated ish looking thing on the passenger side. The size of a horse.

Yeah, for a car where ABS is optional I can certainly see how combining them would make manufacturing cheaper.

I'm kinda surprised manufacturers don't combine it with the main ECU, it seems like that would be cheaper if you have a vehicle that has ABS standard like most do these days. I was kinda worried that's what had happened on the 01.

--Ian

This!

http://www.codrus.com/abs/pump.jpg

--Ian

I wonder if the booster and or master cylinders have different part numbers because of what gets relocated in the engine bay for the different configs. On the 99/00 cars I believe the Hard suspension got the shock tower brace. ABS requires the washer fluid bottle, and possibly other things, to be moved around. Etc.