jckol

I need to replace my abs pump / module to repair my return pump fault. Can I purchase a module out of any 996 or does the part number have to match exactly? I see many on eBay ranging from various prices, from as low as 25 to 1800, with part numbers varying by a digit or 2 at the very end. Picture of my pump for reference. I have a 2000 c2. Part number on the pump is 996.355.755.46

Also, is there any coding required when changing the pump / module?

pdxmotorhead

Coupes and 2wd Targas should be one part, then you have C4/GT/Turbo with and without PSM,
Just to not make your life suck I'd find one from the same year and model. With same antilock system.

zbomb

I matched the PN exactly. Yes, I saw a bunch of variants and no, I was not willing to chance it with all of them being a bunch of money and the install being a pain in the ***.

hbdunn

Who diagnosed this? You said with the PSM pump disconnected you still had ABS correct?

If you are getting the 4460 code I'd try a proportioning valve on the secondary circuit. This code sometimes happen with a GT3 MC on a C2.

jckol

Zbomb, did you have to code yours when you replaced it?

I diagnosed it. The wiring is all fine. Master is oem. The abs light used to come on under hard braking at the track. Now it is on all the time. I clear the code, go for a drive, when I turn the car off and back on abs light comes on for return pump failure. Same situation when the actual return pump is unplugged.

Code is 4266.

zbomb

No, I did not recode and your symptoms seem to mirror mine.

jckol

what did you swap? Just the abs block or the whole unit with the block and the module on the side?

zbomb

Whole unit.

hbdunn

This does sound like what zbomb had. ABS module failure. Was hoping for you it wasn’t.

De Jeeper

Do u have psm? If not a mk1, c2, nonpsm is about the cheapest one out there.

meirschwartz

I had an intermediate abs light coming on for a long time, that turned into permanent.
Duramatric was reading different codes every time, and sometimes not communicating with the module at all.
I got a used part of eBay with the same part number just in case.
I didn’t want to mess with the hydraulic lines, so I thought I will start with replace only the module.
it’s a bit difficult to get to one of the screws, but not as involving as replacing the whole unit and bleeding the system.
it solved my problem and the replacement module did not required any programming.
my car is 02 C2 no PSM.

jckol

I do have PSM, although, I not not against deleting it if it involves saving 1000+ dollars. I see boxster units as cheap as $25 on eBay lol. For that price I almost want to try it, but it's a headache to install / bleed the brakes after.

meirschwartz

so do what I did and replace only the module. Worst case you lost $25 and one hour of your life 😁.
the aluminum block is a set of mechanical valves. I find it hard to see how they can go bad (although possible).
in my case the ABS light came on even without driving the car, which lead me to understand the issue was electrical and not mechanical.
although I don’t have any experience with the PSM i still think replacing the module worth a try.

jckol

Yea I think it might be worth a shot I am just not sure if that will have the same coding / function as mine. But again for $25-$60 it’s worth trying.

when I originally bled my brakes the fluid was green, maybe it was the abs module falling apart internally? Who knows.

De Jeeper

Or it was deluted Ate blue fluid. They dont sell it anymore but i still see it in cars occasionally.