Well I made a comment on another post saying I came up with a fix for the psm failure issue when running the 997 gt3 brake master cylinder. Well I have got a few messages so I will share here.

The theory was that when going to the gt3 master, the larger piston would produce to much flow and trigger a pressure switch inside the psm pump and cause it to trigger a psm and abs failure. This failure would happen for some constant and others intermittent. It would happen less if running the larger 997tt/gr3 rear caliper with larger pistons but would still happen.

So my ideas was to just slightly reduce the pressure and it would fix the problem. We created a test unit and put it on Dan kinzie's car. Dan has run it for over a month as well as 2 full track days and I can confirm it fixed the psm issue.

We setup a jegs brake proportioning valve inline and maxed the pressure on the valve, then backed of just a tiny bit. Only takes about a 5% or less reduction to not trigger the psm failure.

This is something that you can do yourself if you have brake line flaring and bender tools I will be making up a few kits for guys that want to go to a gt3 master but not have the resources to make the lines.

It's simple but works. Any more question, feel free to ask.

 

Awesome, I probably will never go to 380s but I know this is a big deal for those who have, nice work!

 

This can be used with the stock brakes. Going to the gt3 master is to improve pedal feel. When going to the 997 gt3/turbo calipers though it is better due to the larger piston in the rear calipers of those requiring more fluid flow.

 

My brakes are 100% stock and all OE, never replaced pads or rotors. I started getting the ABS/PSM failure warning periodically shortly after removing the front diff, axles and cardon shaft. I drove about 10 miles to my shop, aired up my tires as they were a bit low, no more warnings. I think it may have been coincidental? But maybe not. If tire diameters are a bit off I think it could trigger this. My car sometimes sits up to 2 weeks without being driven, especially in a heavy snow year. Often, I may get the warning a hundred yards or so after leaving home and not having driven the car for a few days. If I turn off the key and do a restart repeatedly after getting the warning maybe 4-6 times, I generally won't get it again as long as I'm driving the car regularly. I'm most certain it's not a brake related issue or a MAF issue as some have mentioned.

Any ideas what may be causing my ABS/PSM fail warning?

 

Been fighting this issue for years after adding the GT3 large bore master, I'm going to for sure give this a try, has anyone else already done it ?? Thank you for this fix, I know a LOT of guys like myself just bypassed the pump instead, but really nice to have the PSM actually work again for sure

 

So what is the kit for the ones that have been dealing with this for some time ? I have all psm off to avoid the problem that I couldn’t find any solution.

 

I just installed a 997gt3 mc and the "fix kit" at the same time. The pedal is significantly improved with the new master. No errors or problems. Heading to the track this weekend, so I'll be back with more impressions. So far, really happy with this upgrade. Thanks Freddy and dan!

 

Please keep us posted, soon as I can get to it I'm going to do mine, thanks....does the psm seem to function Ok with it installed ?

 

I'm not sure how to test out psm on the street, when its 42 degrees and I'm driving around on r compounds... I can tell you I can lock up abs, the brakes feel firm and work well. No errors on the dash. When I get some heat into the tires this weekend, I'll have a lot more to say I'm sure.

 

lol, yeah I can see that, I use my snow covered driveway up here, at 10*F and summer tires you can see real fast if its working or not

 

I believe that the car needs to be traveling at over 30mph, without using the brakes and the PSM does a self check. This is where the error code appears.

 

So I got on the track today at the glen. First half of the day, it was snowing. However it warmed up and the sun came out. My impressions are mixed. The feel of my brake pedal with the 997gt3 master is much improved, however psm seems to interfere in neutral throttle corners often. I eventually just turned it off and felt much happier that way. Overall I was a bit slower today on new r compounds than last year, but it's cold... tomorrow looks like rain/snow so I'll try again in May.

 

Thank you for the input, i've always shut it off on track, but as long as it worked without throwing a PSM/abs light and code the fix must work.... I just would like it to function on the street in slippery conditions and NOT throw the codes and shut off the abs every few miles. Like most right now I just leave the pump unhooked

 

So after some more time on track I think my tires were not at a good pressure. Weather has been **** so it's hard to dial in. Overall I'm rally happy now that I've had some more time on track.

 

I've had the same mid corner, neutral throttle PSM interference a number of times and while its a bit scary, every time it seems like touching up tire pressures solves it. Glad you found it so quickly, its crazy how sensitive the PSM is.