My car will usually throw the ABS/PSM error message on the gauge cluster... happens under WOT in 4th or higher gear. Restarting the car will reset the error and dash warning lights. When error light is on, there's no change in power or performance, though I do not know if ABS is still active.

I am not venting to atm; re-routed my SSBOV just this afternoon to vent back into intake. Boost is only about 1.1 BAR with upgraded turbos and Upsolute II programming. MAF was replaced 2 wks ago at dealership.

Here's the kicker... ECU has neither stored nor pending error codes when I scan it.

Is there a secondary place where error codes may be stored? Anyone ever experience this? How can I have something seemingly as impt as an ABS/PSM failure warning, and yet nothing stored in the ECU?

Thanks.

 

My guess is if you're not getting a CEL, it probably won't store a code. When you are getting this on WOT, more than likely you have a intake leak maybe somewhere past the MAF sensor.
That's it for my armchair troubleshooting for ya!

 

BTW, here's my theory pertaining to why I'm experiencing the ABS/PSM failure.

I've re-routed my SSBOV to vent back to intake, and despite this, I'm still experiencing the ABS/PSM error. New MAF was installed couple weeks ago.

Here's my theory...

FACT:
- I can only boost about 1.1~1.2 BAR before overboost fail-safe kicks in.
- MAF limit appear to be set at 425, at which point the datalog for MAF flatlines.
- Others run 1.3~1.4 BAR with no issues.

It is my suspicion that my ABS/PSM error is triggered when the 425 limit is reached/exceeded. We'll call this MAF-triggered failsafe. And if it is exceeded by too much OR if it's exceeded too often, then the failsafe kicks in.

The failsafe can be triggered by numerous conditions, two of which I suspect is:
- BOOST-triggered: boost too high
- MAF-triggered: MAF limit exceeded

My theory is that my MAF limit is set too low, which would explain everything. It would explain why I can't run the higher boost that others can. It'd also explain why dialing down the wastegate will curb the errors and failsafes.

I'm looking into setting my MAF limits closer to the flow that would be experienced at the BOOST-triggered failsafe (as opposed to MAF-triggered failsafe).

In other words, let' say that the BOOST-triggered failsafe is at 1.4BAR, which produces a MAF flow = 450. Therefore, the MAF limit should also be set to 450, so that the two triggers are along similar lines. You guys following?

 

As one considering the same mods to my '03 x50 that you have made to your '01, Stephen, your working these bugs out is of great interest. Please continue to post your experience.

 

I get the PSM / ABS failure at cold engine startup and not revving above 3000. Do not have diagnostic tool, so can't read codes. Upon restart, PSM / ABS lights do not illuminate. WTF is this all about?

 

I had the same problems at Watkins Glen a couple of weeks ago. I have yet to get the codes read but the service manager at Princeton Porsche said he felt it was an ABS sensor. With the ABS not working the PSM can't do its job so they illuminate together. He also said that if you start the car a couple of times between the lights coming on and reading the codes that no code may be stored. Have you been able to check for codes when the problem occurs? I too would be very interested in hearing how to resolve this.

 

I have been datalogging at the exact moment that the error occurs... and nothing shows up in the ECU. It has been brought to my attention that each individual electronic control component stores it's own fault codes (dme, abs, etc). So, the next time the weather is nice, I'll go out and try to trigger the code, and drive straight to the dealership.

But, again, I suspect that this may have less to do with that and more to do with reaching the MAF limits of the programming in my case. We'll see... still researching...

 

I think you should just keep it simple and see what happens. Check for leaks and reroute you BOV discharge to the ATM.

I've re-routed my SSBOV to vent back to intake, and despite this, I'm still experiencing the ABS/PSM error.

I think that's what is causing your problem.

 

I can vouche for both of these points. My 01 Turbo would throw ABS/PSM failure lights, and unless you drive it right to the dealer and don't shut it off, there won't be codes to read. And on mine it was the harness leading to the left front sensor that ultimately was the cause.

BTW, just so you know, you have NO ABS when the failure lights are on--it is designed to shut down ABS and PSM when there's the slightest interruption in the ABS and PSM circuit.

Had three brake lockups at three different track events while my dealer was trying to find and fix the fault.

And I swear the brakes where more finicky. I wasn't into the ABS at the moment the light went off, but did have rear wheel brakes lock all three times, when the warning light came on during hard threshhold braking.

 

Thanks... I will look into this... the only problem I see with this theory is that my ABS/PSM error ONLY comes on when I'm WOT in the higher gears... which doesn't make sense...

 

My first question is did you have the same problem before the MAF was replaced? If not I would suspect a defective MAF. If you unplug the MAF and run the car in the speed density mode you get the same lights. When the MAF reaches the upper limits the car defalts to speed density mode using the o2's and MAP sensor to adjust fuel ratios.

Having the MAF values max out should not trigger ABS/PSM lights. Some tuners of other marques have struggled with this same problem on Bosch equipted cars. GIAC has the problem solved on that as well as the 1.2 bar limit before throttle cut.

Alas there are other solutions. Once you determin that it is the MAF limit triggering the ABS/PSM light you can make a larger MAF housing and rescale the sensor using this little device (http://www.splitsec.com/products/psc1/PSC1003.htm). When making a larger MAF housing try to go up in small increments say 10%-15% for starters. You can then apply the same correctional percentage to the PSC1 to get you in the ball park.

FWIW I would consider using the GIAC software. Garrett has LOTS of experance tuning Bosch equipted cars. He has a mobile tuner software suite for Audi that allows you to fine tune your car with a laptop. I have to assume that the same will soon follow for the P cars.

 

Problem existed before and after MAF swap. Basically, doesn't appear to be MAF related.

Are the GIAC boys the only ones running 1.3~1.4 consistantly?

FACTS:
- 996T can boost 1.3~1.4 BAR with proper setup... GIAC has proven this
- Kevin II turbos which I have can easily handle those levels, and all the way up through ~1.8BAR while within it's efficiency maps
- Upsolute II software is currently tuned for ~1.1BAR

I'm trying to work with Upsolute for them to crank my boost limits to ~1.3BAR. While certainly do-able, I don't know if I can convince them. I really do hope so, as my experience with them has been very positive thus far. If not, I very well may have to go with a different programmer, as you've suggested, to obtain 1.3BAR.

 

Good luck!!!

I would like to see upsolute do well in their tuning venture. My 2 cents is don't waste another mile low boosting and jump ship. Garrett is sooo far ahead in his Bosch motronic knowledge. Your upsolute ECU is best left for someone with lesser turbos.

 

I have UpSolute and EVO DVs. The only time that I throw the ABS/PSM is when I'm coasting in 5th gear and have some 'need' to go WOT. I haven't done this for a while but I think that it still happens even after the remapping by UpSolute, although less often. It never happens in 3rd or 4th gear.

 

How do I get Garrett or Protomotive or any of those guys together with my car/turbo... THAT, is the question. Cause I certainly don't feel like shipping my car out to Cali... and as far as I know, they've never worked with Kevin II turbos... (they are fully capable of programming my setup, but to do so, my car and the programmer would have to be in the same place.)