blueline

I had PSM and ABS lights come on today during hard driving. I stopped and restarted the car, which cleared these codes, but I got them again the first time I got on the boost hard, but this time I also got a solid on CEL. THe CEL won't reset when I restart the car. I'm not having any other symptoms. The car is still running strong.

I have read other threads about CELs on 996 TTs but nothing matches exactly.

Here is the background:
The car is a late year 2001 TT w/ 7000 miles. I bought the car in September with 3800 miles on the clock. I had the Upsolute ECU upgrade done after a couple of months. Once after the upgrade, I had the PSM and ABS lights come on, but it never repeated until today. About 4 weeks ago, I had my dealer replace the plugs w/ FR6s, and install new EVO diverter valves.

I'm in Charleston SC for Christmas, and plan to drive the car home (about 250 miles) in 3 days. Should I be concerned about driving the car home with the CEL on? I plan on taking it in to my dealer to have it checked out when I get back. Any advice is appreciated.

ebaker

Stop at a Pep boys or Autozone and get the code read. I'd take a wild guess that it has something to do with the work recently done, maybe a loose vacuum line.

Oak

PSM ABS CEL sounds like a maf issue. suggest a simple cleaning may do the trick. so you have an aftermarket intake or filter?

Oak

I recall someone mentioning there was an issue with Upsolute programming and colder temps on 01's. That could be the problem. Give Ups a call.

blueline

No aftermarket filter or intake. I remember seeing a thread about cleaning the MAF. Does anyone have a photo of where this is in the engine compartment?

PorschePhD

My guess is it is the parameter for the maf. Were you WOT or in a upper gear full throttle? This is when it happens. It actually is a program issue and throws a 55525 code which is a data transfer issue. It comes up TQ difference communication error. It will tell you to replace the ECU. The program can not read the difference between the MAF and the denser air. The colder the air is the denser it becomes. Colder air carries more 02.

Have the code read first then see what it says. If you drop me an IM or email with the numbers I can diagnosis this from afar for you.

blueline

Stephen - I think you may be on to it. I was WOT in 6th over 100MPH the first time, and the 2nd time too. I will try to get the codes read before I drive home. I'm also going to see if I can pull off an MAF cleaning. Thanks everyone for all the help. What a nice thing it is to get experienced advice even on a holiday weekend.

PorschePhD

Certainly sounds like the issue. Keep us posted.

tkerrmd

Ok just when I thought Upsolute was OK, now what??

dmilzoff

No, I don't think that it's a problem with Upsolute exactly. I think that the programming does reduce the latitude outside of the acceptable range for the sensor reading though.
I've had my Upsolute now for over 2 years, 20,000 miles. I have had the same lights (twice) but both times the Dealer changed my Maf sensor. It's been OK for 8000 miles now with 2 track events.
I would never remove the Upsolute program. It's great.

PS. I just read that CRC now has a new spray cleaner specifically for MAF sensor cleaning!

PorschePhD

There are several reasons why this happens. It doe not occur in all cars and it is a specfic issue with the software. If you datalog the MAF you will see if the MAF is bad or the program rolled out of range. Again, some do it and some do not.

blueline

I got the car into the local dealer in Charleston today. The short answer is that several hoses associated with the turbos were found loose or improperly assembled. This is possibly a result of having my DVs replaced. I'll take this up with my regular Porsche dealer this week.

Here is what the tech said:

"Found Fault codes P1250 and P0103. P1250 = Boost pressure control exceeds limit value. Possible cause, turbocharger faulty, or bypass flaps incorrectly adjusted. P0103 = Mass Air Flow above limit. Possible cause intake leak on pressure side of turbo between charger and engine. Opened Engine Compartment, and found the pressure pipe from intercooler to engine not engaged completely. Raised car and found same condition on inlet to intercooler. Also found pipe into the turbo from air distributor not assembled with marks lined up, and the hose clamp was cocked. Reassembled all pipes correctly and checked for tightness. OK. Erased faults and drove car under boost conditions with no fault recurrence at this time. Vehicle tests OK at this time."

Total cost - $121.72 which I thought was quite fair.

I drove the car home, about 250 miles on low congestion Interstate. No repeat of any lights. The funny thing was that I couldn't produce over .5 Bar of boost until I stopped to refuel. After that, boost easily reached .9 on demand. I still want to clean the MAF sensor, and have everything checked out. I think I will take it in for an explanation and check over.

Thanks for everyone who helped out. I love this board!

Chris