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Any suggestions other than MAF?


egbert

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Hello everyone, great site.!

I bought my 2000 996tt a year ago with mods already on it including an ecu upgrade (approx 0.9bar max)and a "sports" air filter.

Everything ran fine for the first 10,000 miles although I suspected a dodgy MAF because of a slight hesitation in 1st gear on steady throttle, I had a minor accident and bashed into a kerb, when this happened the PSM failure and ABS failure lights flashed on.

The car went in to have some suspension components replaced and also a sensor on one of the brakes I think.

When I got the car back it started playing up in traffic on hot days, the abs failure and psm failure lights coming on as soon as the car reached a certain temperature.

I bought a replacement MAF and installed it and the problem stopped, however the car now throws the ABS and PSM lights on WOT in 6th at 4,600 rpm.

I went to porsche and complained about the MAF they sold me being faulty so they replaced it themselves free of charge.

Unfortunately the same thing happens again although slightly lower revs now, approx 4,200-4,300.

I decided to remove the air filter and replace it with a stock part and cleaned the MAF at the same time, unfortunately same result.

I got Porsche to run diagnostics which they did and found no fault, they also said it has 0.9 bar and that is why it's blowing MAF's, but it ran fine for 10k miles so I don't see that view as correct.

1) Is it possible that the accident has broken something to give me the error code 5525 torque transfer from DME disturbed at times.

2) Could the latest MAF have been "blown" by running with the oiled filter, will I get a different result if I change again?

Any advice gratefully received, it's a bit disconcerting to lose ABS and PSM when hitting high speeds, I just hate having something wrong with the car that I can't work out.

Sorry for the long post, I figured I should include as much detail as possible.

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  • Admin

Is this a UK car (where they report the manufacture year rather model year)? because the 996TT didn't come out until MY01.

Have you had the fault codes read on the car? The is the first thing you should do - and write them all down and report back here.

At this point it could be anything from an air/vacuum leak to a MAF to a bad electrical connection.

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Is this a UK car (where they report the manufacture year rather model year)? because the 996TT didn't come out until MY01.

Have you had the fault codes read on the car? The is the first thing you should do - and write them all down and report back here.

At this point it could be anything from an air/vacuum leak to a MAF to a bad electrical connection.

the vehicle delivered date showing in the book is 01-09-2000, strange, it is a German car imported to the UK.

The fault code that came out of the Porsche computer was

PSM fault memory

1 fault

5525 Torque transfer from DME disturbed at times.

Many thanks for your help.

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Every fault has a code PSM, ABS, DME etc., etc.

You really need to these codes to narrow down the possibilities.

the code I listed above is the only one on the sheet they printed out for me when the light was on.

PSM fault memory 5525 Torque transfer from DME disturbed at times.

Thanks again for the help.

Edited by egbert
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  • 2 weeks later...

I had the error messages again, always the same, around 4.5k revs in 6th gear, this time it was only about 1/4 throttle though.

I got the abs and psm failure lights and drove straight to Porsche and had them plug in the computer.

P0103 HOT FILM MAF SENSOR

5525 TORQUE TRANSFER FROM DME DISTURBED AT TIMES

2 different errors they said, the MAF one was shown as an intermittent fault and not present ie was not faulty sitting in the shop at that time, the 5525 fault however was shown as present.

I know it just looks like a plain MAF failure but I've replaced it twice now and the problem isn't going away, the car ran fine for 10k miles without blowing a MAF so there's no reason why it should keep pinging them now.

I'm worried about this torque transfer error message, they said they'd never seen it before at the dealer.

Anyone have any ideas?

much appreciated.

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  • Admin

The 5525 code can be caused by a a faulty PSM/ABS - which can be caused by a bad MAF.

If you were to unplug the MAF and drive the car it is common to have both the PSM and ABS lights come on - and then to get a torque transfer error from the DME.

Since you have replaced the MAF (twice now) I think I would start looking a MAF wiring and connectors. If these all test as good and are not intermittent then the problem could be a bad DME.

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The 5525 code can be caused by a a faulty PSM/ABS - which can be caused by a bad MAF.

If you were to unplug the MAF and drive the car it is common to have both the PSM and ABS lights come on - and then to get a torque transfer error from the DME.

Since you have replaced the MAF (twice now) I think I would start looking a MAF wiring and connectors. If these all test as good and are not intermittent then the problem could be a bad DME.

hhmm, bad dme sounds expensive, I'll take it to a rolling road so they can replicate the problem, hopefully another MAF will sort it.

thanks for all your help, I'll let you know any results.

:renntech:

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  • 2 weeks later...

I'm taking the car to a specialist tomorrow and he's confident he can solve the proble.

Interestingly I ran the car on Sunoco GT race fuel yesterday (105 octane very high O2 content) and I couldn't get it to throw the error messages, the car didn't feel particularly quick on the race fuel (quick enough to pull 10-15 car lengths on a 997S 0-150 and go past an Audi RS4 from behind in 5th gear roll on, although I would expect at least that under normal conditions)

So no error messages with race fuel despite going WOT in 6th several times.

As soon as I refilled with BP 97 octane fuel the car felt smoother but threw the error light straight away at 4.2k rpm in 6th.

:huh:

Edited by egbert
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  • 4 weeks later...

P0103 Possible fault cause

1. Intake air system on pressure side (between turbocharger and engine) leaks

2. Short circuit to B+

3. Mass air flow sensor faulty

4. Throttle jacking unit faulty

Diagnosis/Troubleshooting

1. Check intake air system for leaks.

2. Check wiring from MAF sensor to DME control module for short to B+.

3. Check signal from MAF sensor.

4. Check and clean throttle jacking unit.

5. Clean air cleaner and replace filter element.

Edited by Zippy
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P0103 Possible fault cause

1. Intake air system on pressure side (between turbocharger and engine) leaks

2. Short circuit to B+

3. Mass air flow sensor faulty

4. Throttle jacking unit faulty

Diagnosis/Troubleshooting

1. Check intake air system for leaks.

2. Check wiring from MAF sensor to DME control module for short to B+.

3. Check signal from MAF sensor.

4. Check and clean throttle jacking unit.

5. Clean air cleaner and replace filter element.

Thanks for that Zippy-the car had several boost leaks but the problem remains unresolved-throttle jacking unit sounds interesting though. Basically all wiring has been checked and we now need to look at the DME to see if there is any corruption.

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sounds really frustrating but really intriguing! PLEASE keep us informed as these types of faults are of great interest.

I had a car 01 turbo that would only achieve .4 bar boost and have had a devil of a time with it. :cursing:

Thanks for that Zippy-the car had several boost leaks but the problem remains unresolved-throttle jacking unit sounds interesting though. Basically all wiring has been checked and we now need to look at the DME to see if there is any corruption.

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  • 1 month later...

still no solution but seems like we're getting there.

The ECU was removed and cleared and a standard map put on it and the car didn't have any error messages.

Once any modified map was put on the ECU it threw the error message again.

Apparently this means the ECU is shot (although i don't understand why it should work with a standard map but not any modified ones)

I'm having a new ECU built with the modified map in place, hopefully that will cure it.

If anyone has had similar experience or can give some insight I'd be very grateful.

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  • 1 month later...
Just to finish the story off, new ECU fitted and problem solved, corrupt ECU the cause.
Did they try re-programming the DME before they replaced it? or did they just replace it?

They tried to reprogram it but the problem had started getting worse with error messages in 4th 5th and 6th at 4.6k rpm and apparently they had trouble trying to replace the file on the unit. (if that makes any sense) My understanding of it was that the corruption had got so bad that it was impossible to access the ECU and manipulate the map in the normal fashion.

They had returned the ECU to a standard map on an earlier visit and said it cured the problem which is how we isolated the ECU as the problem. Why it would run OK on a standard map but not on a modified one I'm not sure.

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  • 2 years later...

What is the throttle jacking unit do, and where is it?

P0103 Possible fault cause

1. Intake air system on pressure side (between turbocharger and engine) leaks

2. Short circuit to B+

3. Mass air flow sensor faulty

4. Throttle jacking unit faulty

Diagnosis/Troubleshooting

1. Check intake air system for leaks.

2. Check wiring from MAF sensor to DME control module for short to B+.

3. Check signal from MAF sensor.

4. Check and clean throttle jacking unit.

5. Clean air cleaner and replace filter element.

Thanks for that Zippy-the car had several boost leaks but the problem remains unresolved-throttle jacking unit sounds interesting though. Basically all wiring has been checked and we now need to look at the DME to see if there is any corruption.

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