How do you test the DME for problems?

[deliriousga]

I'm at my wits' end with trying to figure out the throttle problem so I'm wondering if the DME itself is messing up. Is there a way for me to test it or do I have to give up and go to a dealer?

I think I've done everything else I can to try and remedy the problem. The E-Gas throttle will not go over 2K rpm and gives me the code P1502. If I clear the code, the car runs beautifully until you turn off the engine and restart it. That's the case whether the engine is cold, warm or hot. I have checked for vacuum leaks and replaced the MAF, O2 sensors, fuel pump relay and throttle body. I don't know what else could cause this problem and go away when the code is cleared unless it's a problem with the DME.

TIA! :cheers:

[Loren]

P1502 Throttle Jacking Unit, Spring Test – Above Limit

The position of the throttle is controlled by a digital position controller which emits a pulse-width-modulated (PWM) duty cycle and a direction bit.

After the output stage has been deactivated, the throttle is brought into emergency air position by means of two springs. This return of the throttle must take place within a certain time. If this time is exceeded, a fault is stored in the memory.

P1502 Throttle return time too long. – Throttle part

Diagnosis Procedure

1. Replace throttle part.

2. Erase the fault memory.

3. Perform adaptation.

End

Perform adaptation. (you will need a PST2 or PIWIS for this)

1. Switch on the ignition.

2. Wait one minute. Do not press the accelerator.

3. Switch off the ignition for at least 10 seconds.

4. Read out the fault memory.

[deliriousga]

Perform adaptation. (you will need a PST2 or PIWIS for this)

1. Switch on the ignition.

2. Wait one minute. Do not press the accelerator.

3. Switch off the ignition for at least 10 seconds.

4. Read out the fault memory.

I thought the adaptation mentioned in Bentley manual did not mention the PST2. Does the reading of the fault memory with the PST2 finish the adaptation? It would be wonderful if I could just take it down to my local guy and have him do this.

Sorry to get bogged down in this, but I'm curious about how the PST2 works. I have an OBDII reader and was looking at the Durametric Porsche reader. My OBDII reader will only read the DME when the car is running but the above instructions look like you read the DME with the car off. Can the PST2 read the DME when it's off or just turned to the "on" position without starting the car or does it have to be running?

Thanks! :cheers:

Edited July 25, 2006 by deliriousga

[Loren]

You need the PST2 to check for fault codes and to verify that the throttle is reading 80% at full throttle.

The Durametric software can give you those same readings.

[deliriousga]

You need the PST2 to check for fault codes and to verify that the throttle is reading 80% at full throttle.

The Durametric software can give you those same readings.

When I pull it up with my OBDII reader and watch the real time stats, the throttle position stays flat at 5.19% at idle and when the pedal is all the way down. The MAF rate is flat in all positions too, never changes. Once I clear the codes, everything runs normally, but at full throttle the throttle position is 100%. Is that something that can be cured by plugging in a PST2 instead of the OBDII?

After this, I was thinking there may be a problem with the throttle position sensor, but since it's E-gas, I think that is built in to the throttle body that I just replaced, but I'm not sure about that. In the Bentley manual they don't really cover the E-gas very much. Does anyone know if there is a separate throttle position sensor on the eGas model?

TIA! :cheers:

Edited July 26, 2006 by deliriousga

[Loren]

The Durametric mateched the PST2 in my tests.

Was this the problem you had before replacing the throttle body?

Did you do it or did a shop use the old throttle sensor on the new throttle body?

[deliriousga]

Was this the problem you had before replacing the throttle body?

Did you do it or did a shop use the old throttle sensor on the new throttle body?

Yes, the problem started before the throttle body was replaced. I had to replace the turn signal switch so the battery was disconnected to do that. When I reconnected the battery and went through the calibration sequence, the throttle would not go above 2400rpm. Since then I cleaned the old throttle body and did the other part replacements to try and remedy the problem, but it won't go away.

I was wondering if the Durametric was worth the money since I already have the OBDII reader. From your post, being able to read the computer settings before starting the engine, it looks like it may be worth a try.

Edited July 27, 2006 by deliriousga

[Loren]

Almost sounds like an intermittent wire or connection since sometimes it works.

I wonder if the pedal sensor is bad?

The Durametric Software can read and reset codes for ABS, PSM, AC/Heating, Airbags, Tiptronic, Seat memory, etc. It can read but not reset alarm codes.

I don't know of any other tool that can do that besides a used PST2 ($2000-$4000 on eBay) or a PIWIS $18,000 at your dealer.

[deliriousga]

Almost sounds like an intermittent wire or connection since sometimes it works.

I wonder if the pedal sensor is bad?

The Durametric Software can read and reset codes for ABS, PSM, AC/Heating, Airbags, Tiptronic, Seat memory, etc. It can read but not reset alarm codes.

I don't know of any other tool that can do that besides a used PST2 ($2000-$4000 on eBay) or a PIWIS $18,000 at your dealer.

Thanks for all of the great info Loren. Someone with a VW with E-gas had a similar problem and said cleaning the pedal assembly and sensor fixed it so I think I will try that then get the Durametric hook up if it still gives me trouble.

Thanks again for the help! :cheers:

[borisboem]

Hi guy, hope u are still member here, cause its an old discussion here. I have exactly same problem with my boxster S, 2000. Replaced MAF and throttle body. The car is running ok in emergency program when i disconnect MAF, so the pedal sensor must be good, but for the rest is the same as your situation.

I am wondering, how did u finally find out and fixed it??

Thanks

Boris

I'm at my wits' end with trying to figure out the throttle problem so I'm wondering if the DME itself is messing up. Is there a way for me to test it or do I have to give up and go to a dealer?

I think I've done everything else I can to try and remedy the problem. The E-Gas throttle will not go over 2K rpm and gives me the code P1502. If I clear the code, the car runs beautifully until you turn off the engine and restart it. That's the case whether the engine is cold, warm or hot. I have checked for vacuum leaks and replaced the MAF, O2 sensors, fuel pump relay and throttle body. I don't know what else could cause this problem and go away when the code is cleared unless it's a problem with the DME.

TIA! :cheers: