How do you test the DME for problems? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

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!

deliriousga, have you posted your question with the PCA Tech web-site? Try sending an e-mail to the Boxster expert there; Scott Slauson. His address is [email removed] Good luck!

Hi, I haven't looked into your problem, no time this week. But, the basic tenet of dealing with ECU's is to disconnect the Battery to reset it. Disconnect for 5 min. (Radio Code in Hand), then reconnect. You'll experience some rough idling and performance for the 1st 15-20 min. until you complete a drive cycle, but this just may clear things up. Hope this helps... Happy Motoring!... Jim'99

Sorry Jim, I didn't mention I tried this too. Thanks for the suggestion, though.

Does your OBDII reader have a software that lets you monitor things in real time? I don't have a good idea what may be wrong in your case, but you might be able to confirm that for example your e-gas controlled throttle opens up wide enough to go above 2000rpm. Also, you could monitor your O2 sensors and the MAF air flow rate right when you try to go above 2000rpm - maybe that would give you a hint at what's wrong. Hope you find it! Gary

It does record real time stats. I was watching it yesterday when I first started it before I cleared the codes. When it is running poorly, the throttle position reads 5.19% at idle and when the pedal is all the way down. The MAF rate is flat in all positions too, never changes. 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. I will have to pull up my PET program at home and see what's in there. Any other suggestions out there? TIA!!

That sounds like you have found the culprit right there. The e-gas does not recognize that you push down the throttle; it always leaves the throttle at the same position (idle), hence the identical flow rates from the MAF. I think that the e-gas has a component right at/under the gas pedal that is responsible for converting your gas pedal movement into electronic (digital?) data that is then sent to the throttle body. The throttle itself only reacts to the data, not the actual action of your foot on the pedal. So I would bet that in your case the component at the gas pedal is broken. Hope this helps... Gary

I had a similar problem on a e-gas VW. The DME wouldn't complete the throttle body adaptation cycle. I removed the gas pedal assembly and took it apart. Inside it's just a big potentiometer, used some contact cleaner on it, reassembled and it worked fine again. You might want to give this a try, you can also remove the cover on the throttlebody pot and clean it in the same manner.

I will give the gas pedal cleaning a try. I cleaned out the throttle body and then replaced it when that didn't work. Thanks for the info.