Ecu
 

I got a used ecu. The person i hot it from said it was for a manual quattro which is what i have. I swapped it out and the the check engine light comes on and the car idles at 400 rpm almost stalling constantly. Its the same part number and everything. Whats the problem?

Try a throttle body adaptation first. If that diesnt help, do the Vagcom ECU recoding procedure in the DIY section.

I tried the TB adaption today. I guess Ill try the vagcom ecu recoding but I gotta find a vagcom first. Thanks.


edit: Are there any free versions of VAG-COM ? If so can they recode? I need to do this so I can send ECU out for tune. Thanks.

Yes, you can download a shareware version that'll do plenty from Ross-Tech: Home. Just have to get a cable from eBay and you're in business. Use the search feature and look for "throttle adaptation" and you'll find a method to do the TBA with the key.

So I got the free version and did that recode procedure. Turns out the code for the ECU was identical to my original ECU code. So that wasnt the problem. I tried the TB relearn by putting car on Key on engine off mode several times for several minutes with no results. Same problem. So my car has check engine light, barely stays running at like 3-400 rpms while violently shaking. Maybe I just got screwed and bought a faulty ECU? Any other ideas?

Did you disconnect the battery for an hour or so before trying the TBA? If not, you didn't actually cause it to adjust, you only primed the fuel pump.

Nah the one I read didnt say to do that I dont think. However its been unplugged for 1.5 hours and I just attempted it again. No luck. Still 400 rpm idle, trying to stall, shaking like crazy, smell of gas. Then switch to normal ecu and everything goes back to normal. I got the ecu from a member on this site should I try to return it?