I want to start by saying that I just stumbled onto this forum last night, and this is all very new to me. About a month ago I had an o2 sensor short out in my b5 s4, and now have this code locked in two ecus (a revo stage 2, and a giac/awe stage 3):

 18042 - Accelerator Position Sensor 2 (G185): Signal too High
P1634 - 35-00 - -

Both ecus still run the car, but won't come out of limp mode. I replaced the o2 sensor, and bought another ecu. That fixed the issue, but now I have these two bad ecus. I took them apart and neither shows any physical damage. That brings me to the point of finding this forum. I was trying to save these ecus from going in the trash, but I am also wondering if the ecus are toast, can the software still be saved? My new ecu is another awe/giac stage 3 tune, but only has the pump program, and no boost controller. 

So I started playing tonight with the dead stage 3 ecu. I read the flash and saved it to tunerpro, I downloaded the xdf file for the ecu, but made no changes to the bin file. My first thought was maybe I could just re-write the flash to the ecu and the code would be gone. That was probably a silly thought, the ecu is just as it was before. It still runs in limp mode with the same code. I assume the revo box will do the same. But I now have the stage 3 bin file saved, and I also have a spare stock a-box on the shelf. I am wondering what all is actually in the bin file, if I write this file to my spare a-box will I have access to my boost controller? It seems that the giac flashloader must do something to modify the bin file itself to change settings, but there has to be something in the ecu to start with to allow these changes, as my current ecu doesn't have this feature.

What I am after here is, is there anything I can do to save these ecus, and is there any reason I shouldn't flash the stage 3 tune to my spare ecu? I would read and save the stock file from it before doing so as a "just in case", I just don't need another dead ecu on the shelf.

Thanks

The faults you have should be strictly related to the hardware. If you reflash the original tune from the bad ecu, it should work fine on another ecu without problems. I am in the process of getting familiar with the electrical repair of these types of ecu, so If you're interested in letting them go please let me know!

I played around a bit tonight. I saved the a-box flash and wrote it to the stage 3 box to start just to be sure that the throttle code was a harware issue. It is, as it was still present with the a-box flash in the ecu. I then put the stage 3 flash back into the ecu, and it still has the code, and still runs in limp mode.

Next I tried writing the stage 3 flash to the a-box, the flash seemed to write ok, it reads through vag-com as an m-box, and the giac flashloader recognizes it as a giac flash. I was able to set it to the pump program, and able to adjust the boost setting using the boost controller in the flash loader. The only problem is that the ecu will not run the car I don't know why for sure, it will crank, but not start. I thought this was strange because I was able to write the stage 3 flash over the a-box flash in the original stage 3 ecu and it still starts and runs the car. Any idea why this might be?

The revo flash seems to be untouchable, it will not read. Not that I really had intentions of ever going back to it anyways.

As for the hardware issue in the ecus, do you have any idea on a fix for this? Any idea what component gets damaged?

There is no serial eeprom on the s4 ecus, you should be able to write the a box without issues.  might try flash it with a stock m box bin first then the giac file you have. 

You may want to try and code out the error you get, i always wondered also if that will fix the issue with hardware, if you take the code out of the software.  if you want i can take a look at your computer see if i find any hardware issues.

Are you sure, this thread leads me to believe otherwise, it describes exactly what I am trying to do.

http://nefariousmotorsports.com/forum/index.php/topic,150.0.html

When the stage 3 tune is flashed to the a-box, there are no codes present. In vag-com and on the giac flashloader, everything looks to be correct, it just won't start.

I can't come up with any other explanation as to why I can flash both ecus with the a-box file, have them both run the car (the bad one in limp mode, but running), then when I flash the stage 3 file over the a-box file, only the bad ecu will run the car (again in limp mode).

As for the other two ecus I would prefer to repair the hardware issue inside them. I just need to figure out what needs to be changed and where to get it, hopefully it's something digikey will have. If anyone knows of a company, or individual that is able to repair these for a reasonable price, let me know.

I have been trying to find information on cloning ecus, but almost every thread suggests that to do so will require a special eprom burner. I was hoping to be able to do this with my vag cable. Anyone have any pointers either way? I would rather not spend $150 on the burner I will probably use one time. I could probably have awe add the features to my current ecu for that much.

It definately sounds like a hardware issue to me.  I saw this or something very close on a 1.8t jetta that had damaged o2 wiring.  I ended up adding an external ground at the ecm for testing and the car ran and had no faults.  It should be pretty easy to test and duplicate, as the fault indicates it was an internal ground in the ecm for the throttle position sensor or sensors (I can't recall exactly how it was wired).  Look at the ecm circuit board closer and trace back from those pins.

Cool, I downloaded the monoscan software today. I'll try it out this weekend.