I have been having problems with a motoronic number 4Z7907551AA ME 7.1.1 installed in a 2004 audi a6 2.7t. I don't know who to turn to as I cannot receive solid testing information.

I had my ecu sent into to a company to have it flashed with a remapped fuel and boost curve. They returned it, the car ran for two days and would no longer fire. It cranks only. I have fuel delivery. The only code the ecu is reporting is P0601. I sent the ecu back to them, the said they reflashed it. It was returned to yield the exact same results. They told me to purchase another ecu which I did. They programmed it and the same results are now happening with the second ecu. Same code report.

I am now purchasing a third ecu but I would like to know if there is anything that can produce this code or otherwise destroy the ecu so that the car will not run. I do not want to install a third ecu and have something destroy this ecu as well. Up until now I have been assuming the non-starting condition is a result of their flash job solely based on the single code. To add; it is not an immobilizer issue because there is no code report and the car does not start for a second and shut off while flashing the immo light....it simply just cranks with no fire whatsoever.

An internet search yields posts about performance tuning creating this response but I want to be 99% sure before plugging in the third ecu. I plan to check voltages and resistance for grounds at the ecu connector once I review the pinouts. I have no where else to turn that has enough knowledge to provide legitimate recommendations. I hope you can help. Thank you for your time.

That's actually good to hear. I was hoping it wasn't something in the car exterior to the ecu that was causing it. It's lengthy, but I'll give you the rundown.

I sent my ecu into apr to have a stage 1 tune. I felt fairly good about it because they seem to be a reputable company and tune many cars. Got the ecu back, installed. Car ran for about 30 minutes total (within a driving period of about two days). Went to a restaurant, ran fine on the way there, came out and nothing...just cranks away no fire. Checked every fuse I could find, checked to find fuel at rail squirting out when cranking. Popped in my cheap obd2 and see p0601. Did a search on google, found that is not uncommon for older apr tunes mainly on GTI i think. So I send it back the first time. They send it back to me, said they fixed it (mind you, never telling me what they've actually done to resolve the problem), and same exact results.

They then tell me, with a bs excuse, (I will cut and paste the actual cop-out in a bit) that basically the ecu was already bad and the actually pulling out and reinstalling it made it find the error by scanning default maps it hadn't seen in years....don't ask me, just what they said. So ultimately it was my responsibility, if I wanted my car running to source an ecu (bought identical one on ebay for $200) and sent both the original and newly acquired ecu to them. They said they took immo data off original installed it on new ecu and sent both back. Now the new one did the same exact thing, same code, just cranks no start. SO....out of curiosity I installed the original that was supposed to be stock now and it started the car but wouldn't run because of immo not programmed. So I told them all of this and they said send both in again. I did, they returned and now both original and new are the same...completely dead with the p0601 code. Furthermore, they said that because I didn’t plug in the used ecu that I bought for them to program, that is was most likely already defective too.

Now completely irate, I call and yell a bit and they ultimately tell me to buy an ecu from audi....holy sh1t was I mad! After a day of calling around I call a local audi dealer, they said buy a used one and we should be able to code it for 550, or let us get an oem and we will do everything for 1900. My response was, "yeah, right; on a 8000 car that I paid someone to damage"...

Status as of right now: I bought another used one on ebay for $200. I wasn’t going to send them this one. I was going to learn a little bit here first and see what I could figure out on my own. They said to send the first two back to them, I got them to say they would purchase a new ecu from the local audi dealer near them. Supposedly, they said worst case scenario I would be responsible for yet another $280 to them (this was going to be the difference of what they will pay for the new ecu to the audi dealer minus what I paid them for the original tune of $599  - they were going to spend $8XX). I said fine because I am totally out of options. They are supposed to send the brand new ecu back to me completely stock for my car, and both P0601 ecu’s).
So you see why I am stuck. I will learn by reading here (probably spend all my free time reading the forums).  I will have another used ecu tomorrow and am debating whether or not (before anyone has done anything to it) to plug it into my car. From what I understand, it should attempt to start the car and then after about a second or so kick out because the immo hasn’t been programmed to my key. Is this a bad idea? Will it mess with the other components in my car or will it screw up the immo components in my cluster or the coil at the key?

I started reading the sections of where to begin, and I know that once I really get started I will look back and wonder why I am asking such basic questions but can you quickly point me in the direction of where to begin. There is so much information here it seems daunting. I know I need the cable to communicate to the ecu, I am pretty sure I will set up a bench test environment once I find out exactly what I need. I believe I have immo 3 with the me7.1.1. IMMO delete would be awsome if it's not really hard to accomplish....

Looking at the positive side of all this, it gives me multiple ecu's to play with. I too would think APR would check for errors as well but what else could it be other than a checksum error with that 0601 code? I read through the checksum error section of this site and the description fits perfectly of how my car behaves. It actually ran to the restaurant and then died... exactly what the checksum section cautions.

Verified it is the ecu...both of them. They did something to make the first two ecu's not work. Before I even posted here, I had a third ecu on the way. I plugged it in last night and it fired right up and then shut off because of immo 3. So...without a doubt, whatever they are doing to the ecu's is making them useless. I scanned the third ecu after I started it and it had many codes (I'm thinking either because the car it was pulled from set the codes, or because it is not setup for my car it threw the codes), but there is NO P0601 code.

Car still doesn't run, but at least now I KNOW what the problem is so a solution can be found....fix the ecu. I wish I was set up or had the knowledge to defeat the immo now so I could get my car running...that would be wonderful. I purchased this car about two months ago and have driven a total of no more than two hours...talk about depressing.

I am still reading like crazy (on this forum) trying to figure out exactly what I need to get started working on the two ecu's I have with the p0601 codes. Hopefully they can be fixed. Anyone want to take a crack at it? I am in the Chicagoland/Milwaukee area.

If you can't find anyone else - mail me one of the dead ECU's over if you like.
Turnaround time will probably be like 3 weeks due to the distance, but I can fix it and put a tune on it for you as well.
I also won't lock or disable anything in the ECU, so you can play with the file if you decide to later.

No excuse given that APR has been doing this for a while now, but AA and S seem to be tricky all the way around.  I haven't had a checksum error (knock on wood), but have had to re-program the EEPROM after every read and and every write.  And merely copying the original, VIN-matched EEPROM to a new ECU to make IMO happy does not work; IMO sets immediately.

Not to hijack the thread, but has anyone definitevely had the MTX plug-in work with ME7.1.1?  I've just loaded my first tune onto an AA box (Stage 1, nothing special, if it seems to work I'll post it) and slowguy has me plenty worried that I'll suffer the same issue.

I'd offer to flash a stock tune back to one of your ECUs, but I've not had any luck with bootmode, and I'm not sure Tony's tool can flash over an APR tune?