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Author Topic: ECU with immobiliser 3  (Read 13129 times)
smeege
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« on: February 25, 2011, 11:07:30 PM »

I came across Nefmoto by accident while looking for a fix for a customers car. I've been reading everything here for 2 nights straight. It's great, so much info. I'm the only mechanic at a car lot that specializes in Audis. 15 out of the 20 cars currently there are Audis, 3 of which are b5 s4s. This is the holy grail of web sites to me! My personal car is a a6 2.7t 6spd, and i can't wait to start tuning it, but back to how i found you guys in the first place.

I'm working on a customers '01 A6 2.7t with immo 3. Somebody left the key on (not me), and fried the ECU. I can still communicate with it using VCDS, is there a way to turn the immobiliser off, or can I clone the ecu? I have a used ECU for it, but no key code. I just get the flashing immo light. The old ecu runs all the actuators, but won't adapt the throttle body, which i've found typical for jump-start ecu failures.

I've done a little hex editing, and I think I can figure it out, but I'm in a time crunch, so I could use some help.

Thanks in advance, I'll be back here often as I try to tune my A6. Any tips on tuning stock setup?
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zillarob
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« Reply #1 on: February 27, 2011, 08:21:13 AM »

vagtacho cable to learn new keys?

On coding out the immo search threads by user k0mpressed, here and audizine.
I think he has pretty good luck with that stuff.
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smeege
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« Reply #2 on: February 27, 2011, 04:54:07 PM »

Thanks, Zillarob. I found another post here about cloning ECUs, but I haven't successfully retrieved a bin file from the old ECU, it always stops at around 20%. Same problem when I tried to read my car.

If I can get a bin file out of the old ecu, can I locate the PIN code in it, and just use the PIN to match replacement ECU to the cluster? Does anybody have the address for the pin?
« Last Edit: February 27, 2011, 04:58:44 PM by smeege » Logged
zillarob
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« Reply #3 on: February 27, 2011, 10:33:14 PM »

On the s4 i know the tacho 2.5 will give you the pin for the d11 clusters but havent had any luck with the d12. 3.01 on the way, will see what kind of damage i can do with that.

kinda doubt the pin is in the bin, but not sure.
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carlossus
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Leon Curpa Stg1+


« Reply #4 on: February 28, 2011, 07:11:31 AM »

The PIN is in the serial EEPROM rather than the FLASH but I don't think it will help you much.

The quickest solution is to get another ECU with the exact same H/W and S/W version and desolder the EEPROM (95040) from the bad one and fit it to the new one. Then it'll just work.

If that's a no go you can disable the immo by reading, editing and reprogramming the serial EEPROM. I don't know the exact address for your ECU, but it's a couple of bytes + adjust checksum.

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smeege
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« Reply #5 on: February 28, 2011, 01:49:59 PM »

Thanks again for all the help. I think desoldering eeprom is best bet. I've been practicing on junk circuit boards all morning, but I haven't found a good pic yet that shows exactly which chip is the eeprom, I see a small (1/4") 8 pin chip with 950403 on it. I a little nervous, since my boss just paid $200 for the used ECU, and it was the only 4B0907551T we could find.

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smeege
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« Reply #6 on: February 28, 2011, 02:59:53 PM »

OK, I've figured out that 950403 is the serial eeprom. How hot can these chips get while I'm soldering them before they're garbage?
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carlossus
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« Reply #7 on: February 28, 2011, 03:49:20 PM »

Remove the 95040 from the new ECU first as that one is full of junk anyway.

They can get very hot, but keep it brief if you can.

My tips: -
Mask the exposed board with tape, an unseen solder splash could ruin your day.
The chip is glued to the board so it'll need prising off - use something soft like a toothpick or plastic point. It will come off much more easily once the chip is hot.
If you just have a soldering iron (no wick or sucker) then apply lots of solder so that you are bridging all 4 pins on 1 side with a blob of solder. Repeat on the other side. Put your prising tool under the edge of the body of the chip and apply some pressure with one hand. With the iron now alternate between the two rows of pins until all are molten at once and increase the pressure until the chip lifts.

Then clean up the pins and pads.

I expect there are lots of generic chip removal vids on youtube.

Make sure you double check the orientation before refitting the original EEPROM.

-C
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smeege
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« Reply #8 on: February 28, 2011, 09:23:45 PM »

Carlossus, thank you for all the tips and advice. Since we can't find any other ECUs with matching #s (4B0907551T), I think my boss is giving up and trailering the car to the "stealership" tomorrow.

One last thought, is it possible to find an ecu without immobilizer on it, and flash the T file over? (I didn't catch that there is a separate data dump for immo at first) Maybe even just substitute a different ECU? (Assuming I can find an interchange.)

Tomorrow I'm ordering the cable so I can read the 95040 chips right on the board. It sounds like the easiest solution for my situation.
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smeege
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« Reply #9 on: March 01, 2011, 09:38:36 PM »

Just a quick update, I got the 950403 chip resoldered on new ECU (finally found a little local help soldering). I plugged it in, turned the ignition on, immo light went out, and the car would just crank. Long story short, the ECU now will do the TBA adaptation, and functions perfectly. The fuel filter was clogged, and the girl was driving on the battery for a while, I'm guessing the lowered voltage and flow restriction burnt the pump up. Thank god it didn't end up going to the dealership.

Thanks again for all the help.
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carlossus
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« Reply #10 on: March 02, 2011, 12:11:28 AM »

Great! Thanks for coming back to close off the thread with a happy ending Cheesy
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Tony@NefMoto
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2001.5 Audi S4 Stage 3


« Reply #11 on: March 02, 2011, 04:57:04 PM »

Hurray! Thanks for validating the site as a useful resource.
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