NefMoto

I just picked up a 2000 S4 tiptronic sedan and I just noticed there is a "L" box ECU in it when there should be a "B" box.

The car runs but when I start it up the cluster beeps 3 times and the CEL, ABS & BRAKE dummy lights don't light up even when I do a test thru VagCom. Also I can't connect to the ABS controller, is all this happening because the wrong ECU is in there?

here's some codes I have too:

Address 01: Engine Labels: 078-907-551-AZA.lbl
Control Module Part Number: 4B0 907 551 L
Component and/or Version: 2.7l V6/5VT G 0003
Software Coding: 06652
Work Shop Code: WSC 02325
VCID: 2D4FC485E7C95C70BAA
2 Faults Found:

16502 - Engine Coolant Temp. Sensor (G62)
P0118 - 35-00 - Signal too High
18014 - Rough Road/Engine Torque Signal from ABS
P1606 - 35-00 - Electrical Malfunction

You need an ABS module, sounds like someone removed the LED's in the cluster. As for the L-box causing issues, I'd say yes IF you had any maf related codes, but you do not. Check the MAF, chances are it's been converted to hitachi (or the bin has been altered to run a bosch maf).

Do you know if the ecu has a stock file in it? Is it possible it has been flashed or modified?

Do you have access to a flashing cable?

Do you have access to a spare ecu?

Control Module Part Number: 4B0 907 551 L

I automatically assume (stupid, I know) people understand how the nomenclature is used.

oops. LOL.

Unfortunately the person I picked it up from wasn't an enthusiast and didn't have much info about the mods but did have maintenance records and stuff like that. I'm guessing the L-box is tuned but I'm not positive. It's lowered and has upgraded boost tubes and has a vent boost gauge so it has been modded by someone. I took a quick peek and the MAF housing says Bosch so maybe the ECU has been adapted to run the Bosch MAF but maybe the cluster needs to be adapted too and that's why the CEL, ABS & BRAKE lights aren't working.

I am trying to source a B-box ECU to swap in and see if that fixes anything.

I do have a flashing cable but I still need to piecing together a workstation to be able to start bench flashing.

If it is a 4B0, its the wrong kind of "l-box"


You don't need a bench flashing setup to read/write your ecu. You may need one to unbrick it if you screw it up :)

Damn you're right, I just realized 8D0907551L is what I thought was in there but it's the wrong "L" box, that one is for a A6 now I am really confused as to how this thing is running!!!!

I just need to find a B-box and start over  :(

No you don't. The a6 and s4 ecu's are interchangable. Just verify (by looking at he flash) that the MAF tables match the MAF that is installed in the car.

The A6 L-Box runs the Bosch MAF.  It was used on 2000-2001 A6 2.7T Tiptronics.   Probably someone fried the first ECU then swapped in the 4B0 ecu.   

Look - the softcodes (06652) label it as an A6 Tip with ABS but no ESP as well.  You should at least change the softcodes on it to match your ride.   I think there is a post around here to do that.   Have to login in vcds prior to recoding otherwise the new code won't stick.

Recode and delete the fault codes, then take it from there.

Soft coding is correct other than the platform specific digit, which has no bearing on anything. A 2000 s4 tip should be 06651 as it does not have ESP. Not an issue.

Oh yeah, I assumed he had ESP because I'd only seen this code in cars equipped with it.   Pops up sometimes when the car has spun the tires.  Must have just been a coincidence.

18014 - Rough Road/Engine Torque Signal from ABS
P1606 - 35-00 - Electrical Malfunction

So the OP should just clear codes, then troubleshoot any codes that comes back.   ECU is not the root of any problems.

thanks guys for all the help, I picked up the appropriate B-box ECU and it still throws the same codes as soon as I clear them, turns out the ABS module is no good and one of the CTS wires was broken.

WTF!

A DTC that accurately reports a real problem and that shouldn't be disabled!

Well, that is a surprise :)