Hey guys, long time lurker but this is my first post.

I have had speedo issues with my mk6. I have had the VSS replaced and the didn't work, the auto electrician said it was the ECU. Are they just chop and change? I've noticed people selling it with keys / ignition barrels. Has anyone here changed an ECU before? Is there anything to keep an eye out for and could someone please help me find the right one for my car, as it seems to me the serial numbers are unique on them. 

 

 

Thanks :) Curtis

my understanding is that if you replace the ECU, your key will not unset the immobiliser in the ECU that you installed.

What is the issue with the speedo?  is it dead and never moves or works intermittently, or works all of the time but gives an incorrect speed?   can you be 100% sure the speedo itself is not faulty.

are there any other issues with the car like it does not run smoothly or runs erratically?

can we be sure the autoelectrician is correct. I assume that if you spend money on the ecu and the problem persists he will accept no responsibility for his faulty diagnosis.

If someone says 'well I guess it must be the ECU then' this might translate as 'I have no idea and I want to go home now'

16 minutes ago, isetta said:

my understanding is that if you replace the ECU, your key will not unset the immobiliser in the ECU that you installed.

What is the issue with the speedo?  is it dead and never moves or works intermittently, or works all of the time but gives an incorrect speed?   can you be 100% sure the speedo itself is not faulty.

are there any other issues with the car like it does not run smoothly or runs erratically?

can we be sure the autoelectrician is correct. I assume that if you spend money on the ecu and the problem persists he will accept no responsibility for his faulty diagnosis.

If someone says 'well I guess it must be the ECU then' this might translate as 'I have no idea and I want to go home now'

The speedo reads 0 all the time. I have replaced the VSS and checked power is running around the whole system. I think the ECU is the only thing left.

how do you know the speedo itself is not faulty?  I am not saying it is, but replacing an ECU when there is a chance it is the speedo unit itself?

On 11/10/2017 at 6:56 PM, isetta said:

how do you know the speedo itself is not faulty?  I am not saying it is, but replacing an ECU when there is a chance it is the speedo unit itself?

I have already replaced the VSS. If I needed to replace the clocks it requires a full reprogram or a new ECU from the same car as the clocks and locks ect. They're all programmed together

IF you are sure that the ECU is at fault. I would send the ECU for an ECU repair you can google ECU repair  on the internet that way you will get your own  repaired ECU back with all your car settings intact saving you a shed load of problems you will have with a brand new one IE" programming it to your car and keys etc"

19 minutes ago, Gizza11 said:

IF you are sure that the ECU is at fault. I would send the ECU for an ECU repair you can google ECU repair  on the internet that way you will get your own  repaired ECU back with all your car settings intact saving you a shed load of problems you will have with a brand new one IE" programming it to your car and keys etc"

Yeah, it's still an expensive one so I am going to look into some other possibilities before I do that but i will most likely send it to ECU Doctor or something.

Hi have you tried the "secret" menu that tests dash bulbs,gauges which should hopefully test speedo by raising the needle from start 

to full speed and back to start

turn key to first position then press and hold time adjust button below clock mileage readout should show TEST then press button

to scroll through lamp test,speedo and other read outs ( don't know what they are for)

hope this helps