Biturbo5V

I plan on buying a spare ECU and putting a chip in it. I've read this is the safest way since you can swap in the OEM ECU when bringing it in for service. Is it worth the extra money or will the dealer be able to detect that the ECU has been swapped and be suspicious?

Thanks,

Biturbo5V

BUFFALONOGAROpebFATS

even then they can tell how much time the car has been driven after the ecu has lost power (been dissconnected). but this is stillthe safest way, as you could always say that you tried to troubleshoot your own problem and dissconnected the battery or something, get creative.

imo get another ecu, it is the safest route

Avantgarde

When you swap the ECU it will trigger a power disconnected code. Although this would not prove that you swapped ECU's (because it is the same code that you would get if you disconnected the battery), it is a huge indication that you have been messing with the ECU.

The second obvious indication is gummed up screws and a scratched up ECU from popping the clip. If you are careful with these two things and clear the codes many would tell you that the dealer will not know.

Some conspiracy theorists will tell you there are other ways and the dealer is all knowing - personally I think this is BS.

The bottom line IMO - swapping the chip will be fine for run of the mill warranty stuff - but when it comes to blown turbos - shot transmission etc. they may look a little harder.

Good luck reading the archives.

Biturbo5V

I do have an aftermarket battery (optima) and do alot of work on the stereo from time to time. Is disconnecting the battery the same as disconnecting the ECU? Not knowing alot about ECU and engine stuff (besides the basics) I don't want to tell them I did something if it is not correct.

Thanks for the assistance,

Biturbo5V

Rory

It's generally helpful to have a spare ECU. e.g. software upgrades, faults with the chipped one

ModifiedA4

you need to clear the "power loss" DTC in the engine computer after you switch.

unfortunately doing this resets all the emissions adaptions. driving for a few days will restore these, so just make sure you swap ecus a few days ahead of time to be perfectly safe.

<b>now this is important:</b>

your second ecu (the one that didnt come with the car) will have a different <i>workshop code</i>, this is a dead giveaway. use vag-com to read the WSC from the original ecu and program the second ecu with this code. this only has to be done once.

if you do all three things listed above (clear code, wait for emissions to adapt, change the WSC) the dealer has no way of knowing (via the computer interface) that an ECU has been swapped (if both ecus have the same part number)

BUFFALONOGAROpebFATS

if you do alot of stereo work then thats a perfect excuse. the ecu will read a code (unless you clear it with vag) power supply voltage too low, or something along those lines, which menas the ecu lost power, whether it was disconnected from port, or the battery is disconnected. thats your best scenario. everything else is much riskier.

joe

Avantgarde

it is the same DTC.

Leif S4

Drive a 100 miles or so after clearing codes to reset the readiness codes for the exhaust and evap systems... it's another tell tell sign you've swapped ECU's

JasonS4+Festicle

clear the codes BUT the readiness codes will all be failing until you drive some distance.

ot that I advocate fooling the dealer, but if you wanted to, the best way would be to change ECUs, clear codes. Drive 50 or so miles and then check readiness codes, if you're passing everything, then you're ready to go to the stealership.