I have a 2001 Elantra and get the P0605 code indicating the ECU needs to be replaced. An ECU cost $700 at the Hyundai dealer, $440 at Autozone, and $120 from a junk yard. I took mine out, it reads Hyundai part number 39105-23020 / 39109-23020 and Siemens part# 5WY1402C Index 03.....another code on the label reads SIMK41

I can find similar ECU's at the boneyard, every number is the same, except the Siemens part# It is 5WY1402A index 01, but the Hyundai part# is the same. The box looks the same. B4 I spend the money, I want to find out if the Siemens code matters...what does the A and C stand for, and what is the index #? Does anybody know? At the local Hyundai dealer nobody knew, but then of course they want me to buy their $700 part

Thanks

 

Junk yards are great for mechanical parts but not for electronics. Personally, I wouldn't trust it.