Hi, i'm a new member and have an issue with my XC90. Water seems to have leaked into the car on the drivers side damaging the ECU. Is this an expensive fix?

 

is it the ECU or the connectors? what year is the car? Did you try cleaning the connectors with an electronics cleaner etc? What other symptoms/fault codes are suggesting to you the ECU is damaged? Did you check fuses/relays as well?

The problem with replacing the ECU is that for newer years the various computers are "paired" meaning they need to be programmed to talk to each other (and I'm not even sure if a used ECU can be reprogrammed). One alternative is to have your ECU sent out to be rebuilt - Check out shops like Xemodex and Midwest ABS to see what they offer. They also have useful info on their sites.