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vcds coding to reset and prime haldex


Staff Team
United States
What I Drive
2015 s3
at times you might notice you have no traction in the rear or if you did a service.
i recommend that you do this to reset the pump. most of the time people think the pump is broken and not working. this usually will solve the issue.

with vcds:
get the engein & haldex warmed up to temp
leave engine on while doing the coding reset
22 awd
04 basic settings
drop down - pump motor

you'll listen for the rear haldex pump prime. it will take a few. so let it finish on its own. do not interrupt it, do not turn off engine, do not touch the vcds software.
it will signal you when its done.

when its done, close off the vcds system and disconnect the cable
cycle the engine by turning off the engine for 1 minute.
turn it back and take it for a drive.

remember, the system is like a PC. you should do this reset once in a while. i feel mine needs this reboot every 6 months to 1 year.
the cause:
it usually depends on how healthy your car battery is. if you have a stock OEM battery i would recommend swapping it out asap. oem vw battery are horrible and causes electrical gremlins even if the battery looks like they are working fine.
so a crappy car battery is usually the cause, from my experience.
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