help i got no 4 wheel drive,had it scanned no faults reported and haldex communicating with ecu and abs anyone know what to check next
thanks
thanks
HALDEX NOT WORKING
- Thread starter bogard
- Start date
Thanks for the idea, the earth strap is connected also on measuring blocks the brake light and handbrake switch work.
It was the pre charge pump that failed on mine and it prevented the haldex unit from operating completly. It's the small pump with a black plastic tube and plug in connections. It won't show any fault codes if it has packed up. It's in the region of 250 quid new and nobody seems to want to split one from the rear diffs that are for sale on eBay. It would be worth contacting a vag tuner in Bridgwater called tsr performance (details on google) they do a lot of 1.8t conversions and the guy informed me whilst i was having other work done there that they have got complete rear diffs just lying around. So maybe worth a try. Good luck.
Thanks very much for replying,does anybody know how to test if the pre charge pump is working or not?
I don't know how to test it I'm afraid. If you do a search there was a thread on here not so long ago on a similar subject. However I think most of the sugestions have been covered in this thread. Worth checking the fuse for the haldex if you haven't already. If you do end up changing the pump you will need some replacement haldex oil.
you can test the pump is working with vagcom under simulation tests? cant remember,i was playing around in vagcom and found this,heard mine come in and out etc.
like this...drivetrain, 22 AWD ,then 03 output tests
http://www.ross-tech.com/vcds/tour/open_screen.html
http://www.ross-tech.com/vcds/tour/open_screen.html
i tried the output tests but nothing seemed to happen but a little click.
if a rear wheel is jacked up then the output clutch is engaged should the wheel be locked or spin ?
if a rear wheel is jacked up then the output clutch is engaged should the wheel be locked or spin ?
dont know what will happen if jacked up,i suspect even with the pump working and the coupling engaged it will still act like a normal open diff and with one wheel in the air still turn regardless,mine i could hear the pump working when sat in the car,if yours is not making any noise when activated in output tests its probably dead or a bad connection.
Agreed, the fuse for the Haldex would be my first port of call, followed by the plug for it - I believe it's on the engine bay somewhere.
hi i had the same problem with the haldex pre charge pump and in vw or audi these little pumps cost 400 quid i i was looking to get that pump for a month and i found company or something like that i sended them my old pump and they replaced new engine and other parts needed for that pump it costed me only 150 quid and i got new pre charge pump new engine new seals and now almost three years and no rpoblems at all
most of the time is the pump, cost nearly £120 second hand, I changed 2 controllers before this with no joy, I could hear it working even if the car is not moving. the wheels should spin if the car is jacked.
