you lot know everything, i've been searching over and over the internet, audi, vw forums, the lot, and i've not really found anything conclusive.

got this on vagcom/vcds

00285 - ABS wheel speed sensor; Front right (G45)
30-00 open or short to plus

now, i've not registered the VCDS yet, will do when i get paid next week, but the next one is

00287 - ABS wheel speed sensor; Rear right (G44) (guessing from the fault codes on ross tech site)
35-00 (not sure what this bit would say. will register next week when i get paid)


i've taken a the front right wheel off, and put a mutimeter in the sensor plug, put the car in gear and let the clutch out, and can see that a reading is being created by the wheel speed sensor, so the fault lies somewhere else.

anyone know? i'm suspecting the abs module, i've seen some connections tend to break in there, but with very little experience in soldering or electronics, i suspect i could make it a lot worse. the info on connections breaking in the abs module tend to have other faults showing too, like missing comms and stuff, but i don't have these

any one sorted anything like this before? the aim is a free fix, as always with this car. so far all the major engine faults have been fixed for about £30. ABS is the only major one left.

[Edited on 15/5/13 by blakep82]

Wiring faults are very common obviously the plug in the wheel arch but also water ingress corrosion the multiway plug at the ABS unit quite often gives problems when this is the fault it is not unknown to have replace the both ABS unit AND part of the loom.

I would start by undoing the multiway connector at the ABS unit and checking the sensor from that there, you should also look for signs of blue-green corrosion and the plug ans socket. If this is the case a clean with "Corrosion Gone" (available off ebay) or similar might work but the pins on the ABS unit are very fragile and difficult to clean.

The plug at the wheel end is up inside the wing behind a rubber grommet, so is nice and clean and dry. The multiplug is also clean and dry with no corrosion.
Although, taking it off gave me an idea. If I knew what pins each sensor were on, I could stick the meter in the plug, spin the wheel again, and check the signal reaches the plug. If it does, the fault must be in the module. The fix or replace
Its a bosch 5.3 I think?

blake to test can you swap the abs sesors over from side to side and see of the fault stays or moves ?

hope that helps ( probably not )

Agriv8

PS let me know how you get on registering VCDS as thats my next 'treat to myself '

have a look here

http://www.bba-reman.com/content.aspx?content=audi_a4_amp_a6_1996_2001_and_vw_passat_1996_2001_abs_pumps_commonly_failing

I have an a6 I have full version vcds and you can check individual wheel speeds as you drive (or preferably someone else driving....) but I'm in Germany so can't help but maybe someone will be able to. When I had issues it was the abs ecu - cost me £80 for a used one. Be aware that dealers will often tell you the abs pump has be replaced with the ecu but they are available separately

[Edited on 15/5/13 by luke2152]

Take care, Reman units often :-) are no better than the originals.
Sadly Bosch bits are Not the world's best quality imo.
Sometimes one can get "slightly' warranteed Parts from a Wreckers for surprisingly few $$
Check there first?

[Edited on 15/5/13 by Bare]

My ranger rover started throwing ABS faults, it was a shot wheel bearing in the end with the sensor at the limit of its working range.

well, here's what i've been up to today:

front wheels off the ground

-as luke suggests, i plugged in VCDS, front and rear left show a speed, front and rear right, show zero.

-used a multimeter set to AC volts on the front right sensor, spun the wheel, shows 0.9 at idle speed, in gear.
with the sensor unplugged, checked continuity between the wheel speed sensor plug and the abs module plug. all ok there

-plugged it all back together and checked wheel speeds on VCDS, nothing for front right, but front left working fine

all seems to suggest the abs module.

HOWEVER

jumped the cables between the front left and front right sensors (ie feeding the left sensor signal into the right front cables) jammed the right wheel so the left spins, plugged in VCDS and it shows 15km/h at both front wheels.

so, seems to suggest the ABS module is working, as it CAN get a signal from both sides
suggests the sensor is at fault; but i can get a reading from the multimeter off the front right sensor on its own

as far as i can tell, no individual part is at fault, but as a system as a whole, it doesn't work. total mystery to me

and i've not even started on the back one yet...

i guess a new sensor is the best place to start?

i changed the cv joint last week, but the fault was there before i changed it too.

If you can get into the ABS module in vagcom, go to Measuring Blocks, either group 1 or 2 will be Wheel Speed.

Just hook it up and go for a drive and see whether the signal is intermittent or never there (for health and safety issues you should do this as a passenger in the vehicle )

1) Wheel sensors are known to fail. £50 from VAG, £10-15 from ebay/GSF. Non-genuine quality varies.
2) Wheel sensors are so seized in on these cars that I'd be amazed if you managed to "swap two over" without actually breaking both of them in the process.
3) Reluctor rings are known to rust and fail - fairly cheap and easy to replace.

I'd tackle the sensor/ring first, before even thinking about ABS ecu's or modulators (always fix by replacement starting from the cheapest component!)


*ETA: not sure why it took so long to post, you've clearly done the wheel speed check, just saw your thread as it came up after I posted..

[Edited on 15/5/13 by PSpirine]

That is not what mine was doing when the ecu was shot so hopefully nothing serious (mine wouldn't connect to the ecu module)
Did you take voltage off the good sensor to compare with the bad one?
Have you actually tested the abs with some heavy braking?
Could it be an intermittent fault with a dodgy wire or plug or is it failing all the time?

quote:

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Originally posted by mark chandler

My ranger rover started throwing ABS faults, it was a shot wheel bearing in the end with the sensor at the limit of its working range.

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quote:

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Originally posted by luke2152
That is not what mine was doing when the ecu was shot so hopefully nothing serious (mine wouldn't connect to the ecu module)
Did you take voltage off the good sensor to compare with the bad one?
Have you actually tested the abs with some heavy braking?
Could it be an intermittent fault with a dodgy wire or plug or is it failing all the time?

---

I've had a similar fault on a later model a3 and it was the sensor. As already said you need to be able to read the wheel speed live. Turned out the faulty one on my car was reading double the speed of all the other sensors, just putting a meter across the sensor doesnt really tell you much. The sensors on Audis are hall effect BTW.

Hth Dan

well, could have sworn it would be a wiring fault, with it being the front and back right hand side at fault, and that the meter was showing it worked, while VCDS showed nothing, new sensor came today, fitted, and it seems to work well now. still need to set it up right, as it reads 14kph (thats what VCDS shows) where the left side shows 15, but i suspect it could do with being pushed in a tiny bit further. don't want to go too far though. no way of knowing til it too late really...
back one's on order now.
Thanks for all the suggestions and help