DIY repairs of ABS hydraulic unit coils (TEVES 04)

I have a (B4) 1995 Passat GLX VR6 with the TEVES 04 ABS system. The
hydraulic unit has one coil for the RF inlet valve that tests
sporadically bad (open circuit or high resistance)

Does anyone know if the electrical side of this part can be taken apart
and re-assembled without damage? Does anyone know of any repair that
is possible on the coils in this unit?

Background:
My car has 160k miles and is 10.5 yrs old so one consideration I have
is to unhook the ABS and go without it. If it is possible, I would
prefer to repair the offending coil obviously due to the high cost of
the part.

I diagnosed the problem with VAG-COM and it showed error code 00259
which is a too-high resistance on the valve N99. What is interesting
to me is that the ABS light often has come on when the engine is
started cold, but if the engine is started hot the ABS light virtually
always goes off (at least during the summer it has). The failure
obviously is at least partially temperature-dependant. This behaviour
had me believing that the failure was due to a sticking spool valve
that somehow was more 'loose' when the unit was hot. However, I have
checked the resistance of the coil at the 15-pin connector to the Hyd.
unit and this one coil indeed reads higher than the others. 9ohm to
open circuit as compared to 7.5 ohm on the good inlet valves.

Thanks in advance for any help! regards, Mark

Mark wrote:
> I have a (B4) 1995 Passat GLX VR6 with the TEVES 04 ABS system. The
> hydraulic unit has one coil for the RF inlet valve that tests
> sporadically bad (open circuit or high resistance)
>
> Does anyone know if the electrical side of this part can be taken apart
> and re-assembled without damage? Does anyone know of any repair that
> is possible on the coils in this unit?
>
> Background:
> My car has 160k miles and is 10.5 yrs old so one consideration I have
> is to unhook the ABS and go without it. If it is possible, I would
> prefer to repair the offending coil obviously due to the high cost of
> the part.
>
> I diagnosed the problem with VAG-COM and it showed error code 00259
> which is a too-high resistance on the valve N99. What is interesting
> to me is that the ABS light often has come on when the engine is
> started cold, but if the engine is started hot the ABS light virtually
> always goes off (at least during the summer it has). The failure
> obviously is at least partially temperature-dependant. This behaviour
> had me believing that the failure was due to a sticking spool valve
> that somehow was more 'loose' when the unit was hot. However, I have
> checked the resistance of the coil at the 15-pin connector to the Hyd.
> unit and this one coil indeed reads higher than the others. 9ohm to
> open circuit as compared to 7.5 ohm on the good inlet valves.
>
> Thanks in advance for any help! regards, Mark

can't you find that part in a junkyard, or is the coil built into the
HCU in some kind of non-removable manner?

just curious,

nate

(who would probably be a lot more help were this a Kelsey-Hayes unit...)

I would guess I could find the unit in a junkyard but I have several
reasons to hesitate to do this.

- I do not want to take apart the hydraulic circuit if I do not have
to. The brakes work fine and there is always the chance that taking
something apart I could contaminate something or twist off a connection
or....

- Junkyards are often not pleasant to work with and who knows what
quality part I could find. I once used an online service where I
posted the part I wanted and got bids for the part. I would probably
do this again if it came down to getting a junkyard unit.

- I prefer to fix the car for free if I can !

Basically, my question is close to the same as you asked.. can the coil
be replace or repaired without replacing the entire unit?

Thanks for your reply, nate!