'98 Vectra ABS tricky prob...

I've bought a 2nd hand Veccy 5 months ago, already fixed something
(under dealer's warranty).
Last week I was travelling from home (Perth) to Glasgow Prestwick
Airport (~150 miles), and halfway (almost) the ABS warning dashboard
light came on. I wasn't bothered too much, as my driving style is not
affected by the lack or the presence of the ABS. After I left my
passengers at the terminal building (a 2' stop) the light was off, and
remained off through the short trip to the airport long term parking.
Eventually we came back from our vacation after a week, and I drove away
from the airport with the ABS light steadily OFF. Again, almost halfway,
the ABS warning light came on. And again, the very short stop to unload
my passengers and the luggage was enough to 'rest' something: when I
moved the car to the street parking, the light was off.
I've used my car since then only for short urban trips, and the light
never came on again.
What's your diagnosis?

 

check for debris around the sensor, might be getting hot or WHY

mike

 

Once upon a time,
mikeFNB came along and stated:

| check for debris around the sensor, might be getting hot or WHY
|
| mike

Hmmm.... something that I was yet thinking about. I'm not the lucky
owner of a Haynes for my car (I've had one for my Chrisler Voyager), is
that someone is sooo kind to help me find the sensor position? It's a
'98 Vectra 1.8 hatchback.

TIA

 

Hi,
The fault you mention is, almost certainly with your tyres!!!

You will most likley have mixed manufacturer tyres on one or more
axles. A common misconception is that all similar sized tyres are made
to the same specification, I.E. dimensions. They are not.
What is happening is, due to a slighty differing rolling road
radius of the tyres, the ABS is sensing a wheel speed difference
between these respective sensors. It thinks you are skidding as in
effect, one wheel is going faster/slower than, the other.
Simply change your tyres around on your vehicle. Try to keep the
same make on each axle.
The same thing can also happen if you have a worn tyre on one
side and, a new tyre on the other.
This fault only shows up at prolonged motorway speeds as, the
speed and length of time involved to log this type of fault within the
ABS Ecu.
Hope this helps.
Bilko130

 

Once upon a time,
Bilko130 came along and stated:

| || Once upon a time,
|| mikeFNB came along and stated:
||
||| check for debris around the sensor, might be getting hot or WHY
|||
||| mike
||
|| Hmmm.... something that I was yet thinking about. I'm not the lucky
|| owner of a Haynes for my car (I've had one for my Chrisler Voyager),
|| is that someone is sooo kind to help me find the sensor position?
|| It's a '98 Vectra 1.8 hatchback.
||
|| TIA
|
| Hi,
| The fault you mention is, almost certainly with your tyres!!!
|
| You will most likley have mixed manufacturer tyres on one or more
| axles. A common misconception is that all similar sized tyres are made
| to the same specification, I.E. dimensions. They are not.
| What is happening is, due to a slighty differing rolling road
| radius of the tyres, the ABS is sensing a wheel speed difference
| between these respective sensors. It thinks you are skidding as in
| effect, one wheel is going faster/slower than, the other.
| Simply change your tyres around on your vehicle. Try to keep the
| same make on each axle.
| The same thing can also happen if you have a worn tyre on one
| side and, a new tyre on the other.
| This fault only shows up at prolonged motorway speeds as, the
| speed and length of time involved to log this type of fault within the
| ABS Ecu.
| Hope this helps.
| Bilko130

Nope, same make/model tyres on front and rear...
Front wheels brand new (less than 1k miles, changed by the dealer at
buying time, guaranteed, they had the stickers still on and the
red/yellow line around) and rear wheels were the old front ones, wear &
tear the same (measured the thread depth by myself with callipers!).
If the ABS ECU is so sensitive to raise a failure with a 3 mm thread
difference between the front and the rear axle, I'm gonna blow the
dashboard light with a huge hammer, it's ridiculous!
Don't tell me that keeping my car steered for 10 miles (this will give a
difference betwen the inner and the outer wheels) the ABS ECU can
trigger a fault... It's so dumb?
I've had another car with ABS (a Chrysler Voyager, a quality car), and
despite having the same configuration (newest tyres front, oldest tyres
rear - the whole set too expensive to replace in one shot, moreover the
front tyres usually lasted 1/2 the rear ones) I've *never* had an ABS
warning signal even with a 700-miles-in-one-shot trip.
I'm not saying that what you are saying is wrong, just that if it's true
it sounds weird (almost) with my types configuration.
Finally, I've done the same trip 4 other times, with the same tyres, and
the ABS light never came on, even for a second.
That's something that has changed during the winter, maybe debris (the
grit salt?) accumulated on the sensor(s)?
Where are they?

Comments welcome.

 

I'd go with full of crap. if you take a wheel off, you should see a gear
like wheel as part of the hub assembly. somewhere, there will be the sensor
almost touching it. (sould be identifiable by wires going to it.) get a
stiff nylon brush (or brass, but not steel) and clean out the cog if it
looks clogged. check connections to sensor, i.e. look for broken wires and
unplug/reconnect any connectors a few times. repeat wit the other wheel on
the axle then test drive. on a hunch, I would do the rear axle first. dont
forget to tighten the wheel nuts.

Mike

 

Once upon a time,
Mike came along and stated:

| I'd go with full of crap. if you take a wheel off, you should see a
| gear like wheel as part of the hub assembly. somewhere, there will be
| the sensor almost touching it. (sould be identifiable by wires going
| to it.) get a stiff nylon brush (or brass, but not steel) and clean
| out the cog if it looks clogged. check connections to sensor, i.e.
| look for broken wires and unplug/reconnect any connectors a few
| times. repeat wit the other wheel on the axle then test drive. on a
| hunch, I would do the rear axle first. dont forget to tighten the
| wheel nuts.
|
| Mike

Thank you for your help, I'll give it a try.

Cheers!