ABS lights up after a while

Hi
I have a 1997 accord wagon (Aerodeck in the UK).

When I start it - everything is fine - the ABS lights up then goes out again.
After a few yards of driving the car the ABS light comes on - why?

If the check is completing fine does that mean that the main components are OK?

Could it be a wheel sensor? - a blown fuse ?


Thanks

 

Assuming this is the same ABS unit that Honda used on the US models (can't
really tell from your posting if you are in the UK, or just hoping for help
from the UK), the ABS is not able to maintain pressure. The unit tries to
pump up for a couple of minutes, then gives up and sets the light. There is
a way to extract the error code from it if you want to know the specific
failure mode. It can tell you if its a wheel sensor, or whatever, but the
symptom you describe normally means it cannot maintain pressure.

Is the ABS reservoir full? If not, look around the base of the ABS unit
under the reservoir and see if there is any leaking brake fluid. If there
is, you might get lucky. There were some systems that leaked around the
external seals and can be repaired. Otherwise, the repair generally
requires replacing the ABS unit for a pretty hefty price tag (somewhere in
the neighborhood of $1000 US).

Fortunately, ABS system failure does not diminish the main brakes, so the
simplest/ cheapest solution is to forget you bought the ABS option and
proceed without. (It was an option after all, at least in the US).

 

My concern is this - this all started the day I went through a new
carwash. Could something have been disturbed? - Also - when the light
first came on I noticed that the tail light had gone. I opened it up
to change the bulb and it seemed to come back on again. Anyhow - I
replaced all the bulbs - tail lights and brake bulbs in the rear
cluster thinking that it may have been an electrical fault - I have
noticed in the past that when my brake lamp blows my BRAKE LAMP and
ABS light comes on.

That didn't resolve the problem. The next day the ABS lamp came on
after 20 mins of driving but now its on as soon as the car picks up
speed - say 5mph.

Would the initial check that is done when u start the ignition
complete OK if there was a fault with the main unit?

Is it safe to unplug the blue connector under the glove box to short
it and check the code? I noticed there was a red one there as well

 

The ABS light comes on with the Brake warning light if it detects the brake
light has been on for 30 seconds. Possible causes (from the '96 service
manual):

- driving with the parking brake on
- open circuit between the backup lights/meter lights (10A) fuse and the
brake system light
- Low fluid in the main (master cylinder) reservoir
- Blown brake system light bulb (you've seen this one).
- Parking brake switch stuck on.
- short to body ground between the brake system light and the parking brake
switch
- Brake fluid level switch stuck "on".
- short to body ground between the brake system light and the brake fluid
level switch
- faulty ABS control unit

Your description with the carwash starting it off sounds like it might be
one of the shorts. Look for a wire with bad insulation (cracked, rubbed off,
exposed wire, etc., in the circuits they mention.

If the problem is maintaining pressure, yes it will. It makes several
attempts over several minutes to pump up and does not turn on the light
until after that.

The connector you are looking for has only two wires and is not connected to
anything. The procedure to check the ABS codes is as follows:

-Short the pins in the connector. A big paper clip works well.

- Turn the ignition to position II "on" but do not start the engine (if you
start the engine with the connector shorted, you will set the engine
malfunction light).

- The ABS light will glow for 2 seconds, then go off for 2 seconds, then it
will flash out the code.

There will be a series of flashes, followed by a 1 second pause, then a
second series of flashes. If, for example, you got four flashes, pause,
then 2 flashes, you would have trouble code 4-2.

- there will be a 5 second pause, then it repeats the code. It will put out
the code a total of three times, then stop.

If you miss count, turn the ignition off, then back to position II and it
will repeat the sequence.

To reset the codes in the ABS, you remove the ABS B2 (15A) fuse in the under
hood ABS fuse/relay box for at least 3 seconds.

Let me know what you get & I'll look it up for you.

 

I had a very similar problem happen with my 96 Integra this past
April. One day, the light just came on shortly after starting to move
and stayed on. Each time I started the car the system would
pressurize fine (could hear the pump) and the light would go off. As
soon as I started rolling the light would come on again.

Observing the car over the next two weeks, the light came on every
time - except one day in the middle where the system worked flawlessly
- which I still cannot explain. Cleaned the four wheel sensors as
best I could with soapy water and a toothbrush but to no avail.

I eventually brought it to the dealer. It turned out that the
left-rear wheel sensor was defective. If I recall, the part cost
about $170CND (~$120US?), plus labor (not sure exactly how much as I
had other stuff done at the same time). Not too bad considering the
alternatives, like replacing the whole computer for $1K+.

Of course, ABS is not a critical system, so if it is not important to
you then you always have the option of just leaving it, as your brakes
will automatically fall back to "normal" brakes.

My ABS has worked fine since... 5 months / 13,000 KM (~8000 miles)


- Kevin

 

there are two connectors under the glove box - a blue one and an
orange one. the orange one has a label saying "ABS ONLY PULSE". I
assume this is the service connector. It has 6 wires not 2 wires as
most people have described. Any ideas which ones I short? The blue one
has several wires as well - but has no label - I assume they used an
orange connector for the ones destined for UK market. By the way - the
car was manufactured by Honda America. All wagons/aerodecks in the UK
came in from the U.S. after '94.

Thanks

 

-------------------------
Imran,

Just for safety's sake, I never put a dead short on a connector, even if
some manual tells me it's OK. I use a 1,000 ohm resistor instead. It
still works like a short, but less likely to cause a catastrophy if I
make a booboo.

I think of it as 'circumventing Murphy's Law'.

'Curly'

-------------------------