Magna ABS alarm - Update

[Ext User(Alan Rutlidge)]

Hi all,

Just a thank you to all those who offered advice with this problem as
below -

Got an interesting fault here.

From a cold start the anti-skid (ABS) light comes on and stays on. Likewise
the traction control (TCL) turns itself off and can't be reactivated. After
the engine has been running for a minute, if I switch off and restart the
anti-skid light goes out as per normal and the traction control can be
switched off and on as per normal.
If the engine has been switched off for say 30 minutes (but not cold), the
same problem occurs.

Car is Magna TJ Sports auto, 60,000km on the clock. During a recent
scheduled service they replaced the brake pads on all four wheels. Any
ideas what might be wrong? And please no idiot replies like " ..you bought
a Magna..."

Outcome-
** Checked the voltage of the battery before starting = 12.6 volts which is
normal for a fully charged battery.

** Checked battery voltage after switch off and after engine had been
running about 10 minutes = 12.74 volts.

** Checked battery fluid level. Not as high as could be but not below top
of the plates either.
** Topped up with distilled water to maximum level and took car for a half
hour drive.
** Next morning, started up engine from a cold start - no more ABS and TCL
alarms. :-)

** Looks as although 12.6 volts is nominally 100% charge the battery
voltage may have been pulled too far down during cranking even though the
starting was effortless. This may have triggered the alarm conditions.

** Just checking a few other items under the hood. Considering the car was
recently serviced the battery level had obviously not been checked and
topped up, neither has the brake fluid, which according the service schedule
should be replaced every 24 months irrespective of km travelled. During
servicing they did neither even though they charged for it on the invoice.
Needless to say the service manager will need to do some fancy talking to
wriggle his way out of this one.

I can understand why a lot of people are moving towards the home / office
visit type service. At least the slightly mechanically / technically
inclined can keep an eye on what the service tech is doing or not doing as
the case may be. Also when they spot something wrong out of the normal
service item they can discuss and point out the problem there and then. Far
better than trusting someone over the phone who usually calls up right in
the middle of a meeting with the "bad news" your brakes need replacing.


Cheers,
Alan

[Ext User(Klompmeester)]

"Alan Rutlidge" <don't_spam_me_rutlidge@iinet.net.au> wrote in message
news:4742dc97$0$4029$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> Hi all,
>
> Just a thank you to all those who offered advice with this problem as
> below -
>
> Got an interesting fault here.
>
> From a cold start the anti-skid (ABS) light comes on and stays on.
> Likewise
> the traction control (TCL) turns itself off and can't be reactivated.
> After
> the engine has been running for a minute, if I switch off and restart the
> anti-skid light goes out as per normal and the traction control can be
> switched off and on as per normal.
> If the engine has been switched off for say 30 minutes (but not cold), the
> same problem occurs.
>
> Car is Magna TJ Sports auto, 60,000km on the clock. During a recent
> scheduled service they replaced the brake pads on all four wheels. Any
> ideas what might be wrong? And please no idiot replies like " ..you
> bought
> a Magna..."
>
> Outcome-
> ** Checked the voltage of the battery before starting = 12.6 volts which
> is normal for a fully charged battery.

Pretty normal.

> ** Checked battery voltage after switch off and after engine had been
> running about 10 minutes = 12.74 volts.
>

That too.

> ** Checked battery fluid level. Not as high as could be but not below top
> of the plates either.

The level should be just covering the top plates.

> ** Topped up with distilled water to maximum level and took car for a half
> hour drive.

Maximum us in as full as it could be? Be careful, batteries that are too
full will seep acid over time under normal charging conditions and can also
shorten the life of the battery and cause a nasty mess under the bonnet.

> ** Next morning, started up engine from a cold start - no more ABS and
> TCL alarms. :-)
>

For the ABS module to play silly buggers the cranking voltage needs to drop
significantly and should be notable by a drop in cranking performance.
You should check the battery voltage with an analog voltmeter as you are
cranking the engine. If it drops below 9V, the battery is struggling.

> ** Looks as although 12.6 volts is nominally 100% charge the battery
> voltage may have been pulled too far down during cranking even though the
> starting was effortless. This may have triggered the alarm conditions.

Unlikely unless the battery has a weak cell which is also unlikely because
it starts fine.

See how it goes, but it doesn't really add up to a battery fault from your
description.

As for the service items not having been done, make some noise about those
for sure.