ABS light is on

On Tue, 04 Jan 2011 19:05:44 -0000, Chris Whelan
> wrote:

> On Tue, 04 Jan 2011 19:03:34 +0000, Duncan Wood wrote:
>
>> On Tue, 04 Jan 2011 18:57:37 -0000, Chris Whelan
>> > wrote:
>>
>>> On Tue, 04 Jan 2011 10:51:17 -0800, Jeff Strickland wrote:
>>>
>>> [...]
>>>
>>>> The only safe assumption is that if the light is on the system has
>>>> disabled itself. If the system turns out to work when you need it,
>>>> count that as Living Well and thank your lucky star.
>>>
>>> Yep.
>>>
>>> But the light being on doesn't mean the ABS *will not* work.
>>>
>>> Only that it might not, so shouldn't be relied on.
>>>
>>> Chris
>>>
>>>
>> Except that the probability of might is almost certainly well in excess
>> of 99%.
>
> So the statement should be "The ABS light being on means the ABS will
> *probably* not work.
>
> I was just trying to point out that a single indicator light can't be
> relied upon to show the status of a complex system.
>
> Chris
>

It does do a rather accurate job of it though. And the edge case is
somewhat pointless to consider.

"Chris Whelan" > wrote in message
...
> On Tue, 04 Jan 2011 19:03:34 +0000, Duncan Wood wrote:
>
>> On Tue, 04 Jan 2011 18:57:37 -0000, Chris Whelan
>> > wrote:
>>
>>> On Tue, 04 Jan 2011 10:51:17 -0800, Jeff Strickland wrote:
>>>
>>> [...]
>>>
>>>> The only safe assumption is that if the light is on the system has
>>>> disabled itself. If the system turns out to work when you need it,
>>>> count that as Living Well and thank your lucky star.
>>>
>>> Yep.
>>>
>>> But the light being on doesn't mean the ABS *will not* work.
>>>
>>> Only that it might not, so shouldn't be relied on.
>>>
>>> Chris
>>>
>>>
>> Except that the probability of might is almost certainly well in excess
>> of 99%.
>
> So the statement should be "The ABS light being on means the ABS will
> *probably* not work.
>
> I was just trying to point out that a single indicator light can't be
> relied upon to show the status of a complex system.
>


The truth is that your single data point is not an indicator that the
complex system might work.

FOR THE RECORD
I have an E36 with the ABS light on, and it's been on for well over 5 years
that I know of. My car has a problem with the valve body and I don't care
about it enough to fork over $1000. I've driven most of my life in cars that
don't have ABS at all, so having a car with ABS that doesn't work is no big
deal in the grand scheme of things.

"Chris Whelan" > wrote in message
...
> On Tue, 04 Jan 2011 19:03:34 +0000, Duncan Wood wrote:
>
>> On Tue, 04 Jan 2011 18:57:37 -0000, Chris Whelan
>> > wrote:
>>
>>> On Tue, 04 Jan 2011 10:51:17 -0800, Jeff Strickland wrote:
>>>
>>> [...]
>>>
>>>> The only safe assumption is that if the light is on the system has
>>>> disabled itself. If the system turns out to work when you need it,
>>>> count that as Living Well and thank your lucky star.
>>>
>>> Yep.
>>>
>>> But the light being on doesn't mean the ABS *will not* work.
>>>
>>> Only that it might not, so shouldn't be relied on.
>>>
>>> Chris
>>>
>>>
>> Except that the probability of might is almost certainly well in excess
>> of 99%.
>
> So the statement should be "The ABS light being on means the ABS will
> *probably* not work.
>
> I was just trying to point out that a single indicator light can't be
> relied upon to show the status of a complex system.
>


The truth is that your single data point is not an indicator that the
complex system might work.

FOR THE RECORD
I have an E36 with the ABS light on, and it's been on for well over 5 years
that I know of. My car has a problem with the valve body and I don't care
about it enough to fork over $1000. I've driven most of my life in cars that
don't have ABS at all, so having a car with ABS that doesn't work is no big
deal in the grand scheme of things.

On Tue, 04 Jan 2011 19:06:16 -0000, Jeff Strickland >
wrote:

>
> "Terry Pinnell" > wrote in message
> ...
>> I have a 1996 N-reg BMW 328SE Auto. Its ABS light is coming on and
>> staying
>> on while driving. However, using the CHECK button on the computer panel
>> displays 'Check Controls OK'.
>>
>> I haven't been able so far to test it out on a suitable surface, but
>> should I assume it's broken? If so, is a repair likely to be within the
>> capabilities my local garage (which regularly services the car), or am I
>> going to have to take it to an expensive BMW dealer please?
>>
>
> Without regard to what Chris is saying, if the ABS light is on, then you
> should consider the ABS feature to be inactive and your car may skid in a
> situation that would otherwise trigger an ABS event.
>
> The only way to isolate the cause is through the diagnostic port. You
> could
> buy some speed sensors and swap them around until you find a combination
> of
> new andn old that work, but this is a more costly and time-consuming
> approach than paying somebody to plug into the diagnostic port.
>
> The diagnostic port will identify the controller module as the fault, if
> it
> is the source of the problem.
>
>
>
>
>
>

Actually you can diagnose them with an oscilloscope or most decent digital
multimeters. There's enough voltage output to drive the frequency meter on
anything 1/2 decent.
http://www.picoauto.com/waveforms/popular/wave86.html

On Tue, 04 Jan 2011 19:06:16 -0000, Jeff Strickland >
wrote:

>
> "Terry Pinnell" > wrote in message
> ...
>> I have a 1996 N-reg BMW 328SE Auto. Its ABS light is coming on and
>> staying
>> on while driving. However, using the CHECK button on the computer panel
>> displays 'Check Controls OK'.
>>
>> I haven't been able so far to test it out on a suitable surface, but
>> should I assume it's broken? If so, is a repair likely to be within the
>> capabilities my local garage (which regularly services the car), or am I
>> going to have to take it to an expensive BMW dealer please?
>>
>
> Without regard to what Chris is saying, if the ABS light is on, then you
> should consider the ABS feature to be inactive and your car may skid in a
> situation that would otherwise trigger an ABS event.
>
> The only way to isolate the cause is through the diagnostic port. You
> could
> buy some speed sensors and swap them around until you find a combination
> of
> new andn old that work, but this is a more costly and time-consuming
> approach than paying somebody to plug into the diagnostic port.
>
> The diagnostic port will identify the controller module as the fault, if
> it
> is the source of the problem.
>
>
>
>
>
>

Actually you can diagnose them with an oscilloscope or most decent digital
multimeters. There's enough voltage output to drive the frequency meter on
anything 1/2 decent.
http://www.picoauto.com/waveforms/popular/wave86.html

On Tue, 04 Jan 2011 11:06:16 -0800, Jeff Strickland wrote:

> "Terry Pinnell" > wrote in message
> ...
>>I have a 1996 N-reg BMW 328SE Auto. Its ABS light is coming on and
>>staying
>> on while driving. However, using the CHECK button on the computer panel
>> displays 'Check Controls OK'.
>>
>> I haven't been able so far to test it out on a suitable surface, but
>> should I assume it's broken? If so, is a repair likely to be within the
>> capabilities my local garage (which regularly services the car), or am
>> I going to have to take it to an expensive BMW dealer please?
>>
>>
> Without regard to what Chris is saying, if the ABS light is on, then you
> should consider the ABS feature to be inactive and your car may skid in
> a situation that would otherwise trigger an ABS event.

Agree.

> The only way to isolate the cause is through the diagnostic port. You
> could buy some speed sensors and swap them around until you find a
> combination of new andn old that work, but this is a more costly and
> time-consuming approach than paying somebody to plug into the diagnostic
> port.

Disagree.

(The OP's car is pre-E-OBD, so may have limited diagnostics.)

Examining the sensor rings and sensors for physical damage, cleaning
them, then unplugging the sensor connector, cleaning it, and reconnecting
it will resolve 50% plus of ABS faults. The diagnostic cost as a DIYer
will be zero.

The more competent DIYer should then be able to use a multi-meter to
determine which sensor might be faulty simply by comparison of readings.

Compare that to what a BMW dealer (at least here in the UK) will charge
for diagnostics...

> The diagnostic port will identify the controller module as the fault, if
> it is the source of the problem.

No it won't.

In the case I mentioned in another post, the ABS module had a short
circuit internally for the warning lamp output. This wasn't monitored by
the diagnostics. (This wasn't a BMW, I should point out.)

Chris

--
Remove prejudice to reply.

On Tue, 04 Jan 2011 11:06:16 -0800, Jeff Strickland wrote:

> "Terry Pinnell" > wrote in message
> ...
>>I have a 1996 N-reg BMW 328SE Auto. Its ABS light is coming on and
>>staying
>> on while driving. However, using the CHECK button on the computer panel
>> displays 'Check Controls OK'.
>>
>> I haven't been able so far to test it out on a suitable surface, but
>> should I assume it's broken? If so, is a repair likely to be within the
>> capabilities my local garage (which regularly services the car), or am
>> I going to have to take it to an expensive BMW dealer please?
>>
>>
> Without regard to what Chris is saying, if the ABS light is on, then you
> should consider the ABS feature to be inactive and your car may skid in
> a situation that would otherwise trigger an ABS event.

Agree.

> The only way to isolate the cause is through the diagnostic port. You
> could buy some speed sensors and swap them around until you find a
> combination of new andn old that work, but this is a more costly and
> time-consuming approach than paying somebody to plug into the diagnostic
> port.

Disagree.

(The OP's car is pre-E-OBD, so may have limited diagnostics.)

Examining the sensor rings and sensors for physical damage, cleaning
them, then unplugging the sensor connector, cleaning it, and reconnecting
it will resolve 50% plus of ABS faults. The diagnostic cost as a DIYer
will be zero.

The more competent DIYer should then be able to use a multi-meter to
determine which sensor might be faulty simply by comparison of readings.

Compare that to what a BMW dealer (at least here in the UK) will charge
for diagnostics...

> The diagnostic port will identify the controller module as the fault, if
> it is the source of the problem.

No it won't.

In the case I mentioned in another post, the ABS module had a short
circuit internally for the warning lamp output. This wasn't monitored by
the diagnostics. (This wasn't a BMW, I should point out.)

Chris

--
Remove prejudice to reply.

On Tue, 04 Jan 2011 11:10:13 -0800, Jeff Strickland wrote:

[...]

> FOR THE RECORD
> I have an E36 with the ABS light on, and it's been on for well over 5
> years that I know of. My car has a problem with the valve body and I
> don't care about it enough to fork over $1000. I've driven most of my
> life in cars that don't have ABS at all, so having a car with ABS that
> doesn't work is no big deal in the grand scheme of things.

Ah, I see.

You don't live in a country civilised enough to require your car to have
regular examinations to make certain it meets the safety standards the
manufacturer built it with.

;-)

Chris

--
Remove prejudice to reply.

On Tue, 04 Jan 2011 11:10:13 -0800, Jeff Strickland wrote:

[...]

> FOR THE RECORD
> I have an E36 with the ABS light on, and it's been on for well over 5
> years that I know of. My car has a problem with the valve body and I
> don't care about it enough to fork over $1000. I've driven most of my
> life in cars that don't have ABS at all, so having a car with ABS that
> doesn't work is no big deal in the grand scheme of things.

Ah, I see.

You don't live in a country civilised enough to require your car to have
regular examinations to make certain it meets the safety standards the
manufacturer built it with.

;-)

Chris

--
Remove prejudice to reply.

Chris Whelan wrote:
> On Tue, 04 Jan 2011 11:06:16 -0800, Jeff Strickland wrote:
>
>> "Terry Pinnell" > wrote in message
>> ...
>>> I have a 1996 N-reg BMW 328SE Auto. Its ABS light is coming on and
>>> staying
>>> on while driving. However, using the CHECK button on the computer
>>> panel displays 'Check Controls OK'.
>>>
>>> I haven't been able so far to test it out on a suitable surface, but
>>> should I assume it's broken? If so, is a repair likely to be within
>>> the capabilities my local garage (which regularly services the
>>> car), or am I going to have to take it to an expensive BMW dealer
>>> please?
>>>
>>>
>> Without regard to what Chris is saying, if the ABS light is on, then
>> you should consider the ABS feature to be inactive and your car may
>> skid in a situation that would otherwise trigger an ABS event.
>
> Agree.
>
>> The only way to isolate the cause is through the diagnostic port. You
>> could buy some speed sensors and swap them around until you find a
>> combination of new andn old that work, but this is a more costly and
>> time-consuming approach than paying somebody to plug into the
>> diagnostic port.
>
> Disagree.
>
> (The OP's car is pre-E-OBD, so may have limited diagnostics.)
>
> Examining the sensor rings and sensors for physical damage, cleaning
> them, then unplugging the sensor connector, cleaning it, and
> reconnecting it will resolve 50% plus of ABS faults. The diagnostic
> cost as a DIYer will be zero.
>
> The more competent DIYer should then be able to use a multi-meter to
> determine which sensor might be faulty simply by comparison of
> readings.
>
> Compare that to what a BMW dealer (at least here in the UK) will
> charge for diagnostics...
>
>> The diagnostic port will identify the controller module as the
>> fault, if it is the source of the problem.
>
> No it won't.
>
> In the case I mentioned in another post, the ABS module had a short
> circuit internally for the warning lamp output. This wasn't monitored
> by the diagnostics. (This wasn't a BMW, I should point out.)
>
> Chris

0.3v ac when spun at 60 rpm on the fronts and 0.4 on the rears