Re: low voltage and ABS

[Mick <bmwmick@xxxxxxxxxxx>]

At 11:56 AM 8/13/2007, Mark Rivera wrote:
> I was wondering about the low voltage & ABS issue..
>
> Isn't there somewhere we can place a capacitor to provide a buffer 
> for the ABS needs at start time?
>
> Is it the ABS microprocessor that's choking, or the ABS machinery 
> (i.e., that which modulates the brakes)?
>
>
> Mark

Mark,
  You can look at the circuit here: 
http://ibmwr.org/r-tech/oilheads/ABS-II_low_voltage_modification/index.shtml
The low voltage during self-test in the control unit is what causes the fault.
Applying power AFTER the engine is started is the key to a successful ABS
initialization.  There are a couple of ways to do this.  The relay 
method described
above and/or using the load shed relay to supply the test 12V after cranking.
  It would require a very large cap to be able to supply 12V during 
cranking. :))

Mick