[928uk] Differential control off warning

[Richard Armstrong]

Hi Jan-Willem
That means your PSD pump is not working - not keeping the system at 
pressure so it shuts itself down.
It could be the brake fluid level is low (but that would be because of a 
leak anyway) or, more likely, the pump has stopped pressurising the 
fluid. It is a spring and ball bearing rotating in an eccentric case and 
when the fluid gets old and gets some moistue in there it gets 
crystaline and jams the pump.
It could also be the accumulator leaking - it is very high pressure and 
not to be messed with if you don't know what you are doing!
Richard

On 06/02/2023 15:05, Jan-Willem Labeij wrote:
> A red differential control off warning is showing after start up.
> 1990 S4, what does it mean?
> Cheers,
> Jan-Willem
>
> Sent from my iPad

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