[928uk] Differential control off warning

[Paul R Smith]

I would strongly recommend getting the fault code read out, it will save 
you time, but bear in mind that a fault code for insufficient pressure 
could be correct, or it could be the pressure switch which is faulty. 
The chances are that the brake fluid is very old, so everything will 
need a good clean out/bleed through.

Smiffy

On 06/02/2023 15:28, Richard Armstrong via 928uk wrote:
> 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
>