Yes I did... Whats your point ?
Yes I did... Whats your point ?
sierrafery
Well-Known Member
My point is in that post. Are you sure that your pump is working well?
Phanc60844
Member
I'm still at a total loss why you would think that low fuel pressure would throw a driver demand high fault. There is absolutely no correlation between fuel pressure and pedal position so why would the ECU link the two? It doesn't even know what the fuel pressure is!
sierrafery
Well-Known Member
Read again post #7... i didnt think about the reasons, i've seen this happenning myself and happened to others too but i know how a fault code protocol works and it's not very uncommon that an ECU to throw a wrong fault code if some conditions for it are met even if those conditions are not 100% spot on
if you apply the same logic the ECU doesnt know the fuel pressure but it calculates the IQ which must have a result in rpm so if the fuel pressure is low the IQ will suffer so the rpm will be different than the ECU expects at a certain throttle position hence it declares a driver demand fault... i dont know the real reason... just remember that there are cases when it happens in reality.
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https://www.aulro.com/afvb/discovery-2-a/112980-td5-driver-demand-error.html#post1329071
You may be correct SF. A quick search finds others have had demand faults pop up, for other issues.
You may be correct SF. A quick search finds others have had demand faults pop up, for other issues.
NPG
Well-Known Member
In my opinion, driver demand issues are always triggered by the accelerator pedal (hence the fault description) but can involve any subsystem responsible to deliver the requested torque, be it injectors, inlet manifold pressure, air flow, turbo, fuel quantity, etc. In short, anything that will affect the intensity of the combustion will impact the downward force on the piston and therefore the torque at the crank and thus engine speed and power delivered by the stroke. So I think it is safe to conclude that this fault is registered when the engine speed does not align with the expected rpm curve as calculated by the ECU on the basis of the the driver's accelerator input and other parameters.
