Parking brake fault, Cayenne

[NickGS]

Hi.
I have a Cayenne 2019 turbo s e-hybrid that is intermittently giving an electronic parking brake fault, followed by an ACC fault. Does anyone have experience with similar?

I am considering whether it may be time to renew the battery. When the engine is on, the voltage reads around and above 13 volts. Are there any devices you would recommend having to occasionally test the health of a battery?

[The Wookie]

I had this with mine, apparently it’s common and it just needs to go through the right reset/recalibration cycle.

Porsche dealer didn’t fix it when they tried but took it to nine excellence in Horley and they cured it somehow.

[NickGS]

Thanks, Wookie. This was helpful.
I am driving to the Alps in a few weeks, hence why asking around for any experience with similar. The car is booked in with a Porsche dealer. Based on what you said, I will call them to gauge whether they know what to do re calibrating the hand brake motor, or I will take it to a specialist. Thanks to you I have a recommendation. I called Porsche Assistance, and the guy said the same as you, i.e., it needs to be recalibrated.

[The Wookie]

No probs at all

I wouldn’t worry too much about it if the fault comes back afterwards, these EPB systems are engineered to a pretty tight specification to homogenise them across applications and make them easier to integrate with the ABS/ESP, to the point of having to fall within certain actuation time and power draws to avoid throwing a fault.

Evidently it’s a bit marginal to those specs as it comes so it’s almost certainly nothing that will actually affect its performance, it’s probably just taking a bit longer than it should to engage or one side is engaging a bit quicker than the other.

[NickGS]

In line with what you say, the fault does seem to show when the sound of the motor winding on one wheel happens to be shorter than the normal duration, say, 3s vs 5 s.

I was able to bring forward the booking; so, giving me chance to use the car a little more and identify any residual errors before the big trip.

[NickGS]

To conclude, it needed recalibration after general wear. Hence, I suspect this will be required eventually on all four wheels at various times during the life of the car. The cost was approximately £350 for one wheel.

[The Wookie]

Funny enough I actually learnt more about this a few weeks back when the Porsche dealer went to charge the old man for adjusting the handbrake, which I thought sounded like total bks

Turns out, no the EPB drum brake isn’t self adjusting so it does actually need wheels off doing manually!

You take the rear wheels off, plug the car into the diagnostic, it runs a cycle and works out the air gap between the shoes and the drum. Then the mechanic adjusts the drum brakes by poking a screw driver through an inspection hole like you would on a bloody 1950’s car and runs the test again to check the air gap is within the allowed margin

350 quid sounds pricey for that process, it sounded like an hours chargeable work maximum for both wheels

[NickGS]

A general inspection was done on the car that also identified a rear wiper blade in need of replacing. They quoted £144. I opted to do it myself, found a Bosch part online for £9, it was posted the next day, and took me seconds to install.