Noise when auto hold disengages
 

When I have auto hold enabled on my XC60 (MY19 Momentum) and pull away from a standing start I have a kind of grinding noise.

It’s now been into the dealer 3 times to rectify (currently with them this week) and the latest attempt is fitting a new ‘pipe’ (don’t know what it is) supplied by Volvo. Feedback is that this has reduced the noise but not eliminated it and they are saying the noise is from the pump that engages and disengages the auto hold.

My response to the dealer today (over the phone as they still have the car) was that there must still be a fault if the noise is still there to which I was told ‘no, all XC60s make this noise’. I had a VW CC with auto hold and never had this kind of noise.

Does anyone else’s XC60 make this type of noise when auto hold disengages.

No noise from mine

Mine makes a strange little juddery noise, and a friends V90 does exactly the same. It’s not loud or obtrusive though, and has done it since day 1

As far as I am aware the auto hold is activated by electric motors which winds the pads onto the rear brake discs, not a pump.

The parking brake (rear wheels) is a motor but the auto hold (all 4 wheels) is by vacuum, same as your foot brake.

Mine does make a little noise when releasing auto hold but that's the pads letting go of the discs rather than the vacuum pump or release valve, every car I've driven with auto hold of various makes does the same so not worried by it.

I do have a bit of a noisy pump, someone on here likened it to a metal ruler rattling. I get the noise when I come off the brakes and the auto hold is holding the car. Seems other people have it too so I'm not bothered by it.

https://www.volvoforums.org.uk/showthread.php?t=283485

Auto Hold is the auto handbrake function that can be selected or deselected by the button directly behind the handbrake switch. It automatically applies the handbrake when the vehicle is braked to a stop and releases when throttle is applied. The handbrake consists of electric motors on the rear callipers that can be heard working, making a whizz kind of sound.

Hill Hold Assist is what stops the car rolling backwards when starting off uphill. This does not work on the handbrake, it works by stopping all four brakes releasing for only a second or two via the normal hydraulic system.

So which is the subject of this topic?

Not sure that's correct.

Autohold maintains the foot brake pressure when you come to a stop, releasing the held brake pressure when you press the accelerator - using servo pumps and vacuum valves. It does not engage the electric parking brake unless the car has been stationary for a while - seven mins?

The parking brake is indeed electric but it's separate from autohold and only work on the rear wheels. Autohold uses the brake servo pressure and works on all four. Two separate systems for safety.

I think you may be right, since the brake lights are still on when in auto-hold.
Annoying for the driver behind at night of course.
The brake lights go out when the parking brake is used.

So to answer the original post, autohold on my car makes a little noise when the brakes come off when moving away. It also makes a bit of a rattling noise when holding the car still sometimes.

Other people report the same behaviour so I think my car is fine and yours too maybe. A little noise from the pump/valves seems to be the norm. With tolerance variations I guess some are a little louder/quieter than others, plus everyone's hearing and sensitivity to tuning into these kind of noises is different.

This is correct but I think the handover time is ~3 mins.