XC90 T8 Brake Failure Warning

[Mefster]

Hi All

I’ve been a Volvo owner for 4 years but new to the forum. My 2020 (‘21MY) XC90 T8 has recently started showing the “Brake Failure Stop Safely” warning message on the dash. There doesn’t appear to be any change to brake performance and when the car is restarted the error message has cleared.

Bizarrely, it only seems to appear on exactly the same point on my drive home, about 200 yards from my house, no matter how long my journey has been. It’s a single track country lane, down hill with a rather uneven surface (not pot holed but subsided, which rocks the car a little. I wondered if it could be an issue with a sensor/connector somewhere rather than an actual brake issue.

There is also standing water on my road that has been present for about 6 months which I drive through daily. Only 3 or 4 inches deep. The error doesn’t appear to be triggered by that though.


I wondered if anyone else had experienced this problem? I thought with the strange nature of the problem, it may be better to ask the owners community rather than let my Volvo Dealer start blindly replacing parts!

Thanks in advance

[Whyman]

Is your brake fluid level low? Might be that the rough surface is enough to trigger the level sensor!

[Mefster]

I’ll check 👍

[Philip Fisher]

Originally Posted by Whyman

Is your brake fluid level low? Might be that the rough surface is enough to trigger the level sensor!

My thoughts also.

[Mefster]

Is it easy to access the reservoir to check levels and top up? Can’t find any information or videos online and the manual gives no info- advises the dealer should do it!

[wynnj]

If you do find that the level is low remember to check the brakes on each wheel; worn discs and pads will cause the level to drop.

[nu11eaf]

Originally Posted by Mefster

Is it easy to access the reservoir to check levels and top up? Can’t find any information or videos online and the manual gives no info- advises the dealer should do it!

The reservoir is behind the scuttle panel on drivers side, there is an access hatch that unclips to get at it, it is easy to check the level.

[Mefster]

Found and checked the reservoir- appears low (can’t see any fluid in the top reservoir).
Is it DOT 4 fluid I need to use or anything more specific/special?

[nu11eaf]

Originally Posted by Mefster

Found and checked the reservoir- appears low (can’t see any fluid in the top reservoir).
Is it DOT 4 fluid I need to use or anything more specific/special?

Do not fill the reservoir or when the pads are changed and pistons pushed back it will overflow, just add a small amount. I would you check your pads as they will be getting very worn.

[Mefster]

Originally Posted by nu11eaf

Do not fill the reservoir or when the pads are changed and pistons pushed back it will overflow, just add a small amount. I would you check your pads as they will be getting very worn.

Is there a separate brake pad wear warning light or does the Brake Failure Warning I’m seeing warn for pad wear by detecting the low fluid level?

I’m changing the wheels back to Summer wheels this week so I can check the pads.

Will any DOT4 brake fluid do or is there a specific one? Don’t want phone Volvo as I’m guessing they’ll ask me to bring it in!