"Brake failure stop safely" and limp mode - see photo

[bugeye]

Check battery for proper voltage, power. These Volvo's are sensitive to a failing battery and/or poor electrical contacts at battery and/or ground wire connections.

[whatnoise]

My 2004 Volvo V70 has a similar issue. First did it at 80K miles about 5 years ago and has probably happened another 6-8 times since then. Now at 182K miles.

First there's a jolt as the transmission drops into limp home mode and then in varying orders I get warnings about engine service required, transmission service required, brake failure stop safely, loss of gear indication in instrument panel, loss of water temp, loss of rev counter, loss of speedo, loss of gear position lights on gear selector, loss of cruise control. Two times after this happened I took it to an independent dealer who said he couldn't really help because every fault code possible was logged in the fault store.

More often than not a couple of resets by turning the ignition off clears the fault. Occasionally some of the warnings are persistent for a little longer. Twice it wouldn't start (turned over but nothing more).
I've got it into my head that it's probably a fault with the engine and transmission ECUs because once when it wouldn't start I wiggled them about a bit and everything was OK. Corrosion on pins? But could be a coincidence.

[RJW75]

I have exactly this issue with my 2005 D5. 'Brake Failure - Stop Safely' message on dash and all dials go down to zero, warning lights, limp home mode, wont start for a time etc. etc.

Took into Volvo specialist garage (not main dealer) got fault codes read, and there were loads of codes seen.
All codes were reset, and one remained - brake position sensor.
Changed that sensor and the car was ok - hooray! it was fixed.
Then 2 days later it happened again!! Damn. Back to square one.

Took back to garage - and they now cannot conclusively find a cast iron problem to sort out. Could be this, could be that. Not sure what to do now as I can see its going to get expensive.

[ts72]

2005 model D5 manual with a similar problem - on start up the same error message comes up and no speedo, left stalk dial options (range/mpg etc) or cruise control. However no loss of engine power or braking power and can drive it. If I leave the car running from starting for a minute or two, the warning goes out. Switch off and restart, no warnings and the speedo and stalk options (range/mpg etc) work, as does the cruise control. It seems more prone to it in cold/wet conditions.

I've connected VIDA and the codes point to a communication error between the CEM and the Brake Control Module on mine.

[SwissXC90]

Originally Posted by ts72

I've connected VIDA and the codes point to a communication error between the CEM and the Brake Control Module on mine.

Check physical connections for dirt and water ingress, especially on the CEM.
If you find any signs of water or corrosion in the CEM, then get it repaired ASAP.

Volvo will only replace the CEM with a new one, but there are places that can repair the corrosion...

[ts72]

Originally Posted by SwissXC90

Check physical connections for dirt and water ingress, especially on the CEM.
If you find any signs of water or corrosion in the CEM, then get it repaired ASAP.

Volvo will only replace the CEM with a new one, but there are places that can repair the corrosion...

Well aware of all that, my options, the condition of the related components having removed and inspected them myself, and more thanks. I was merely pointing out similar symptoms as a possible route of investigation for the OP.