XC70 AWD Diesel (2014) - intermittent warning signals

[Stephen Louw]

Volvo XC60 4WD (2014 model) electrical faults
About 6 months ago, while driving, a warning light on the dashboard came on: "ABS Failure". Our service station engineer said that it was probably some dirt on the monitor. The message disappeared for a number of months.
Then I noticed slight juddering of the brakes about 3 months ago.
Then the message "ABS Failure" came on while driving a long distance. The message was not constantly displayed – it would sometimes come on after driving more than 100 miles continuously and may disappear while driving. It did not come on when braking.
Then the message "ABS/ESC disabled" appeared – again intermittently for no reason.
Then a message indicating that my one "tyre flat – Recalibrate Tyre pressure". On checking, the tyre pressure was not low at all.
Then, most recently a message: "City Safety Service required" – this is now constantly on display.

Actions to date:
A Volvo service garage engineer in Italy did an electrical diagnostics test and said the right rear wheel ABS sensor was defective and should be replaced. But I found this unlikely to be correct, since it would not account for the other messages (particularly that a front wheel was low in pressure).
I have ‘Reset Factory Settings’ but nothing happened.
I have reset Tyre Monitor Calibration – but nothing happened.
It seems to me that this is not a sensor problem but something wrong with the Central Electronic Module – am I right? (I note a thread on VOC regarding water ingress sometimes causing problems with the CEM and that “Volvo Diagnostics do a refurbished CEM for £260.00 which is plug and play”.)
Please advise. (I am not particularly ‘technical’ unfortunately!)

[emtor]

I have read, on the swedish volvo forum, that a right rear wheel sensor fault is often indicative of bad soldering in the ABS unit itself. Not the hydraulic part of the unit, but the electronic part.

[emtor]

Don't forget that the electronic part of the ABS unit,-if you buy a new one or second hand, must be coded to your car to make it work, either at the volvo dealership or with VIDA.

[Stephen Louw]

Thanks Emtor - I would never have thought of the encoding issue!
Regards
Stephen

[Sotosound]

Originally Posted by Stephen Louw

Volvo XC60 4WD (2014 model) electrical faults
About 6 months ago, while driving, a warning light on the dashboard came on: "ABS Failure". Our service station engineer said that it was probably some dirt on the monitor. The message disappeared for a number of months.
Then I noticed slight juddering of the brakes about 3 months ago.
Then the message "ABS Failure" came on while driving a long distance. The message was not constantly displayed – it would sometimes come on after driving more than 100 miles continuously and may disappear while driving. It did not come on when braking.
Then the message "ABS/ESC disabled" appeared – again intermittently for no reason.
Then a message indicating that my one "tyre flat – Recalibrate Tyre pressure". On checking, the tyre pressure was not low at all.
Then, most recently a message: "City Safety Service required" – this is now constantly on display.

Actions to date:
A Volvo service garage engineer in Italy did an electrical diagnostics test and said the right rear wheel ABS sensor was defective and should be replaced. But I found this unlikely to be correct, since it would not account for the other messages (particularly that a front wheel was low in pressure).
I have ‘Reset Factory Settings’ but nothing happened.
I have reset Tyre Monitor Calibration – but nothing happened.
It seems to me that this is not a sensor problem but something wrong with the Central Electronic Module – am I right? (I note a thread on VOC regarding water ingress sometimes causing problems with the CEM and that “Volvo Diagnostics do a refurbished CEM for £260.00 which is plug and play”.)
Please advise. (I am not particularly ‘technical’ unfortunately!)

Is your car an XC60 or XC70?

[Goldfish888]

My xc70 2016 has similar false tyre pressures warning too .the dash warning appears to come up after driving in a stop/ go nose to tail traffic for a while. Each time I checked the tyre pressures and they were normal. I asked my local independent Volvo specialist and the impression given I got was the application is temperamental. I now just reset the warning routinely and live with the imperfection

[Stephen Louw]

Problem solved.
I took the car to my local (non-Volvo) garage (Mickley Garage in Northumberland). On showing Barry the printout from the Forum, he looked sceptical. He noticed that a front tyre was wearing very unevenly. He replaced the front tyres and re-aligned the wheels.
All the warning messages disappeared and the car is behaving very well.
Thanks for your input anyway.
Stephen Louw