Hello I have recently bought a CR170 Elegance Combo and one thing kinda baffles me. How does the automatic tyre pressure thing work. When I press the button the sign on the dash comes on and then goes off what does it mean, how do I relate to the information, is the tyre pressure correct, do I need to check it etc etc. Any help would be appreciated. Thanks Roy

Edited 8 December, 201114 yr by Roy&Val

Hi there, from memory

When you press the button you are effectively resetting the system.

When the pressures deviate from those values that were present when you reset the system it will alert you.

Hope this helps

Cerys

It works by constantly monitoring the wheel rotation between all four wheels using the ABS sensors on each wheel.

If a tyre starts to deflate/punctures, that tyre will rotate more than the other three. The system monitors this and will set the warning lights off on the dash

It works by constantly monitoring the wheel rotation between all four wheels using the ABS sensors on each wheel.

If a tyre starts to deflate/punctures, that tyre will rotate more than the other three. The system monitors this and will set the warning lights off on the dash

Also pretty accurate. I think it can detect about 3-4 psi loss from a tyre.

Note that tyre speed is compared per-axle, so that if both wheels on the same axle deflate at the same rate the system will not detect the change.

when rotating tyres.. remember to reset else you'll get the warning

it is also just a monitor, it does not display the current pressures at all and only monitors for differences in wheel rotation via the ABS sensors.

Note that tyre speed is compared per-axle, so that if both wheels on the same axle deflate at the same rate the system will not detect the change.

I'm not sure that's completely true. The sensors are actually monitoring changes to the tyre rolling circumference, which will only depend on pressure (which is also temperature related). Rotational speed it not a constant and depends on road speed and tyres on the same axle will rotate at different speeds around corners etc. It will sense a change of a few psi as we found out on my wife's A-Class which had a puncture and the deflation wasn't noticeable with the naked eye. A very useful tool but you do have to remember to reset the system every time you've added air to a tyre.