Tyre Pressure monitor. How much pressure loss before LOW?

logiclee · Unread post by **logiclee** » 08 Jun 2010, 21:16

OK I'm lazy and it's raining.

So just reading through the handbook for my C5 and a qusetion popped into my head about the Tyre Pressure monitors.

Citroen don't tell you a pressure just that the Tyre pressure is "OK".

So my question is what tolerance does the system give? My normal tyre pressure is 35psi at what pressure will it alarm?

If no one knows I'll do a little trial this weekend.

Cheers
Lee

cachaciero · Unread post by **cachaciero** » 08 Jun 2010, 22:44

The trigger level is programmed into the BSI this would allow the value to be changed depending on tyres used. Can't find any specific data for any tyre though

cachaciero

Homer · Unread post by **Homer** » 09 Jun 2010, 17:22

On my 807 it's very picky.

One or two psi down is enough to set it off.

R9UKE · Unread post by **R9UKE** » 09 Jun 2010, 18:51

I didn't even know my C5 had tyre pressure monitors until I was driving along the motorway one day and it said "One pressure sensor missing". It disappeared straight away - must've lost contact for a brief minute.

Well I had the car for six months and never got any warnings... I did experiment in a service station - deflated the tyre completely to check for a warning; nothing - perhaps the car needs to be moving?

JohnD · Unread post by **JohnD** » 09 Jun 2010, 18:52

As my towing trips are usually of several hundreds of miles, I raise the rear pressures up to 3 bar. After I arrive I reduce the pressures again. I've often wondered why the pressure warning didn't trigger when the air was let out, but eventually I decided the system had been deactivated. But then I recently picked up a screw through the tread. First time I'd seen the warning in 5 years.

cachaciero · Unread post by **cachaciero** » 09 Jun 2010, 19:56

R9UKE wrote:I didn't even know my C5 had tyre pressure monitors until I was driving along the motorway one day and it said "One pressure sensor missing". It disappeared straight away - must've lost contact for a brief minute.

Well I had the car for six months and never got any warnings... I did experiment in a service station - deflated the tyre completely to check for a warning; nothing - perhaps the car needs to be moving?

It does, above a certain speed 20Km/hr I think the system samples pressure every few seconds or so stationary it samples about once every thirty five minutes or so. These figures are not gospel but it is the general way the thing works at least for the Mk1.

cachaciero