Tyre Pressure monitor. How much pressure loss before LOW?

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logiclee
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Tyre Pressure monitor. How much pressure loss before LOW?

Post by logiclee »

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
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cachaciero
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Post by cachaciero »

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 :-(

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Post by Homer »

On my 807 it's very picky.

One or two psi down is enough to set it off.
R9UKE
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Post by R9UKE »

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?
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Post by JohnD »

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.
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cachaciero
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Post by cachaciero »

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
2006 Toyota Prius T Spirit
2001 2.2 C5 Exclusive SE
1996 XM 2.1 TD Auto VSX
1995 XM 2.1 TD Auto SX died @ 140K
1987 CX 2.5 Gti Turbo II dead
1984 Ford Scorpio
1981 CX 2.4 Pallas Auto
Renault 21
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