Deflation Warning - ST

**FoxtrotGolfXray 5.0** · 09-12-2014, 10:06 AM

Had an interesting one the other day. was on my home from work when the Deflation Warning appeared. As I had just pulled into a town on the way home, I diverted to the nearest servo and checked the tyre pressures.

Found the front right to be a few psi lower than what I run them at, but I thought the Deflation Warning was not sensitive enough to pick up variations of only a few psi.

Put some air in the tyre, rest the Deflation Warning system at the new pressures and have not had a problem since.

Figured it must have been a instrument error.

Anyone else experienced this?

Craig H

**DJM83** · 09-12-2014, 10:25 AM

Mine has done the same.

**FoxtrotGolfXray 5.0** · 09-12-2014, 11:22 AM

Quote:

Originally Posted by DJM83

Mine has done the same.

Thanks.

Has/does it do it often? And does it still do it? I'm guessing that you haven't identified a cause yet?

eb falcon gl · 09-12-2014, 11:46 AM

Mine has done it twice and both times only one tyre has been down a few psi.
The first time it happened i thought something was wrong with it because i was under the impression that it meant that the tyre was dead flat. I got out and checked it and no tyre was obiviously flat

**DJM83** · 09-12-2014, 04:54 PM

Only does it when the tyre has dropped a cpl psi. Always the same though, it has never been more than about 4 psi when it has gone off

EVL BOS · 09-12-2014, 10:25 PM

Mines done it a few times. From meomory if the psi drop below 4psi lower than the set psi the alarm will go off

Mulga · 10-12-2014, 06:41 AM

Quote:

Originally Posted by EVL BOS

Mines done it a few times. From meomory if the psi drop below 4psi lower than the set psi the alarm will go off

Same.

**FoxtrotGolfXray 5.0** · 10-12-2014, 01:55 PM

Thanks guys!

Not sure where I picked it up (handbook, maybe?), but I was certainly under the impression that the Deflation Warning system did not activate with pressure variations of relatively small pressure deviations.

With my experience and your individual experiences as well, it would appear that my understanding was indeed incorrect.

Thanks again for the input.

Craig H

gassed250 · 12-12-2014, 11:37 PM

I want to know how it sensors that there is a deflated tyre, as there's no pressure sensors in the wheels

bugmesome · 13-12-2014, 10:03 PM

Quote:

Originally Posted by gassed250

I want to know how it sensors that there is a deflated tyre, as there's no pressure sensors in the wheels

Could be mistaken, but I believe it's the ABS sensor that detects that the wheel is rotating slightly slower (faster?) than the others, thus must be a bit deflated.

gassed250 · 14-12-2014, 12:12 PM

Quote:

Originally Posted by bugmesome

Could be mistaken, but I believe it's the ABS sensor that detects that the wheel is rotating slightly slower (faster?) than the others, thus must be a bit deflated.

Ah yep I thought it must have been something along those lines

Cashie · 14-12-2014, 12:44 PM

Are there definitely no TPMS sensors in your wheels?

gassed250 · 16-12-2014, 04:24 PM

Quote:

Originally Posted by Cashie

Are there definitely no TPMS sensors in your wheels?

Nope

when I had new wheels fitted I used the original tyres and I was surprised that there were no sensors in them

pajoda · 20-12-2014, 10:03 AM

Warning has come on for me about three times, pressure has been fine. Just reset and its fine again.

Bradw77 · 23-03-2015, 11:44 AM

Had this happen on the way to work this morning, got to work and found the front right tyre flat. Now I have to decide whether I change it myself or get RACV to come out to work and change it for me.

LeadFoot81 · 23-03-2015, 02:24 PM

Quote:

Originally Posted by DJM83

Only does it when the tyre has dropped a cpl psi. Always the same though, it has never been more than about 4 psi when it has gone off

I've had the same experience (once) in my Fiesta ST.

mik · 01-04-2015, 11:29 PM

once your tyre is flat , the damage is probably done, big chance your tyre will end up knackered if you drove on it any distance,

also if you ignore the tyre pressure warnings and drive on it spongey or with very low inflation pressure its possible to do damage to the rim and then theres always a possibility if you happen to be going around a bend and the tyre has low pressure in it, it can become unseated from the rim and you could end up on your roof .......... ask me how i know this

.

chrisorm · 22-05-2015, 12:55 PM

Had ours go off last week, and upon checking the pressures, one was down to 25psi.

Was curious to see if I had reset it properly, page 11 of this PDF seems to explain it accurately - it's definitely based off rolling circumference calculated by the ABS sensor:

http://www.fordservicecontent.com/pu...N13FOCqg1e.pdf

Although I reset it while driving, so should remember to reset it tonight.