Tyre pressure sensors

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
Stempy
Posts: 1626
Joined: 26 Feb 2004, 23:21
Location: Cloud Cuckooland
My Cars: C5 V6 Mk1 assainated by wife
Renault Kangoo 1.6 auto, tarted up and remapped
Still missing the Xantia V6
Not missing the AX
Contact:

Tyre pressure sensors

Post by Stempy »

I know they are fitted with a long life lithium cell but is this potted in or can it be replaced?
It infuriates me to be wrong when I know I'm right

Lexia ponce

http://perception.dyndns.biz/~avengineering/index.htm
User avatar
tco_tm
Posts: 22
Joined: 21 Jan 2014, 12:32
Location: Poland
My Cars:

Re: Tyre pressure sensors

Post by tco_tm »

Backside of sensor is filled with some kind of glue or synthetic resin. You can replace valve stem, but I believe that getting access to the battery without damaging sensor internals or its housing is impossible.
User avatar
qprdude
Posts: 1754
Joined: 06 Apr 2012, 18:56
Location: Woking, Surrey
My Cars: Renault 5 TS, Renault 14ts, Citroen C5 Mk1, Renault Clio sport, Renault Laguna Privilege. Citroen C5 X7 Exclusive. Citroen DS5 D/sport . And around 25+ other brands from Morris Oxford to S Type jag and most things between.
x 10

Re: Tyre pressure sensors

Post by qprdude »

I was told the battery life is 5 years, but could be much longer.
Yes, the CR battery would appear to be embedded in resin. I think it lies on the + terminal plate, with a - terminal on top and is then covered in resin. the Resin will be set hard, so in theory, it could be broken out using a small screwdriver and taking care not to break the negative terminal plate. Once the battery is exposed, the negative terminal could be gently bent back and the battery prized out. With a bit of a clean up a new battery could be fitted and you can buy those little resin hypo thingy where the stuff hardens on contact with air.

This is mostly supposition and theoretical, but for someone with determination, it could be done. In answer to the question though......no, the battery is not meant to be replaced. I suspect the resin is to ensure the battery stays put when subject to the forces of the wheel rotation at high speeds, over bumps etc.

An "exciter" would still be needed to kick start the sensor, and probably a lexia session to recognise it. Incidentally, my sensors were replaced FOC by Citroen after two of them failed even though the car was well out of warranty. I see the point of your question though. They are bloody expensive to replace!
Rick.

2013 Citroen DS 5 D/Sport
2007 Renault Clio Campus sport. 1.2l

Sometimes the change doesn't work.
dnsey
Posts: 1538
Joined: 20 Oct 2004, 01:39
Location:
My Cars:
x 19

Re: Tyre pressure sensors

Post by dnsey »

There are videos on the Net showing battery replacement, so it seems to be a possibility.
I'm not sure that an exciter would be needed if the same sensor is refitted - from the car's point of view, wouldn't it be the same as removing the wheel for a while, then refitting it? If care is taken to ensure that the sensor is never completely powered down, I suspect that even a tired battery might keep it 'alive' long after it stops transmitting.
User avatar
qprdude
Posts: 1754
Joined: 06 Apr 2012, 18:56
Location: Woking, Surrey
My Cars: Renault 5 TS, Renault 14ts, Citroen C5 Mk1, Renault Clio sport, Renault Laguna Privilege. Citroen C5 X7 Exclusive. Citroen DS5 D/sport . And around 25+ other brands from Morris Oxford to S Type jag and most things between.
x 10

Re: Tyre pressure sensors

Post by qprdude »

Good point, but surely if you removed the battery, the signal is lost?
Not sure how it works really, but surely the sensor is powered down when the old battery is taken out.

I looked at the old sensors when they were out, and I could see resin but no battery. The guy said he had never seen a battery changed in a C5 sensor, but as I said, it's just a CR battery embedded in solid goo. Remove the road-wheel, remove the sensor, remove the goo, remove the battery replace the battery and the goo, refit the sensor and wheel.
Personally, I doubt if I would bother, because I don't have the patience, and would probably bugger something up by rushing.

I noticed some reasonably cheap ones on Ebay, supposedly to fit the C4, C5, Pug 408 etc.
Rick.

2013 Citroen DS 5 D/Sport
2007 Renault Clio Campus sport. 1.2l

Sometimes the change doesn't work.
dnsey
Posts: 1538
Joined: 20 Oct 2004, 01:39
Location:
My Cars:
x 19

Re: Tyre pressure sensors

Post by dnsey »

Yes, you'd have to connect an external supply whilst replacing the battery.
vborovic
Locked user account
Posts: 1750
Joined: 31 Oct 2013, 17:07
Location: Somewhere
My Cars: A used Citroen
x 27

Re: Tyre pressure sensors

Post by vborovic »

But we don't know for which state of the sensors Stempy is asking, maybe they're already dead (the battery)? If it would be battery replacement due to prevention, then it would make sense of doing it, but if the senors is already done, and if it loses it's signal, battery replacement possibly won't make any difference ...
Stempy
Posts: 1626
Joined: 26 Feb 2004, 23:21
Location: Cloud Cuckooland
My Cars: C5 V6 Mk1 assainated by wife
Renault Kangoo 1.6 auto, tarted up and remapped
Still missing the Xantia V6
Not missing the AX
Contact:

Re: Tyre pressure sensors

Post by Stempy »

Well heres the thing....My C5 tells me that one wheel sensor is missing. I have a spare set of wheels with sensors fitted and when they are on the car it still tells me there is one sensor missing. I was under the impression that the sensors have to be matched to the car using a Lexia so I dont really know what is going on. I guess I will have to bite the bullet and buy a Lexia and start interrogating, it might throw a light on various other little problems as well.
It infuriates me to be wrong when I know I'm right

Lexia ponce

http://perception.dyndns.biz/~avengineering/index.htm
vborovic
Locked user account
Posts: 1750
Joined: 31 Oct 2013, 17:07
Location: Somewhere
My Cars: A used Citroen
x 27

Re: Tyre pressure sensors

Post by vborovic »

Let me see if I understood that correctly. You have 1 set of wheels on the car with sensors, and another set of wheels as a spare, also with sensors? I'm not sure about the first gen C5, does it show you the location of the missing sensor, or just says one is missing/flat/whatever ... ?
User avatar
tco_tm
Posts: 22
Joined: 21 Jan 2014, 12:32
Location: Poland
My Cars:

Re: Tyre pressure sensors

Post by tco_tm »

There are 9 slots for tire pressure sensors in C5 I / II. You can enter ID numbers of summer and winter sets and also a spare wheel. Each wheel has its own receiver in wheel arch, so punctured tire is recognized by its location. When changing tires with sensors and rotating them to equalize their wear, I noticed that it takes same time until computer recognizes their new positions. So, sometimes location detection may be misleading.

If you are getting information of missing sensor always in one location, probably not sensor but receiver is damaged.

BTW, speaking about TPMS, I am not sure if new sensors always have to be entered into configuration of vehicle by Lexia. I suspect it just speedups recognition / initialization of readings. I am telling this, because configuration of sensors seems to be a little bit awkward (can't find better word)... When rotating tires, even if you change IDs of appropriate sensors in slots (slots corresponds to specific locations) computer overrides those proper assignments and shuffle them around for a while. Finally, after few days everything seems magically get to the right places. Another example is situation, when I asked dealer to configure my four new sensors (using special tool it can be done without removing tires and reading sensor IDs from their housings). There were some problems with activation of one sensor – it was not sending its ID to receiver. I left service with only three of them configured, but during my ride home the missing one was somehow added and wheel appeared as inflated.
wheeler
Posts: 6848
Joined: 21 Sep 2002, 19:07
Location: United Kingdom
My Cars:
x 717

Re: Tyre pressure sensors

Post by wheeler »

The mk1 & 2 C5 TPMS's are totally different, the mk1 doesn't have its own ECU, its all managed by the BSI & the receiver for the wheel sensors is integrated into the Com2000 unit, This system cant differentiate which sensor is which, You still need an exciter tool to program the wheel sensors along with Lexia.
The Mk2 C5 system is a bit more complex, it has its own dedicated ECU with integrated RF receiver. The things in the wheel arch that tco_tm mentions are not receivers but in fact exciter modules that force the sensors to transmit these are only fitted in the front wheel arches, there are no modules for the rear wheels. With these it can differentiate between front & rear sensors. The tyre pressure detection ECU then scans the vehicle speed, steering wheel angle and tyre acceleration data to differentiate between the right and left hand wheel transmitter modules. If you swap the wheels around the system will re learn the positions of any already programed sensors
User avatar
tco_tm
Posts: 22
Joined: 21 Jan 2014, 12:32
Location: Poland
My Cars:

Re: Tyre pressure sensors

Post by tco_tm »

wheeler, thanks for clarification +1. I deepen my knowledge and hopefully understood why sensors locations could be mismatched for a while after rotating tires and why attempts to enter theirs IDs to corresponding slots does not always work.
User avatar
qprdude
Posts: 1754
Joined: 06 Apr 2012, 18:56
Location: Woking, Surrey
My Cars: Renault 5 TS, Renault 14ts, Citroen C5 Mk1, Renault Clio sport, Renault Laguna Privilege. Citroen C5 X7 Exclusive. Citroen DS5 D/sport . And around 25+ other brands from Morris Oxford to S Type jag and most things between.
x 10

Re: Tyre pressure sensors

Post by qprdude »

Don't know how the X7 ones are controlled, but they are wheel specific, with a warning showing which tyre is deflated. My new ones had to be "enabled" by a hand held wireless exciter, then the lexia was hooked up for some other reason to do with coding them to the car. I don't know if my spare has one or not.
Not tried rotation the corners, so couldn't say if the X7 system can "learn" after a sensor is moved. As long as they keep working, I'm kinda glad to stay well clear. 8-[
Rick.

2013 Citroen DS 5 D/Sport
2007 Renault Clio Campus sport. 1.2l

Sometimes the change doesn't work.
Stempy
Posts: 1626
Joined: 26 Feb 2004, 23:21
Location: Cloud Cuckooland
My Cars: C5 V6 Mk1 assainated by wife
Renault Kangoo 1.6 auto, tarted up and remapped
Still missing the Xantia V6
Not missing the AX
Contact:

Re: Tyre pressure sensors

Post by Stempy »

If an exciter is needed on the new system then it would suggest that the sensors dont need a battery and operate in a similar way to anti theft chips or dog/cat ID chips where the information is transmiited after being activated by a scanner.

I know that on my old system there is a centrifugal switch built into the sensors that turns them on once you are moving, and it only gives the sensor missing warning after about 15-20mph. I guess if you need to allocate the sensors to the vehicle this would be done at a standstill so I assume that is why an exciter is needed to reprogramme even the old types, which means a visit to a dealer even if you have a Lexia.
It infuriates me to be wrong when I know I'm right

Lexia ponce

http://perception.dyndns.biz/~avengineering/index.htm
wheeler
Posts: 6848
Joined: 21 Sep 2002, 19:07
Location: United Kingdom
My Cars:
x 717

Re: Tyre pressure sensors

Post by wheeler »

The mk2's still have batteries in the sensors, citroen estimate the battery life at 10 years.
I assume the animal chips & transponder chips don't need batteries because the range is so short, not usually more than an inch, the wheel transmitters are about a foot & a half away so I imagine they would still need a power supply.
Post Reply