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-   -   Tyre Pressure Monitoring Sensor (TPMS) puzzle (http://www.jeepgarage.org/f190/tyre-pressure-monitoring-sensor-tpms-puzzle-52743.html)

BobT 01-11-2013 06:53 AM

Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
My Laredo has as standard, four 18" alloy wheels mounted with 265/60R18 tyres each with a TPMS. There is an 18" steel spare of the same width but mounted with a 245/60R18 tyre and no TPMS. The TPM system in the Laredo is the simplistic version. As I understand it and please correct me if I'm wrong, if the spare was to be replaced with a full sized alloy wheel with a TPMS, there would be no problem because the TPM system monitors rotating wheels only. If this is the case, it's good because it allows a five wheel rotation. This is probably what I'll be moving towards as soon as I find another alloy wheel.

Now the puzzle. If I were to have a trailer mounted with wheels identical to those on the Jeep and the wheels were fitted with the Mopar TPMSs, would the TPM system monitor the trailer wheels as well? I suspect not but who knows. If the system is such that only rotating tyres transmit and then only when underinflated, then it wouldn't matter how many wheels there were. I guess we will have to wait until we know exactly how the system works or until someone tries it. I suppose I could ask a dealer:lol::lol::lol:

allypally 01-11-2013 02:52 PM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
The TPMS has the capacity for 4 readings only, and they will be effected by the distance from the Transmitter's in each tyre to the receiver. You will probably find that the spare, when stowed away, is out of range from the receiver.
I would also think that any transmitters which have been installed on trailer tyres are also out of range.
My former car had a car computer on which I installed some TPMS software and TPMS transmitters in the tyres. I was having difficulty in getting the correct location for the receiver antenna in order that I could receive the updates from each tyre. The range was very sensitive. By the way, in that system, I was able to monitor all tyres, including the spare. Why Jeep limited the TPMS to exclude the spare is another mystery that shows their mind set limitations.

John47 01-11-2013 06:27 PM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
It seems you can have a sensor fitted in the spare...but the system apparently only handles 4 sensors. As far as I can determine each sensor can transmit and receive to the WIN and after a "key on" cycle they will transmit a reading approximately 1 per minute at speeds over 24k.
The system has learned the location of each sensor at factory install. Because the sensors only transmit when rotating, possibly this would preclude information from a static spare.

You've probably checked out this Jeep Grand Cherokee WK2 - 2011 Grand Cherokee Tire Pressure Monitor System

My van tyre monitoring system is me.......checking the van tyres in the mirror regularly - cheap - and so far it has worked. Fingers x.
I have seen aftermarket systems used on vans and trailers and their owners have sung the praises.

BobT 01-12-2013 02:12 AM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
Great find John! I should have looked harder. I can find only one part number for the TPMSs so it seems both the basic and the premium systems use the same sensor. So 5 wheel rotation is possible. However, reading the spare pressure is not possible while ever it isn't mounted and rotating. To me, the link implies that at least 5 and possibly more wheels can be monitored but non-rotating wheels do not transmit so will not give a reading. So as Allypally says, it is a matter of transmission range as to whether trailer wheels are picked up. It seems the basic system uses the single omnidirectional wireless ignition node (WIN) to pickup the TPMS transmissions whereas the premium system uses a number of directional pickups around the vehicle so as to be able to identify the location of each sensor.

I note the comment in the link that despite using the same sensors, it is not feasible to upgrade the basic system... bugger!

John47 01-12-2013 05:26 PM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
I used the WK2 Jeeps site a lot while waiting the six months for ours to arrive and became pretty familiar with its contents.
As far as I know it is put together by Milous - a great source of quality information.

John47 01-12-2013 11:12 PM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
Also look here for part numbers - at least applicable to the US...(post 6)
http://www.jeepgarage.org/f109/tpms-part-52572.html

GlennR 01-15-2013 02:17 AM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
Slightly off subject but right on cue, picked up a tech screw in my offside rear today. The EVIC threw up a warning showing all four wheels and the tyre with the slow puncture flashing at 1.8 Bar. Sorry guys but the child in me never ceases to be amazed by the technology on this machine. $30 later and all is well, but the repair guy mentioned there's not much left on the Kumho's at 17500kms......off to view the tyre threads. Four Cooper Sports Zeon's might be on the cards before June 30:thumbsup:

BobT 01-16-2013 03:56 AM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
Quote:

Originally Posted by GlennR (Post 739842)
Slightly off subject but right on cue, picked up a tech screw in my offside rear today. The EVIC threw up a warning showing all four wheels and the tyre with the slow puncture flashing at 1.8 Bar. Sorry guys but the child in me never ceases to be amazed by the technology on this machine. $30 later and all is well, but the repair guy mentioned there's not much left on the Kumho's at 17500kms......off to view the tyre threads. Four Cooper Sports Zeon's might be on the cards before June 30:thumbsup:

Good luck with the tyre hunting. Be aware that not all Zeons are LT construction. That may not be an issue for you but if it is, then the selection is severely limited in both 18" and 20".

just4fun 01-28-2013 12:20 AM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
When changing tryes do the rims need to go back to the original position or are he sensors smart enough to know which new position that are?

allypally 01-28-2013 05:39 AM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
The rims can go in any position

just4fun 01-28-2013 05:56 AM

Re: Tyre Pressure Monitoring Sensor (TPMS) puzzle
 
Thankyou


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