Jeep Wrangler Forum banner
1 - 20 of 76 Posts

·
Registered
Joined
·
273 Posts
Should be in all five or you'd have problems with the TPMS when you do a five tire rotation. I know the 2012s have them in all five.
 

·
Registered
Joined
·
28 Posts
I specifically asked when I purchased my 2013 Unlimited Rubicon a week ago. I was told there is a TPMS in the spare as well.

Mike K.
 

·
Registered
Joined
·
583 Posts
Of course there is one in the full size spare. If not, the TPMS would go crazy. Also, it can set off the TPMS on the dash. If all of your tires are filled and you are getting the warning. Make sure your spare is filled as well.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #7 ·
The reason I ask is the dash only appears to show tire pressures for the four wheels on the 2013 evic display.
 

·
Registered
Joined
·
583 Posts
The reason I ask is the dash only appears to show tire pressures for the four wheels on the 2013 evic display.
Why would it show the spare!? :rofl: The system shows the tire pressure for your safety while driving on those 4 tires. If one of those tires fails, you move the spare to that spot and the system will pick display it.
 

·
Registered
Joined
·
214 Posts
My 13 sport desn't have the TPMS option but the sensors are there so I'm pretty sure all 17" wheels have the sensors installed
 

·
Premium Member
Joined
·
1,996 Posts
I don't have full access to pull the requirement but a few years back it becam a federal requirement that all us vehicles must now be equipped with TPMS monitoring. So everyone should have it.

And it does monitor the spare at all times. You can search the threads and many people have had TPMs lights on and after hours of trouble shooting with no luck have finally found that it was the spare tire that was low. The TPMS only monitors a sensor freq. it does not know which tire is low or how many tires there actually are.
 

·
Registered
Joined
·
1,251 Posts
I don't have full access to pull the requirement but a few years back it becam a federal requirement that all us vehicles must now be equipped with TPMS monitoring. So everyone should have it.

And it does monitor the spare at all times. You can search the threads and many people have had TPMs lights on and after hours of trouble shooting with no luck have finally found that it was the spare tire that was low. The TPMS only monitors a sensor freq. it does not know which tire is low or how many tires there actually are.
While the is a TPMS sensor in the spare the system doesn't monitor the spare. Sensors are activated by inertial control and the spare doesn't spin. The system sees 4 uniqiue id'd active sensors reporting a pressure.
Let the air out of your spare and see what (doesn't) happen.

Most of those people that reported dash lights simply inflated past the threshold turning them off. A cheap tire gauge that reports on the high side will cause this problem.
 

·
Registered
Joined
·
125 Posts
Sorry for bumping an old thread but I was curious about this as well. I just sold my original set of tires off a 2013 JKU last night, and while I had transferred the sensors to my 4 new wheels and tires when I had them changed (I only bought 4 new wheels and tires and kept one of the originals for a spare), I totally forgot about the one that was still in the original spare.

So I sold my spare along with the original set of 4 last night but no lights have lit up on the dash yet.

So I am assuming this must be true, as long as the wheel is not in motion then it is not being monitored by the computer, unless my dash light is suddenly going to come on today.
 

·
Registered
Joined
·
1,251 Posts
Sorry for bumping an old thread but I was curious about this as well. I just sold my original set of tires off a 2013 JKU last night, and while I had transferred the sensors to my 4 new wheels and tires when I had them changed (I only bought 4 new wheels and tires and kept one of the originals for a spare), I totally forgot about the one that was still in the original spare.

So I sold my spare along with the original set of 4 last night but no lights have lit up on the dash yet.

So I am assuming this must be true, as long as the wheel is not in motion then it is not being monitored by the computer, unless my dash light is suddenly going to come on today.
No worry, your light won't come on because of the spare. Get a sharpie and write "No TPMS - 01/17/13" on the inside of the spare's rim, so a few years from now when you use it you'll know why the dash light comes on.

There's a guy on ebay selling 2013 TPMS sensors, for $44/set. I've bought and installed a few sets
4 New Chrysler Dodge Jeep TPMS 56029398AB 433MHz Tire Pressure Sensors | eBay
 

·
Registered
Joined
·
186 Posts
^ What JKs1H1 said. I have been rolling without my spare mounted for a few weeks now, while I wait for my tire carrier bumper. I have yet to set off a TPMS error. But on my wife's Range Rover, if the spare, which is mounted under the back of the vehicle, is low, it will set off the TPMS sensor. So I guess it depends on the vehicle....
 

·
Banned
Joined
·
289 Posts
Should be in all five or you'd have problems with the TPMS when you do a five tire rotation. I know the 2012s have them in all five.
The Spare isn't part of a Tire Rotation, for one, that's why it's called a spare, to be ready when needed, not worn out/down. Per the owners manual, it shows you how to rotate and the spare will not set off the tire warnings.... A spare is to be used as a spare, not as a permanent solution.

from manual:

A tire pressure monitoring sensor is located in the spare
wheel if the vehicle is equipped with a matching full size
spare wheel and tire assembly. The matching full size
spare tire can be used in place of any of the four road
tires. A low spare tire will not cause the “Tire Pressure
Monitoring Telltale Light” to illuminate or the chime to
sound.
The Tire Pressure Monitor System (TPMS) consists of the
following components:
• Receiver Module
• Four Tire Pressure Monitoring Sensors
• Tire Pressure Monitoring Telltale Light...

TIRE ROTATION RECOMMENDATIONS
The tires on the front and rear of your vehicle operate at
different loads and perform different steering, handling,
and braking functions. For these reasons, they wear at
unequal rates.
These effects can be reduced by timely rotation of tires.
The benefits of rotation are especially worthwhile with
aggressive tread designs such as those on On/Off Road
type tires. Rotation will increase tread life, help to maintain
mud, snow, and wet traction levels, and contribute to
a smooth, quiet ride.
Refer to the “Maintenance Schedule” for the proper maintenance
intervals. The reasons for any rapid or unusual
wear should be corrected prior to rotation being performed.
The suggested rotation method is the “forward-cross”
shown in the following diagram.

Text Line Font Parallel Diagram
 

·
Banned
Joined
·
289 Posts
While the is a TPMS sensor in the spare the system doesn't monitor the spare. Sensors are activated by inertial control and the spare doesn't spin. The system sees 4 uniqiue id'd active sensors reporting a pressure.
Let the air out of your spare and see what (doesn't) happen.

Most of those people that reported dash lights simply inflated past the threshold turning them off. A cheap tire gauge that reports on the high side will cause this problem.
You are Right....Here is that info from the 2013 Owners manual:

A tire pressure monitoring sensor is located in the spare
wheel if the vehicle is equipped with a matching full size
spare wheel and tire assembly. The matching full size
spare tire can be used in place of any of the four road
tires. A low spare tire will not cause the “Tire Pressure
Monitoring Telltale Light” to illuminate or the chime to
sound.
 

·
Banned
Joined
·
289 Posts
I don't have full access to pull the requirement but a few years back it becam a federal requirement that all us vehicles must now be equipped with TPMS monitoring. So everyone should have it.

And it does monitor the spare at all times. You can search the threads and many people have had TPMs lights on and after hours of trouble shooting with no luck have finally found that it was the spare tire that was low. The TPMS only monitors a sensor freq. it does not know which tire is low or how many tires there actually are.
REad your Manual.....plus thst's the only way these devices can work.....if they were on 24/7 they would have to be changed very often....the Battery can't be that big and last that long....so how else could that work?
 

·
Banned
Joined
·
289 Posts
How a Tire Pressure Monitoring System Works

As its name suggests, a tire pressure monitoring system is more than a single part. In fact, TPMS involves a valve and a sensor, and it's also important to know that not all TPMS systems are created equal.There are two kinds of TPMS technology–indirect and direct. Indirect TPMS approximates tire pressure indirectly by using data from the vehicle's antilock brake system (ABS). Direct TPMS provides a more accurate calculation of your tire pressure using data gathered directly from a sensor placed inside each tire.
In either case, if a tire is detected to be underinflated by 25% or more, an alert lights up on your dashboard. But with direct TPMS, drivers are alerted sooner and–if the car is equipped with the four-tire TPMS display–can even see readings for each tire. One of the largest downsides of an indirect TPMS system is that it cannot detect when all four tires are low in pressure, which can happen quite frequently if tire pressure is not checked on a regular basis.
To get a better understanding of how TPMS works and how it helps make driving safer, watch this video on TPMS technology.
 

·
Banned
Joined
·
289 Posts
DIRECT & INDIRECT TIRE PRESSURE MONITORS
There are essentially two basic ways to monitor tire pressure electronically. One is the direct method. A small pressure sensor is located inside each wheel. The sensor has a built-in transponder that broadcasts a radio signal to an external module. The module identifies the signal from each wheel and keeps an eye on pressure. If pressure drops below a predetermined threshold, the module turns on a light or displays a message to warn the driver.


he pressure sensors may be mounted in the drop center inside the wheel, or on the end of the valve stem inside the wheel. Stem mounted pressure sensors use the valve stem as the antenna, so don't replace the standard valve caps with anything else. Sensors attached to the rim drop center are typically held in place by a long steel strap that wraps all the way around the wheel. The pressure sensors are very accurate (usually within 2 lbs. or less).

The other method of monitoring tire pressure does not require any additional hardware inside or outside the wheel. It is the "indirect" method. This approach makes use of the existing wheel speed sensors in the antilock brake (ABS) system. By modifying the ABS operating software, the ABS system learns the average speed at which each wheel rotates when traveling straight at a constant velocity, and detects low tires by comparing relative wheel speeds. The auto makers like this approach because it is a simple, cost-effective way to monitor tire pressure. But it has some limitations.

On most North American indirect TPMS systems (1999 to 2003 model year applications), the systems cannot detect a low tire if two tires on the same axle are low, or if all four tires are low by an equal amount. But it can detect one or more low tire if the rest are at or near the recommended inflation pressure. Some of the newest European indirect TPMS systems can detect air loss in any combination of tires, as well as a gradual loss of air pressure during cold weather in all four tires.

Here's how the indirect ABS-based TPMS works. If a tire loses air, the diameter of the tire shrinks slightly causing it to turn at a slightly faster rate than the others. But on most applications, a tire has to loose anywhere from 8 to 14 pounds of air pressure before there's enough of a difference in diameter to be detected by the wheel speed sensors. It depends on the type of tires, tire diameter and aspect ratio, and the sensitivity of the ABS system.

Low profile tires with short stiff sidewalls change diameter less than tires with taller aspect ratios and more compliant sidewalls. Consequently, a loss of 10 psi in a low profile tire may only change the diameter of the tire less than 1 mm (0.040 inches). Most ABS systems cannot detect changes smaller than 1 mm. For this reason, indirect ABS-based tire pressure monitoring systems are not as sensitive as direct TPMS systems that have a pressure sensor inside each wheel
 

·
Registered
Joined
·
1,251 Posts
The Spare isn't part of a Tire Rotation, for one, that's why it's called a spare, to be ready when needed, not worn out/down. Per the owners manual, it shows you how to rotate and the spare will not set off the tire warnings.... A spare is to be used as a spare, not as a permanent solution.
A spare on every JKU I have seen is the exact same wheel, tire, and TPMS sensor that's on every corner of your wrangler. As such, it's somewhat of a waste not to rotate it into the mix. (Rubber doesn't last forever). Not to be nit-picky, but if it's rotated in, it tends to be around the same outside diameter when they wear down (so your not putting on a slightly larger spare if the other tires are worn - works the diff more -ok-pretty nit-picky, but accurate nonetheless). Also, a new spare almost says "take me", so I always toss a more worn tire on there.
 
1 - 20 of 76 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top