Jeep Commander Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
99 Posts
Discussion Starter #1
I have no TPMS signal from any tire mounted in my left rear position. After reading other threads on TPMS problems, this seems to be a common occurrence. I have moved all my tires around and they all read OK until I put them in the left rear position. No tire TPMS reads in that position even when I know the TPMS reads OK in any other position. I know other have similar issues and I would like to know if anyone successfully fixed it. I have read somewhere that the 06 XK used the 315 MHz frequency for the 06 model but later changed to a different frequency due to interference problems. I suspect my problems is one of the following:
1) The 315 frequency has interference problems in the left rear position. If true, I would like to know what other item nearby uses the frequency for a signal. I would like to disconnect the other item and see if that fixes my TPMS issue so I can confirm that this is a frequency interference issue.
2) Weak battery. As far as I know, the TPMS sensors are the factory originals and they could be near the end of their battery life. Although they work in other tire positions, a weak battery could cause the signal to be low enough that it cannot punch thru any interference to reach the receiver (at the key). I had my TPMS sensors tested by a local tire shop and they said they were all working except for the left rear and spare. I suspect all they did was look at the dash display and report what it was saying. At the time I had them tested, I had not yet moved tires around and discovered my problem was left rear related.
PS - my spare shows as low on dash display also but I have not played around with it but I suspect it might read OK is I put it on the ground in a good position.

Bottom line - if this is due to the sensors being near the end of their life, I am OK with replacing them but I don't want to go to the expense of replacing them unless I know that will fix the problem. If I cannot find the problem, I plan to replace one sensor and put that tire in left rear position and see if that fixes the problem. If it does, then I will replace all so I have a fresh start.

Anyone else have this problem? How did you fix it?
 

·
Premium Member
Joined
·
683 Posts
Your thought of weak batteries in your original wheels could be the problem - Life is about 10 years. The sensor for TPMS on the rear reads both rear wheels and the spare where the front ones have one for each. Possibly get one new and try it in the left rear. Sorry I do not remember where the rear sensor is to help.
Did you try a search here for "TPMS" ? a lot of discussions.
 

·
Registered
Joined
·
99 Posts
Discussion Starter #3
Your thought of weak batteries in your original wheels could be the problem - Life is about 10 years. The sensor for TPMS on the rear reads both rear wheels and the spare where the front ones have one for each. Possibly get one new and try it in the left rear. Sorry I do not remember where the rear sensor is to help.
Did you try a search here for "TPMS" ? a lot of discussions.
Actually, there are no rear or front "sensors" that read the tire TPMS sensors. Major misconception among owners. Those "sensors" you are referring to are actually "transponders". Their job is to tell a tire sensor when to transmit their signal. All sensors transmit signals periodically but the computer cannot tell which tire is sending. However, with the transponders, the computer can tell a specific tire (via transponder) independently for each front and right rear when to transmit a transmit a signal. The timing of the signal received by the computer then allows the computer to determine the placement of each sensor. The left rear has no transponder. However, since it is also sending a signal periodically (when moving), the computers can use the process of elimination to determine that the unidentified signal is from the left rear. The spare is also transmitting but at a less frequent schedule (not rotating thus a different schedule) . Based on these differences, the computer determines which tire is in each spot.
This is what allows us to move tires around in any manner and the computer figures it out after a short time of driving.
 

·
Premium Member
Joined
·
683 Posts
OK whatever you call it there is something picking up the signals from each wheel. My theory is the left rear is furthest from that device and a weak battery may cause it to not reach the pickup device. All 5 being weak they may all work everywhere but the left rear. Worth a shot as you say they are the originals and 11 years old. Try the spare if it doesn't transmit as often the battery may be better. Just my theory. I serviced computers (not PCs) for 40 years.
 

·
Registered
Joined
·
99 Posts
Discussion Starter #5
OK whatever you call it there is something picking up the signals from each wheel. My theory is the left rear is furthest from that device and a weak battery may cause it to not reach the pickup device. All 5 being weak they may all work everywhere but the left rear. Worth a shot as you say they are the originals and 11 years old. Try the spare if it doesn't transmit as often the battery may be better. Just my theory. I serviced computers (not PCs) for 40 years.
You are right. The signal pick-up point is at the key. Same receiver receives signals from your key fob to unlock doors as well as verifies a proper key when you insert your key to start the vehicle. Although the left rear is slightly closer physically to the key position than the right rear, I think the left rear position has the most metal mass in a straight line to interfere with a signal before it reaches the receiver at the key. That mass attenuates (weakens) the signal and I suspect a weak signal is unable to successfully penetrate that mass of metal. I too am a techie (50 years as an engineer).
Unless someone here has a better solution, I am going with the weak batter theory for now and will replace one TPMS tire sensor and see what happens.
 

·
Registered
Joined
·
99 Posts
Discussion Starter #6
I decided to try a new TPMS wheel sensor (MOPAR) in my left rear and see if that fixes my problem. I needed one new tire anyway so this was a good time to set up one new tire with a new MOPAR sensor and place it in the left rear. If this works, I plan to get new tires all around and I will add new sensors in each wheel at the same time so I will have new ones in all wheels.
 

·
Registered
Joined
·
1 Posts
No updates on this thread in a few years I see. Still own my Jeep Commander and no problems except this issue. Still feels and drives like a new car except the issue in this thread. Some minor repairs over time (alternator, battery, starter, leak repair and computer update flashes). I have had this same Left Rear TPMS signal issue since I first bought the vehicle in 2008. I had the Left Rear TPMS Tire Sensor replaced once under warranty and once since warranty expiration and the issue remains. I would love to know if anyone had a resolve on this issue. After the age of the vehicle I do not plan to invest in diagnostics at a Stealership as most of the work I have done myself with the exception of computer flash updates and TPMS Left Rear Tire Sensor (of coarse oil, filter, brake, Plugs, Bulbs, Services, Oil changes for those that want to dissect every word. I believe in maintenance on any vehicle) . Can anyone direct me to the location of the transponder or receiver unit of the signal from the Left Rear Tire Sensor? I believe that must be the issue based on previous comments and experience. Perhaps location or interference to the receiver is the problem. Could well be a design flaw. Perhaps I can redesign. Very annoying sometimes. Thanks for any input.
 

·
Premium Member
Joined
·
683 Posts

·
Premium Member
Joined
·
683 Posts
Researched a little further. Read this from the service manual. Note - for the TPMS that displays pressures of each tire.

DESCRIPTION - PREMIUM SYSTEM

A transponder is located in three of the four wheel wells of the vehicle to provide the WCM/SKREEM with the location of the tire pressure sensors on the vehicle. The transponders are located in the left front, right front and right rear wheel wells. A fourth transponder is not necessary in the remaining wheel well due to the process-of-elimination theory. Once the system knows the location of the first three sensors it assumes the location of the fourth tire pressure sensor is in the left rear tire.

Also read there are things the dealer can program for the TPMS.
Also try a reset - remove the battery + cable for 5 minutes and reconnect to reset everything.
I assume you moved the tires/wheels around and it stayed Left rear location bad? - Not by wheel.
 
1 - 9 of 9 Posts
Top