Help! Tire Pressure readings for the wrong tires!

[Kennadian]

I imagine somewhere on the cpu unit there is a place where 4 connections are made for the tire pressure sensors. On my 05 XLR the left front tire is actually reading the right rear tire pressure. I discovered this when I got a low pressure warning and filled the indicated tire only to find that it changed a different tire's reading!!! Wha......

Does anybody know where these connections are made so I can investigage and get it corrected?

 

[xlrlist01]

I imagine somewhere on the cpu unit there is a place where 4 connections are made for the tire pressure sensors. On my 05 XLR the left front tire is actually reading the right rear tire pressure. I discovered this when I got a low pressure warning and filled the indicated tire only to find that it changed a different tire's reading!!! Wha......

Does anybody know where these connections are made so I can investigage and get it corrected?

There is a process (below) that allows you to reset this. It involves a special tool that is basically a power magnet that you take round each wheel in turn. You have to get the system into the correct mode and then go round each tire stem in order and before a time out (15 seconds per wheel, 1 minute in all).

Here it is:
1/ Go into acc mode with the ignition switch.
2/ Press and hold together the lock and unlock buttons on the key fob remote. This will result in a double horn chirp, confirming that you are in program mode.
3/ Using the special tool (or a very powerful magnet), go to Left Front and place the tool on/over the valve stem (at the bottom of the stem, on the wheel). A chirp from the horn tells you it has registered.
4/ Visit the wheels in the order (LF), Right Front, Right Rear, Left Rear. You should get a chirp each time.
5/ Completing the LR should result in a double chirp. The sensors have been learned.

HTHs

 

[Kennadian]

There is a process (below) that allows you to reset this. It involves a special tool that is basically a power magnet that you take round each wheel in turn. You have to get the system into the correct mode and then go round each tire stem in order and before a time out (15 seconds per wheel, 1 minute in all).

Here it is:
1/ Go into acc mode with the ignition switch.
2/ Press and hold together the lock and unlock buttons on the key fob remote. This will result in a double horn chirp, confirming that you are in program mode.
3/ Using the special tool (or a very powerful magnet), go to Left Front and place the tool on/over the valve stem (at the bottom of the stem, on the wheel). A chirp from the horn tells you it has registered.
4/ Visit the wheels in the order (LF), Right Front, Right Rear, Left Rear. You should get a chirp each time.
5/ Completing the LR should result in a double chirp. The sensors have been learned.

HTHs

Thanks so much for this information. I'll try to find a BIG magnet and give it a try. Stay tuned!

 

[mtrocket]

Thanks so much for this information. I'll try to find a BIG magnet and give it a try. Stay tuned!

Or just go to a tire shop... shouldn't be THAT expensive to just have the sensors programmed.

 

[Crimson Pearl]

This is a procedure that has to be performed any time you rotate tires. My Tahoe has a TPMS like that on the XLR and my tire dealer performs the "re-learn" procedure each time tires are rotated.

 

[05 GRAND DADDY]

I did not ever notice that! I guess an easy check would be add air to a tire a see which one it shows up on, but they filled mine with nitrogen!


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Dan & Wendy
" 05 GRAND DADDY"

 

[mtrocket]

I did not ever notice that! I guess an easy check would be add air to a tire a see which one it shows up on, but they filled mine with nitrogen!


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Dan & Wendy
" 05 GRAND DADDY"

When I purchased my tires at Costco, they were filled with Nitrogen. I asked about topping them off with regular air, if necessary, and was told, "No problem."

 

[cubby558]

I always thought this was a scam to get more money out of you. The air we breathe is 78% nitrogen!!

........................................................................................filled mine with nitrogen!


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Dan & Wendy
" 05 GRAND DADDY"

 

[V Happy]

-Tire-Pressure-readings-for-the-wrong-tires!

This may help the conversation.
V Happy
[h=1]Is Nitrogen Better than Air in Car Tires?[/h]

By Mike Allen


Comments 112


Share







February 1, 2009 12:00 AM

Q: Is there any advantage to using nitrogen instead of compressed air in tires? Will I notice improved fuel economy or a smoother ride? Will my tires last longer?

A: Sort of. From the top: Air is 78 percent nitrogen, just under 21 percent oxygen, and the rest is water vapor, CO2 and small concentrations of noble gases such as neon and argon. We can ignore the other gases.

There are several compelling reasons to use pure nitrogen in tires.

First is that nitrogen is less likely to migrate through tire rubber than is oxygen, which means that your tire pressures will remain more stable over the long term. Racers figured out pretty quickly that tires filled with nitrogen rather than air also exhibit less pressure change with temperature swings. That means more consistent inflation pressures during a race as the tires heat up. And when you're tweaking a race car's handling with half-psi changes, that's important.

Passenger cars can also benefit from the more stable pressures. But there's more: Humidity (water) is a Bad Thing to have inside a tire. Water, present as a vapor or even as a liquid in a tire, causes more of a pressure change with temperature swings than dry air does. It also promotes corrosion of the steel or aluminum rim.

If I ever need to top off a tire when I'm out on the road, I'll always briefly depress the tire chuck's valve with my thumbnail and vent some air. If my thumb gets wet, there's water in the line. Some gas stations don't do a very good job of keeping the humidity out of their air system. I don't even like to use a water-based tire-mounting lubricant unless I can let the tire bake in the sun for a couple of hours before I air it up and seat the bead. I've dismounted tires (not mine) that had several quarts of water inside—probably from a compressed-air hose that collected water and was never purged properly.

How is water relevant to a nitrogen discussion? Any system that delivers pure nitrogen is also going to deliver dry nitrogen. Filling tires with nitrogen involves filling and purging several times in succession, serially diluting the concentration of oxygen in the tire. This will also remove any water.

It's certainly simple, although time-consuming, for a tire technician to fill and bleed tires. But most shops use a machine that not only generates almost pure nitrogen by straining the oxygen out of shop-compressed air, but will also automatically go through several purge cycles unattended. Some shops have been charging as much as $30 per tire for this service. I think that's too much. If you're buying a new tire, it should be far less. Still, the nitrogen generator, filling system and technician's time aren't free—the dealer is entitled to some return for that.

So, to answer your specific questions: With nitrogen, your tire pressures will remain more constant, saving you a small amount in fuel and tire-maintenance costs. There will be less moisture inside your tires, meaning less corrosion on your wheels. You will not be able to feel any difference in the ride or handling or braking, unless your tire pressures were seriously out of spec and changing to nitrogen brought them back to the proper numbers.



Read more: Nitrogen vs Air In Tires - Why Nitrogen in Tires - Popular Mechanics
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Visit us at PopularMechanics.com

 

[xlrlist01]

For me, using very dry air (using special dryers) from the airline works nearly as well as Nitrogen is said to work.

 

[05 GRAND DADDY]

Well I can't argue about the deal when it was free with install and free top off check when they rotate my tires for free!


Sent from my iPhone using Tapatalk
Dan & Wendy
" 05 GRAND DADDY"

 

[Kennadian]

There is a process (below) that allows you to reset this. It involves a special tool that is basically a power magnet that you take round each wheel in turn. You have to get the system into the correct mode and then go round each tire stem in order and before a time out (15 seconds per wheel, 1 minute in all).

Here it is:
1/ Go into acc mode with the ignition switch.
2/ Press and hold together the lock and unlock buttons on the key fob remote. This will result in a double horn chirp, confirming that you are in program mode.
3/ Using the special tool (or a very powerful magnet), go to Left Front and place the tool on/over the valve stem (at the bottom of the stem, on the wheel). A chirp from the horn tells you it has registered.
4/ Visit the wheels in the order (LF), Right Front, Right Rear, Left Rear. You should get a chirp each time.
5/ Completing the LR should result in a double chirp. The sensors have been learned.

HTHs

I tried the procedure as indicated above. when I hold down the lock & unlock buttons simultaneously I only get one honk, not two....... There is no effect when I use my magnet on the rims....

Perhaps I'm not holding down the buttons long enough? I did give it about another 10 seconds after the first "chirp"

Thoughts?

 

[xlrlist01]

I tried the procedure as indicated above. when I hold down the lock & unlock buttons simultaneously I only get one honk, not two....... There is no effect when I use my magnet on the rims....

Perhaps I'm not holding down the buttons long enough? I did give it about another 10 seconds after the first "chirp"

Thoughts?

I'm quoting from page 3-97 of the 2004 workshop manual, 'Tire Pressure Sensor Learn'. I have followed the instructions myself and they work as stated. Not a lot of use to you I know, but information. BTW, I used a magnet taken out of a computer hard disk drive.

Have you driven your XLR a reasonable distance recently? It is necessary for the batteries in the tire pressure sensors to be charged up and they are charged by driving. Apart from that, there isn't anything else I know of. I assume you haven't got error messages on the DIC.

One thought - you are driving a domestic XLR? The process varies for some export models. Domestic and European is as stated. Japanese is different, you would need to read the workshop manual, it involves resetting the system and driving for 30 minutes at each of three different speeds. Middle East isn't mentioned.

Anyone else?

 

[SrChief]

Take it to a good tire shop (I use Discount Tire or Sam,s club) and get the tires rotated and they will calibrate them at the same time.

 

[ald42]

Well I can't argue about the deal when it was free with install and free top off check when they rotate my tires for free!


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Dan & Wendy
" 05 GRAND DADDY"

Dan, FREE is good