: TPS Ques



rand49er
01-04-07, 03:35 PM
Just got another set of tire pressure sensors for my Mille Miglias, but started thinking about interference from the original four sensors on my OEM wheels. Three are sitting in the garage near the car PLUS my spare (in the trunk, of course) has a sensor in it.

Besides storing the three OEM wheels/tires in the basement (presumably to get them out of range), what do others do? What about the spare? Can they be "shielded?"

(This may be a complication I hadn't thought about. :hmm: )

AmesCTS-V
01-04-07, 03:52 PM
When you reprogram the new sensors they are the sensor for each wheel. Doesn't matter where the old ones are sitting.

nikon
01-04-07, 03:59 PM
yup, just think if you parked next to another V if they did like you say, you'd have problems...but since its already "coded" to the car, you should be fine...now the VW toureg did have that problem...sitting on the new car lot one would read the ones next to it tire sensors...I guess thats just one of the reasons they dont make it anymore.

rand49er
01-04-07, 04:02 PM
When you reprogram the new sensors they are the sensor for each wheel. Doesn't matter where the old ones are sitting.:duh: DOH! That's right! When I release air out of each one, that tells the display which one is which.

Can I go crawl into a hole now. :helpless: Mods ... lock this thread.

mlg
01-04-07, 09:14 PM
wrap them in aluminum foil to shield their signal from the car sensor.

50 4Ever
01-05-07, 01:19 PM
I thought after a while they stopped transmitting to conserve battery life and a sudden pressure change or rotation above a certain speed would start them transmitting again. I have a Corvette with TPS and 4 extra CTS-V stock wheels for the V with TPS and I have no problem with interference.

:thumbsup:

AmesCTS-V
01-05-07, 01:27 PM
I haven't looked at exactly how they work. But I think it's pretty clear they all have a unique id of some sort and they transmit that along with the pressure data so the car knows what id goes with what tire. It wouldn't matter if there was a box of 1000 TPS's sitting inside the car it's not going to read them, just the 4 it's supposed to.

lawfive
01-05-07, 02:31 PM
:duh: DOH! That's right! When I release air out of each one, that tells the display which one is which.

Can I go crawl into a hole now. :helpless: Mods ... lock this thread.

Don't feel bad dude, others on this forum have done the same thing more than once. Don't ask me how I know...

tedcmiller
01-08-07, 08:37 AM
Most of the responses to the original question are correct. The system responds only to TPSs for which it has been programmed. The only potential problem is that a nearby TPS that you don't want programmed, transmits its code while you are in programming mode. This can happen even though wheels with TPSs that are not moving transmit much less frequently (once every hour as opposed to once every 20 sec., or something like that), they do not stop transmitting completely. I have reprogrammed the TPM system on both mine and my wife's car numerous times (following tire rotations and changes) with the cars sitting beside each other and have had no problems. However, because of the potential problem I just described, I verify that the system responds only to the TPSs on the car. There are several ways to do this. The simplest and most efficient way is to check the pressure display when pumping the tires up again. The TPS will transmit at that time due to the pressure change. Ensure that the display responds to the correct tire in the correct position.

AmesCTS-V
01-08-07, 08:45 AM
Most of the responses to the original question are correct. The system responds only to TPSs for which it has been programmed. The only potential problem is that a nearby TPS that you don't want programmed, transmits its code while you are in programming mode. This can happen even though wheels with TPSs that are not moving transmit much less frequently (once every hour as opposed to once every 20 sec., or something like that), they do not stop transmitting completely. I have reprogrammed the TPM system on both mine and my wife's car numerous times (following tire rotations and changes) with the cars sitting beside each other and have had no problems. However, because of the potential problem I just described, I verify that the system responds only to the TPSs on the car. There are several ways to do this. The simplest and most efficient way is to check the pressure display when pumping the tires up again. The TPS will transmit at that time due to the pressure change. Ensure that the display responds to the correct tire in the correct position.
While I suppose this is possible it's really really really unlikely. It takes a pretty huge pressure change to get them to transmit and be programmed to be accepted by the car. The chances that a tire that is just sitting there is going to have a pressure change like that before the tire that you are actually letting air out of is almost impossibly low.

tedcmiller
01-08-07, 01:39 PM
While I suppose this is possible it's really really really unlikely. It takes a pretty huge pressure change to get them to transmit and be programmed to be accepted by the car. The chances that a tire that is just sitting there is going to have a pressure change like that before the tire that you are actually letting air out of is almost impossibly low.

I don't think you read what I wrote carefully enough. It doesn't require a pressure change to cause the TPS to transmit. The factory service manual indicates that the TPS will transmit approximately every hour regardless of rotational speed or pressure changes. This is why the chances of getting a transmission from another TPS while programming the TPM are not as small as you might think.

AmesCTS-V
01-08-07, 02:00 PM
That assumes that the TPS's always send the same signal. I assumed that there is a normal transmit and the rapid pressure change and/or the magnet method caused the TPS to send a different signal.

I've got 8 TPS's in my garage. Just for the heck of it I'll put the car in program mode and if you are right eventually it should pickup one of the sensors doing it's once per hour thing and use that transmit to program the first tire. I think you only have something like 5 mins to program so I'll might have to repeat it a few times.

rand49er
01-08-07, 03:01 PM
That assumes that the TPS's always send the same signal. I assumed that there is a normal transmit and the rapid pressure change and/or the magnet method caused the TPS to send a different signal.

I've got 8 TPS's in my garage. Just for the heck of it I'll put the car in program mode and if you are right eventually it should pickup one of the sensors doing it's once per hour thing and use that transmit to program the first tire. I think you only have something like 5 mins to program so I'll might have to repeat it a few times.Very interesting. Say, what is the frequency of transmission by a given TPS during normal driving? Every few minutes or so?

(This reminds me of one of those tanks physicists use that are filled with a liquid (glycol?) used to detect quarks emitted by the sun; these are located way down underground in mines. :D )

Staxxin
01-08-07, 09:24 PM
That assumes that the TPS's always send the same signal. I assumed that there is a normal transmit and the rapid pressure change and/or the magnet method caused the TPS to send a different signal.

I've got 8 TPS's in my garage. Just for the heck of it I'll put the car in program mode and if you are right eventually it should pickup one of the sensors doing it's once per hour thing and use that transmit to program the first tire. I think you only have something like 5 mins to program so I'll might have to repeat it a few times.

Sorry to hijack... Ames- are you looking to sell any of them. I'm looking for 4 to put on my stock rims for Winter usage. If so, please send me a PM with the details.

Thanks,
John

AmesCTS-V
01-08-07, 09:29 PM
They are all on rims. Going from summer to winter rims without having to mess with TPS's is nice. GMPD has pretty good pricing on them which I got my dealership to match.

Staxxin
01-08-07, 09:41 PM
They are all on rims. Going from summer to winter rims without having to mess with TPS's is nice. GMPD has pretty good pricing on them which I got my dealership to match.

Thanks!! I'll check with James and see what they have.

ctsvett
01-08-07, 10:46 PM
To confirm the theory that they are still active despite sitting around:

A while back I bought a TPS from Dreamin and put it in my glove box in case I ever needed it. He had had it programmed on his car. I had no issues... He comes down to socal for a meet a year ago and parks his car next to mine. When we fire up to leave, he rolls down his window and asks me if I have the TPS in my car. I saw yes. He smiles and said he thought so.

The old TPS he had sold me a year prior was technically still attached to his car and read on his system when he fired the car and gave him a warning. Dreamin, can you confirm that you had TPSs on the car period?

Since you have Tires nearby but have reprogrammed new sensors, the "old" ones MAY interfere since they have not been reprogrammed... This is unlikely, but possible.

Reed

tedcmiller
01-09-07, 09:12 AM
The post by ctsvett illustrates the problem to which I am referring.

I've got 8 TPS's in my garage. Just for the heck of it I'll put the car in program mode and if you are right eventually it should pickup one of the sensors doing it's once per hour thing and use that transmit to program the first tire. I think you only have something like 5 mins to program so I'll might have to repeat it a few times.

Sorry, AMEScts-v your proposed experiment is not sufficient to prove me wrong. As you pointed out, the car will remain in programming mode a limited amount of time and repeatedly putting it into programming mode without receiving a transmission from one of your "extra" TPSs only proves that it didn't happen on that particular programming session. It does not prove that it can never happen. Obviously, based on ctsvett's post, it can.

Here are a few other facts: You can't use magnets on the CTS-V TPM. The service manual says so. Only a pressure change will force a transmission for programming. You can't use pressure change on a non-CTS-V TPM (e.g., Cadillac DTS) - only the magnets work in this case. I know because I tried it to avoid using magnets. Fortunately, a pack of five inexpensive ring magnets from Radio Shack works nicely.


I assumed that there is a normal transmit and the rapid pressure change and/or the magnet method caused the TPS to send a different signal.

This is an invalid assumption. There is no difference in TPS transmissions. It is always the same regardless of whether is caused by a pressure change, rotation, or timeout (once every 20 seconds when rotating or once every hour when not rotating).