Spare tire can throw off Tpms?

corneileous said:

Sooo, while using your spare, your TPMS is saying it needs service? That's odd.

Usually with vehicles that have TPMS, when you put your spare on, the TPMS receiver on the vehicle is still reading the transmitter in the flat tire and is telling the system that there is a low tire because your spare doesn't have a transmitter in it.

How do you know it's telling you it needs service, tho? On mine, which is much older, a 2008, when the light comes on solid with a chime, it's telling me there is a low tire detected. When the light comes on and blinks about 10 ten times with a chime, it indicates a fault with the system.

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TRCM said:

Never heard of that crap....sounds more to me like they are trying to sell you a tire you don't need.....the TPMS monitors pressure in the tire not weight.

Yes, the spare DOES have a TPMS in it if you have a full size spare.

Straight from my owners manual:

The matching full size spare wheel and tire assembly (if equipped) has a TPM sensor. The matching full size spare
can be used in place of any of the four road tires. The TPMS will only monitor the pressure in the full size spare
when it is used in place of a road tire. Otherwise, a spare with a pressure below the low-pressure limit will not
cause the TPM Telltale Light to illuminate or the chime to sound.

Vehicles With Full Size Spare
1. The matching full size spare wheel and tire assembly has a TPM sensor that can be monitored by the TPMS.

2. If you install the full size spare in place of a road tire that has a pressure below the low-pressure warning limit,
upon the next ignition switch cycle, a chime will sound and the TPM Telltale Light will turn ON. In addition, the
EVIC will display a low pressure message and a graphic showing the low tire pressure value flashing.

3. After driving the vehicle for up to 20 minutes above 15 mph (24 km/h) the TPM Telltale Light will turn OFF,
as long as no tire pressure is below the low-pressure warning limit in any of the four active road tires.

The manual doesn't differentiate between 1500 & 2500, only full size spare versus compact spare.


For 2500's, there is a light load & a normal load, and you can switch between the 2, which changes the tire pressure the TPMS warns you at.

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mattstaub said:

Steel wheel for the spare?


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corneileous said:

So OP, what exactly is the problem you are having? Your Tire Pressure Monitoring System is saying there is a problem with the system when running your spare and the dealer is telling you it's because your spare doesn't weigh the same as your normal wheels??

I take it the pressure is what it should be in the spare?

Also, since it's a 2015 we're takin about, I'm assuming you can see on your gauge cluster what your tire pressures are? What's your spare showing?

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The hippie said:

the tpms says its 70 psi but in actual it's 80 psi

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The hippie said:

Yeah the spare wheel is steel not chrome.

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corneileous said:

Hmm. Have you verified that with a gauge? It's odd that the TPMS is saying 10 psi less than actual pressure.

Have you also verified that your TPMS is just telling you that you have a low tire and not saying it is detecting a fault?

I would kinda think there's a process you have to go to to make your TPMS work right in the event you have to use your spare, that you're not doing, causing the light since your spare has a sensor in it.

See like with my old truck, I don't have a sensor in my spare so if I have a flat, my TPMS light is gonna come on and stay on until I get the other tire fixed or replaced.

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TRCM said:

huh ? Chrome & steel are basically the same metal, one is just shinier due to the plating they put on it....unless you have an aluminum rim that has chrome plastic on it like all the 20" rims are. At any rate, the weight doesn't matter. if it did, then Ram would not have given you a steel spare with aluminum rims.






There is no process....the truck computer will know right away which tire is a road tire, and which is not.

Read your owners manual....it takes ~ 20 min of driving above 15 mph for it to re-set itself. Until it does that, it will give you a low warning for the tire that is low (the one the spare replaced).

I know my 2012 model has a TPMS in the spare...can't say for 2008 models.

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TRCM said:

huh ? Chrome & steel are basically the same metal, one is just shinier due to the plating they put on it....unless you have an aluminum rim that has chrome plastic on it like all the 20" rims are. At any rate, the weight doesn't matter. if it did, then Ram would not have given you a steel spare with aluminum rims.

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There is no process....the truck computer will know right away which tire is a road tire, and which is not.

Read your owners manual....it takes ~ 20 min of driving above 15 mph for it to re-set itself. Until it does that, it will give you a low warning for the tire that is low (the one the spare replaced).

I know my 2012 model has a TPMS in the spare...can't say for 2008 models.

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corneileous said:

I'm just guessing but I think he means his spare is just a regular steel wheel and not the chrome-clad aluminum.




For a while there before you edited your post, I thought you were just talking to the OP about reading his manual since he's the one having the issue but when you mentioned a 2008 model, I now don't think you are.

I'm not having problems with my TPMS...[emoji846]

I've already stated that my 08 doesn't even have a tire pressure sensor in the spare.

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TRCM said:

I was/am talking to the OP....



But, I know you said your spare doesn't have TPMS, but so did many others who just found out there spare did have/does have TPMS.

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