TPMS Light After Installing 35x12.50R17 Tires

[kirkturk]

Hello everyone,
I recently installed 35x12.50R17 tires on my stock 7.5-inch rims. After doing the chalk test, I’ve been running them at 32 PSI. The issue is that my low tire pressure light has been on for over two months. I’ve read on different forums that dealers can reprogram the TPMS to recognize a new PSI, but after taking my Jeep in twice, I was told they cannot recalibrate or reprogram the warning system. Is that really the case? Does this mean every Jeep running different tire pressures has to live with the low tire light on the dash?
Is there a way to adjust this myself? I’ve seen devices that connect under the dash to reprogram tire sizes and settings, but I’m hesitant to trust them. Any suggestions or proven fixes would be appreciated. And yes, I know the “black tape over the dash light” trick but I’d prefer a real solution.
2025 Gladiator Sport S
Thanks,
Kirkturk

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[whysoserious]

https://www.jeepgladiatorforum.com/forum/threads/tpms-pressure-parameters-question.101621/

 

[ShadowsPapa]

Hello everyone,
I recently installed 35x12.50R17 tires on my stock 7.5-inch rims. After doing the chalk test, I’ve been running them at 32 PSI. The issue is that my low tire pressure light has been on for over two months. I’ve read on different forums that dealers can reprogram the TPMS to recognize a new PSI, but after taking my Jeep in twice, I was told they cannot recalibrate or reprogram the warning system. Is that really the case? Does this mean every Jeep running different tire pressures has to live with the low tire light on the dash?
Is there a way to adjust this myself? I’ve seen devices that connect under the dash to reprogram tire sizes and settings, but I’m hesitant to trust them. Any suggestions or proven fixes would be appreciated. And yes, I know the “black tape over the dash light” trick but I’d prefer a real solution.
2025 Gladiator Sport S
Thanks,
Kirkturk

I changed mine with JSCAN. I put on larger tires, and ran 36 psi instead of the highway tires at 38. I changed the low threshold to 28 psi and got by great.

I see Joe has provided a link.

With JSCAN, you have to look for the correct number to change - but it can be done

 

[NortonJTSS]

I changed mine with the Tazer JL mini.. It does all kinds of cool stuff and you can adjust your tire size so the speedo is calibrated properly

 

[kirkturk]

Thank you all for the information. So, looks like I will be going with the Tazer mini. I just get nervous thinking I am going to screw something up with the factory electronics then jeep will be screwed up and cost me a bundle to fix my screw up. And then dealer with void my warranty.
Thanks again everyone
Kirkturk

 

[pcrawfordpt]

Thank you all for the information. So, looks like I will be going with the Tazer mini. I just get nervous thinking I am going to screw something up with the factory electronics then jeep will be screwed up and cost me a bundle to fix my screw up. And then dealer with void my warranty.
Thanks again everyone
Kirkturk

The Tazer Mini is a valuable tool and a solid purchase. You do need to follow the direction carefully. Sleep cycles are very important. Most dealerships are cool with them, but some aren’t. They know most built Jeeps must have a Tazer or JScan to operate properly. Just work with them, and let them know it has been unmarried and removed for updates. If no update required, no reason to unmarry and removed. Tazers must be unmarried and removed when any factory computer updates are done. If not and the Tazer is removed later, that factory update will be removed as well..not good. Get the extension cable to make install and removal easier. Do the firmware updates whenever you remove it. Videos are very helpful as well.

 

[salvino]

Thank you all for the information. So, looks like I will be going with the Tazer mini. I just get nervous thinking I am going to screw something up with the factory electronics then jeep will be screwed up and cost me a bundle to fix my screw up. And then dealer with void my warranty.
Thanks again everyone
Kirkturk

Most Jeep dealers are very accustomed to seeing Tazers. None have ever complained about mine. The Tazer mini has many great features. You should definitely correct your tire size, the shifting will be much improved.

 

[ShadowsPapa]

The thing about tire sizes is - don't plug in 35 for a 35" tire.

And use the odometer to check that it's correct in the end. The speedometer can be deceiving. You can get close using speedometer but it's not close enough for me.
I used the trip meter in the cluster and a GPS app i my phone, drove something like 17.2 miles and when I got done - the GPS said I'd gone 17.2 miles, the odo/trip thing said I'd gone 17.2.
The speedometer rounds up and down - the odometer doesn't

This is how the BCM views tire size and it's not about diameter, although both tazer and jscan do the math for you, but it's really about rolling or dynamic circumference - just a bit that jscan shows of the 2020 I had -

___________________
Transfer Case High Ratio (0-16.382): 1.000
Axle Ratio (0-65.534): 3.730
Transfer Case Low Range Reduction Ratio (0-65.534): 2.720
Dynamic Tire Circumference (All or Rear) (0-65534 mm): 2508.000 mm

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