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Setting TPMS Thresholds

C.Sco

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Mine does the same thing except it gives me the warning at < 25 PSI to inflate to 15psi. I haven't really spent any time poking around in Jscan to try to resolve it yet though.
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THAW

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I had set mine - using jscan - to 20psi and the warning seemed to work as expected. The warning light came on when my tire pressure was around 19psi or lower.
Federal law for pressure warning specifies -25% of the recommended pressure. So, a 20 PSI setting would imply a warning at ~15 PSI, whereas a 19 PSI warning would imply a ~25 PSI setting.

Given your results, it seems the Tazer instruction regarding a 25 PSI JL-minimum-allowed-setting is perhaps accurate, even though JScan appears to set it lower. And, based on 2 reports in this thread that the warning's "inflate to" number populates with the threshold setting data though the TPMS live data is already higher suggests there may be issues with the JScan implementation (or that it somehow works differently than expected).
 
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LAM

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Federal law for pressure warning specifies -25% of the recommended pressure. So, a 20 PSI setting would imply a warning at ~15 PSI, whereas a 19 PSI warning would imply a ~25 PSI setting.

Given your results, it seems the Tazer instruction regarding a 25 PSI JL-minimum-allowed-setting is perhaps accurate, even though JScan appears to set it lower. And, based on 2 reports in this thread that the warning's "inflate to" number populates with the threshold setting data (though the live TPMS live data is already higher) suggests there may be issues with the JScan implementation (or that it works differently than expected).
So it was the lawyers…... or politicians. Same thing.
 
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Terrymo

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Federal law for pressure warning specifies -25% of the recommended pressure. So, a 20 PSI setting would imply a warning at ~15 PSI, whereas a 19 PSI warning would imply a ~25 PSI setting.

Given your results, it seems the Tazer instruction regarding a 25 PSI JL-minimum-allowed-setting is perhaps accurate, even though JScan appears to set it lower. And, based on 2 reports in this thread that the warning's "inflate to" number populates with the threshold setting data though the TPMS live data is already higher suggests there may be issues with the JScan implementation (or that it somehow works differently than expected).
I messaged JSCAN and wrote this

Question regarding setting the lower TPMS threshold on a Jeep JL Wrangler. Tazer documentation says “The Jeeps computer will only recognize a minimum pressure of 25 psi. JSCAN documentation simply says “change this to your liking.” I have read the JL wrangler is “hard coded” to prevent the TPMS threshold from being set below 25 psi without triggering warning lights or messages. What is the minimum TPMS threshold the Jeep JL can be set to using JSCAN without having warning lights or messages. Thank you.

Their reply

Might be 25 indeed
 

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I have mine set to 24 via JSCAN, havent seen any warning light for about 700 miles
 

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Terrymo

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I have mine set to 24 via JSCAN, havent seen any warning light for about 700 miles
With your threshold set to 24 via JSCAN at what actual tire pressure does the warning light or message come on?
 
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@THAW’s explanation makes a lot of sense. The 25 number appears to be coded into the Jeep software regardless of where the threshold is set, hence the weird message on the dashboard.

Now if Jscan could access that number and change it that would be nice. Otherwise I gotta follow federal law. Hope I don’t get another flat.
 

Terrymo

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@THAW’s explanation makes a lot of sense. The 25 number appears to be coded into the Jeep software regardless of where the threshold is set, hence the weird message on the dashboard.

Now if Jscan could access that number and change it that would be nice. Otherwise I gotta follow federal law. Hope I don’t get another flat.
I was laughing at JSCANs reply to my question. Very technical and informative.
 

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With your threshold set to 24 via JSCAN at what actual tire pressure does the warning light or message come on?
I havent air down yet to trigger that warning light. With my Jeep in pieces, it will be a while before I can test it out
 

THAW

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I messaged JSCAN and wrote this

Question regarding setting the lower TPMS threshold on a Jeep JL Wrangler. Tazer documentation says “The Jeeps computer will only recognize a minimum pressure of 25 psi. JSCAN documentation simply says “change this to your liking.” I have read the JL wrangler is “hard coded” to prevent the TPMS threshold from being set below 25 psi without triggering warning lights or messages. What is the minimum TPMS threshold the Jeep JL can be set to using JSCAN without having warning lights or messages. Thank you.

Their reply

Might be 25 indeed
Jeep Wrangler JL Setting TPMS Thresholds 1000004789
 

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