JScan & TPMS ... am I doing something wrong?

[mrtm1970]

Ok, so I changed the min PSI setting for both the front & rear tires to 25 PSI and Max to 40 PSI...when I start up the JLUR now I get PSI too low air up to 40 PSI and my tires are at 32/33 PSI.

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[Dailydrivenwrangler]

Yes you did.

With JScan things are weird. You need to set the max pressure on JScan to what you want your low pressure to be. So set the high pressure to 25 and leave the low blank and it will be fine.

 

[mrtm1970]

Yes you did.

With JScan things are weird. You need to set the max pressure on JScan to what you want your low pressure to be. So set the high pressure to 25 and leave the low blank and it will be fine.

Thank you!

 

[Htfan]

Yes you did.

With JScan things are weird. You need to set the max pressure on JScan to what you want your low pressure to be. So set the high pressure to 25 and leave the low blank and it will be fine.

So glad I noticed this thread! I'm getting ready to make a PSI change.

I'm sharing this quote from the JScan document site:

https://jscan-docs.readthedocs.io/en/latest/general/tpms.html

"Changing TPMS thresholds

Connect to your vehicle

Open Adaptation

Open TPMS settings

Set TPMS thresholds in the applicable setting(s) from the following list:

TPMS Threshold: for vehicles equipped with the basic version
TPMS Threshold - EVIC version: well… yes, for vehicles with the premium version
Light Load Inflation Pressure Front / Rear Tire: Leave at 0.
Max Load Inflation Pressure Front / Rear Tire: This value is used as the minimum pressure when the vehicle is fully loaded. Change this value first and see if it does the job.

Reset the TPMS:

Close the car, let it sit for a few minutes. If you see no change in behaviour, continue to the next step:
On most vehicles disconnecting the battery for a few minutes resets the TPMS, however:
some newer vehicles have others systems relying on a constant power supply, so instead you can use !Restart all ecus option (usually available in Miscellaneous Settings section)."

 

[Yawnie'sPapa]

Yeah, never mess with the minimum.
By law, TPMS triggers at 25% so if the door sticker says your tires should be 38 psi (like a stock Overland Gladiator), the TPMS will trigger at 28.5 pounds and go red when a tire gets down that low.
My new tires are, according to General, supposed to run 36 psi for my tire size and the weight of my JT, so I looked for the line that said 38 and changed it - jscan only allows increments of 5 so I set it to 35 psi (close enough)
Now it will trigger at about 26 psi.
To prevent problems in the winter, I do air them back up when the temps drop in late fall - like the tire companies recommend. Yes, in the winter I air them back up to about 35-36 psi, then in the spring I air them to what they should be again, usually meaning I let a bit out.

So the low is automatic - the system figures what ever the psi is supposed to be, it will allow it to drop as low as 75% (or a loss of 25%) before tripping and alerting.

 

[mrtm1970]

Ok…well maybe I need to disconnect the battery or wait to see if it does the same when I leave work today.

This is what I got after adjusting min to 0 and Max to 25psi:

 

[mrtm1970]

Ok…well maybe I need to disconnect the battery or wait to see if it does the same when I leave work today.

This is what I got after adjusting min to 0 and Max to 25psi:

Ok it works now but new/old issue..

@Rhinebeck01

In the pic above the rear right tire monitor shows not reading…I just rotated the tires when I put the lift on and that same right rear was not reading even before then. So is possibly a part of the the other side of the TPMS at that tire that could cause this problem? What would need to be fixed/replaced if this is the case?

 

[Rhinebeck01]

Ok it works now but new/old issue..

@Rhinebeck01

In the pic above the rear right tire monitor shows not reading…I just rotated the tires when I put the lift on and that same right rear was not reading even before then. So is possibly a part of the the other side of the TPMS at that tire that could cause this problem? What would need to be fixed/replaced if this is the case?

You should have addressed this before you brought JSCAN
into the mix ..

Try this as often the spare tire messes things up.... remove the spare, leave it in the garage and with the PSI's all set as per the door placard, go drive for a few minutes. Once all displays properly, put the spare back on the spare holder.

 

[mrtm1970]

You should have addressed this before you brought JSCAN
into the mix ..

Try this as often the spare tire messes things up.... remove the spare, leave it in the garage and with the PSI's all set as per the door placard, go drive for a few minutes. Once all displays properly, put the spare back on the spare holder.

@Rhinebeck01

worked … somewhat…switched to the other side:

 

[Rhinebeck01]

@Rhinebeck01

worked … somewhat…switched to the other side:

@mrtm1970
@Goin2drt

Strange.... Try this ..... With spare off the JL, set all tires to placard psi and then do a 12 volt power kill. Wait say 10 min. and then restore 12v and go for another drive..

By the way, did you get your ECRI mount installed... did you find the screw?

 

[mrtm1970]

@mrtm1970
@Goin2drt

Strange.... Try this ..... With spare off the JL, set all tires to placard psi and then do a 12 volt power kill. Wait say 10 min. and then restore 12v and go for another drive..

By the way, did you get your ECRI mount installed... did you find the screw?

I am riding around with no spare…I am getting my kids and will try the battery kill probably this weekend or later today.

I will also look for that mounting point for the ECRI then too

 

[mrtm1970]

@Rhinebeck01

Disconnected positive battery for 10 min and did some errands for about an hour and no bueno.

 

[Rhinebeck01]

@Rhinebeck01

Disconnected positive battery for 10 min and did some errands for about an hour and no bueno.

You need to do a total 12v power kill if there is a chance that this would work.

 

[mrtm1970]

You need to do a total 12v power kill if there is a chance that this would work.

ok…I thought that was a 12V power kill…

SO I just read I have to disconnect the 2 negatives off the engine side and also the battery negative terminal for full 12V kill

 

[mrtm1970]

@Rhinebeck01

Did the proper 12V kill for 15 min and just got back from driving about 2 hrs on the highway and no bueno. Will be putting the spare back on for Easter drive tomorrow.

Might order that sensor part that is above the rear crossmember. Also might just disable the TPMS system in the mean time.

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