Can anybody tell me what the PSI threshold for the TPM is.
In other words, what pressure would trigger the alert?

Tires are stock for the KK Sport and pressure is at 33 PSI cold. The other day on the way home from work on the highway, I got the dashlight warning while exiting the highway. It blinked for a while and then went steady. When I got home I checked the pressure, after waiting a couple of hours, and all 4 were good at 33 PSI. When I started her up the next morning, no alert....and haven't seen it since then.

I can't find anything in the owners manual about what the trigger is.

Thanks,

Paul

_________________
2014 Cherokee Latitude, Deep Cherry Red 2.4L Tigershark for me.
2014 Cherokee Latitude, Billet Silver 3.2L for wifey.
2008 Patriot Sport, Jeep Green for son.

BASE TIRE PRESSURE MONITORING

The tire pressure monitoring system is designed to operate without loss of function for all OEM tire construction for this vehicle. The wheel sensor shall monitor tire pressure, air temperature inside the tire, wheel acceleration and the sensor internal battery status for all four active road tires. The sensor will broadcast this information, along with a unique 32 bit ID, to a central receiver circuit located inside the WCM. The information received by the WCM will be decoded and stored in memory (RAM) in the WCM. If a "warning or "fault" condition exists, the WCM will send a bus message request to illuminate the yellow telltale and to sound the chime.

If the WCM detects a warning or fault condition at ignition key "on" it will wait ten seconds +/- 10 % before sending the first request to illuminate the yellow telltale. This will assure that the display module has concluded its bulb check period. The display module will request a chime once per ignition cycle for each "warning" or "fault" condition detected. A "warning" or "fault" condition will remain enabled until the problem causing the condition is corrected and removed/reset.

The WCM shall continuously monitor for the receipt of tire pressure RF message transmissions from the wheel sensors during both the ignition key "on" and key "off" cycles. The wheel sensor ID's and the location of each sensor (e.g. Tire 1, Tire 2 etc.) are stored in the WCM non-volatile memory during the initial Manufacturing Plant Process, or during a service procedure, as required. The recommended "placard pressure", "low-pressure threshold" and “Hysteresis Pressure Values” for the tires installed on the vehicle, are stored in the WCM non-volatile memory during the initial Manufacturing Plant Process, or during a service procedure, as required. (Note: For vehicles with optional wheel/tire sizes and significantly different tire placard pressures, the placard pressure value and the low-pressure threshold value's programmable using a scan tool to accommodate the customer selected wheel/tire combinations recommended by DaimlerChrysler).

The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off the indicator lamp until the tire pressure is at or above the Low Pressure (lamp) OFF threshold (see placard table below). The system will automatically update and the TPM warning lamp will extinguish once the updated tire pressures have been received.

The tire pressure will vary with temperature by about 1 psi (6.9 kPa) for every 12°F (6.5°C). This means that when the outside temperature decreases, the tire pressure will decrease. Tire pressure should always be set based on cold inflation tire pressure (placard pressure). This is defined as the tire pressure after a vehicle has not been driven for more than 3 hours - and in outside ambient temperature. The tire pressure will also increase as the vehicle is driven - this is normal and there should be no adjustment for this increased pressure. For a system fault, the system will return to normal once the WCM receives a valid transmission from that sensor location.

_________________
2008 KK Liberty Sport NIGHT OPS EDITION + GILLS
OEM & Custom Skids - Factory Tow Package - Rock Lizard Skink Super Sliders
Prototype JBA 4 Inch Lift - JBA UCA's - Flowmaster Super 44 OR - Whacked Resonator
Jet Stage 2 - RL Gecko Basket Rack - Custom Winch Bumper - Recon 10.5K Winch

Thanks Digger.

"The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off the indicator lamp until the tire pressure is at or above the Low Pressure (lamp) OFF threshold"

I guess what I'm asking is, what is considered low tire pressure? Will the warning light come on if the pressure gets to 32 psi....30 psi, or 25 psi?

I understand about the temp causing the pressure variances and all that. If anything, while I was driving the other day, the pressure should have been higher...due to the 90° temps and the highway speeds. I'm thinking there must have been a glitch in the system or something. Why would the warning light not come back on if the pressure was indeed low?

Paul

_________________
2014 Cherokee Latitude, Deep Cherry Red 2.4L Tigershark for me.
2014 Cherokee Latitude, Billet Silver 3.2L for wifey.
2008 Patriot Sport, Jeep Green for son.

if i remember right, at factory settings, low pressure is set at 26 to 28 psi... but don't quote me

_________________
2008 KK Liberty Sport NIGHT OPS EDITION + GILLS
OEM & Custom Skids - Factory Tow Package - Rock Lizard Skink Super Sliders
Prototype JBA 4 Inch Lift - JBA UCA's - Flowmaster Super 44 OR - Whacked Resonator
Jet Stage 2 - RL Gecko Basket Rack - Custom Winch Bumper - Recon 10.5K Winch

Thanks again Digger.

Duly noted...but not quoted

Paul

_________________
2014 Cherokee Latitude, Deep Cherry Red 2.4L Tigershark for me.
2014 Cherokee Latitude, Billet Silver 3.2L for wifey.
2008 Patriot Sport, Jeep Green for son.

What I read in the Manual said 24lbs will set the light 28lbs will shut of the light.