DavidinCT

Hey all,

Every one of my LS's had their "cold" issues, my even my old LS430, if it dropped below 10 outside, the ML amp would not come on. That required me to drive the car for a bit, pull over, shut off the car, turn it back on and it would work again. When it was really cold, it needed a lot of time to "warm up"

So, the driving in the snow for a while (under 10 degrees out), the "Check tire Pressure system" came on, then after it warmed up, it went away...

This current storm put it out again (for almost a week and 1/2 it's been under 20 out, and the last 5 days under 10), and now it's not going away. So my car always has the (!) on the dash and the ANNOYING yellow triangle.

Is there a way to "reset" the system to see if t comes back ? Will techstream show the issues with it ?

It's driving me nuts, thanks !!

Chuckinnj

Check ALL your tires with a ACCURATE (preferably digital) tire gauge when the tires are cold and fill to the recommended pressure...... Drive the car for a few miles and hopefully the ! goes off.
Get back to us if this does not work.

tofuprod

^Exactly as said above. Obviously it goes without saying the tires will warm up no matter the temps as you drive, mine in the late subzero temps I've had, when I start up the LS as it sits outside, is at 32 PSI all the way around. After a few minutes of local driving it goes to roughly 37 PSI.

Prior to the sub zero temps since we were at roughly 20 degrees for a few weeks, I inflated my tires up from 32 to 40 to combat the change, thus my readings above.

I also bumped up the spare to 40 as well since the TPMS in there would go off too if it dropped below I think ~25 or something PSI.

You could just be right at the threshold where the TPMS thinks you're low vs. where you're not by 'it's' readings.

Good luck.

Dave144239

My sister-in-law was complaining about the low tire pressure warning in her RAV-4, and when I checked the spare tire it was down to 24lbs. With our overnight temps in single digits, it's not surprising to see tire pressures drop,

jmcraney

There is no owner/operator accessible "reset" for your car's TPMS. The TPMS is reset each time the ignition is cycled.

The indications that you described likely mean that one or more of the tires is under inflated or that one or more of the low pressure warning thresholds is set too high, or a combination of under inflation and maladjusted thresholds.

These cars monitor 5 tires so don't forget to tend to that spare.

213374U

Ummm....



HOWEVER.... do not use that button to make the light go away, you need to add air to your tires. As others said, get a good digital gauge and fill your tires to the proper PSI, then use that button to make sure you TPMS is benchmarked to the right PSI. Only using that button without adding air will adjust your benchmark too low and it won't come on even if your tires become dangerously low.

jmcraney

This is not a "reset" button - it is a TPMS BENCHMARK SET button.

DavidinCT

I know this part pretty well. When it started getting cold, my spare went down to 24 psi... and the dash gave me "Check tire pressure" but, this error is NOT the same, it's "Check tire Pressure system", like it's showing there is a problem with the TPS system, not the tires.

I'll try to check the levels tonight and see if I have any luck. I have a Cheap-o gage digital one that I keep in my car (replacing it soon)...it's normally with in 1 PSI as they TPS system...

Thanks ! I'll post back if it works or not.

Spudo769

It has been below zero here for much of the last week. I had recently gotten an 07 LS. In November I had a local Discount Tire mount my winter wheels tires on my LS. They had come off my prior Regal, and one of the selling points to me was that I could swap the wheels. However the TPMS monitors in the wheels wouldn't work with the Lexus. I paid DT about $130 to replace and install all new monitors. All was well, the TPMS lights were all off. On Christmas Day I headed out to the airport (about 15 minutes) to pick up a family member. After about half hour of the car being in the operation I got the low tire warning and also the Service TPMS systems lights. AT this point it would not show me the screen with the 5 numbers for tire pressures. The next day I took it in to DT. They 'relearned' the monitors with their tool and I drove off. About 10 minutes later the same thing happened. Disgusted I just went home, thinking that I would set up a follow up appointment where they could do a thorough check, as I was expecting it to be the spare which hadn't ever been disturbed (original factory tire). The next day the lights were on again, and I had to drive about 30 miles for work. About 25 miles in the lights went off on their own, and I could see all the numbers again. Now each time I start it I scroll to the numbers. The middle of the 5 seems to take a long time searching before it eventually gets the number. I no longer think it is the spare, as that one is typically the bottom number. Since then the lights haven't come back on but still takes a lot of time finding the middle number pressure. I think after a long time searching without success eventually triggers the system needing service light. So, if it happens more frequently I will be going back to DT where they will have to see if one of the new sensors has an issue. Not sure if this is cold weather related, but no issues until this cold snap.

jmcraney

You seem to have two different things going on.

The system failure is typically caused by a non-reporting sensor. Non-reporting sensors are usually caused by broken or defective sensors that have a depleted battery or are damaged during installation or tire repair. When the TPMS goes 20 minutes, exactly 20 minutes, from the last pressure report from any sensor the system goes into failure mode. So, if you are driving less than 20 minutes, no failure indications. If the sensor is dead when you start your car, then when you have been in operation, without turning the ignition off, for 20, the system will give a failure indication. As soon as you cycle the ignition it will reset the TPMS and clear the failure indication. If the sensor quits reporting while the car is in operation then the failure indication comes on 20 minutes after the last report. Sensors that are slow reporting are not a problem as long as the don't go more than 20 minutes. Radio Frequency Interference can cause sensors to not report however that is rare. RFI is typically local and will not be a problem after the car leaves the area. It is possible to have RFI that follows the car, from electronic add-ons, such as radar detectors and power converters.

The low pressure warnings are caused by sensors that are reporting pressures that are below the car's warning thresholds.

DavidinCT

Ok that makes sense.. This will show up within 5 seconds of starting the car...this started about 3-4 days ago but, it's been under 10 outside (has not gone over)

I drive an hour to work and an hour home, depending on traffic. So the 20 min thing is not an issue. So, it's possible that a battery failed while it's this cold ? They tires have not been touched from buying the car in May 2017, and they are still in very good shape with no plans on replacing any time soon.

There has been no addons the car accept for the Dball remote start install but, that was in summer time.

So if we lean towards a failed battery (no other changes in the car besides driving it while this started), how can I figure out exactly what tire is causing the issue ? Will techstream show more details on this ?

What else would you try to troubleshoot this one ? Or should I just deal with it till it gets a little warmer and see if it was "cold" that causes it.

jmcraney

It seems to me that the most likely cause of your problem is under-inflated tire or tires. Or, warning threshold or thresholds that are set too high.

Defective sensors - bad batteries or broken - do not report low pressures. They don't report.

You need to adjust your tire pressures and set the warning thresholds to appropriate levels.

Spudo769

I think my issue is a sensor that is slow to report, sometimes past the 20 minute mark to trigger the System and low tire lights. Tomorrow I am taking a 2 hour trip, so interested to see if the slow sensor comes to. Since 4 ​​​​are new i will still be setting up an appointment with the installer, since 4 out of 5 sensors work pretty quickly and the middle one doesn't. Is there an easy way to match up the 5 numbers on the screen with the actual sensors? I have seen people say the trunk is on top, mine seems to be the bottom one. No one has ever mentioned the middle one, like my issue.

sha4000

iTrader: (1)

Techstream will show the dead sensor. The only way to see which sensor correlates to what position on the dash is to let air out of the tires one at a time and watch the display to see which one drops.

Gbp

I recently had the low tire pressure warning message. I suspected that it was the spare because the PSI reading for the 4 other tires when cold (40-50 F outside temperature when starting the engine) were 31-32, and the other tire was at 29. The thing is that when the car started under warmer conditions and the lower tire was at 31 (or maybe 32), I still had the warning message and lights.

I finally added a few more pounds of pressure to the spare, started the car, and the message lights were gone. It’s as if the higher ambient temperature wasn’t sufficient to clear the error, and that the tire needed inflating to do this.