Rustito

My tire pressure light has come on - it did once before about 8 months ago. All tire (not flatruns) pressures seem fine (between 34-38 not cold). Tires were rotated by dealer not too long ago. Any suggestions? Do I need to reset the pressure light - understand it is somewhere under driver side dash? Previously I think I added air and light went off. But this time tires don't need air.

iolmaster

iTrader: (1)

It is possible that a battery in one of the sensors has gone bad. All of us will have to replace the sensors at some time.
The batteries are not replaceable. You have about 9 years on yours and it is about the right time.

Harold57

I don't believe that there is a reset button for the TPS. If all the tire pressures are fine, most likely you have a sensor gone bad, just like iolmaster said. I've replaced most of mine now on my 2002.

Rustito

Thanks for the input. If it is the sensors is there a problem driving the car with tire pressure light on until I get a chance to get sensors checked (in a month or so) as long as the tire pressure is OK? Just want to make sure this won't cause some other issues - if it is the sensors.

iolmaster

iTrader: (1)

No other issues. You will be fine.

Rustito

The guy at my local gas station said he could check for bad tire sensors and replace. Is this something I should have dealer do?

In January tire pressure light was on so dealer "reset" and it went off but is back on now - haven't driven the car for a number of months. I looked under dash above gas pedal but saw no switches to reset pressure light.

Also - Car has had several sets of tires and I noticed that the little switch on the right side of glove box for registering tire sensor codes in the 2004s is set to "main" vs. second. I read in manual that you should only use main for first set of registered tires. I tried switching it and pressure light is still on. All tires are even cold pressure of 33. Not sure if I should switch to second and try driving and see if that is it.

Bottom line as has been said is a sensor is bad - so can my gas station guy who says he can test and replace an OK solution vs dealer?

OBP

The TPMS system in our SCs is not that user friendly. Either your gas station guy really knows about our TPMS which is different from quite a few other Lexus and Toyota systems or you are taking a risk. My other cars have simpler systems which make this SC tpms a real pain to deal with.

FLYCT

Before you do anything that costs you money set the threshold where he light goes on.

Check out posting #28 of this thread for a picture of the reset switch and instructions on how to reset. https://www.clublexus.com/forums/sc-...n-later-2.html

JR

Rustito

I did look for the reset button and didn't see. Do the 2004 SCs have same reset button? I will look again.

FLYCT

I don't know if it"s the same for the 2004. My 07 and 08 both have it. Perhaps someone with a 2004 can chime in

I swore mine didn't have it until my wife found mine. That is why I posted the picture so anyone else can use it as a reference to find theirs. You have to get down real low to find the reset button.

JR

FLYCT

Go to Page 242 of the 2004 SC430 manual
http://drivers.lexus.com/t3Portal/do.../sec_04-03.pdf

JR

Rustito

FLYCT - Thanks for sticking with me on this. But still no luck. Page 242 of SC430 2004 manual is about battery jump starting procedure. I also looked for the reset button to initialize the tire pressure warning system as per the link you posted, however my interior at that spot does not look the same. Again I searched around that area and under as per your pic but still can't find the reset button. I might call the dealer tomorrow but I'm sure they will say to bring it in. I am getting close to that, however, I can see this ending up in big expense to replace sensors. Maybe no way around that.

The posts have been helpful. But still not fix on my own - seems so simple but so far. Anyone with a 2004 SC who has been down this road???

Rustito

Just read that the 04 SC430 has one of the early sensors that Lexus used and there is no reset button for the 04 the way there is for the later models.

FlopTop04

I have a 2004 SC430 and have had issues with the TPMS. Here a few things I have found out :

1. As mentioned above, it is a unique TPMS system and other than a Lexus dealer, I have found no one with the correct
equipment to test / troubleshoot the system.

2. As you found out, there is no Reset button under the dash to reset the sensors.

3. It is possible to completely disable the system by unplugging the two harnesses to the control unit ( under the radio ).

4. While not for the faint-hearted, it is possible to replace the battery ( CR2477N ) in the wheel sensor unit. They last for
5 - 10 years. There is a post with pictures on this process.

5. The complete wheel sensor unit goes for > $100 at the dealer, plus installation. They can be found on-line, new for
$60.

6. Just remember there are four different wheel sensor units ( Red, Blue, White and Yellow ) so you must determine
which one is bad and then determine what color it is. That would require a trip to the dealer to determine which wheel
is not working, a tire dismount to get the color, a tire remount, order the sensor, then another dismount, sensor
replacement, and tire remount ( with possible wheel re-balancing in between ).

I paid $270 for one sensor replacement at the local dealer ( done in a few hours ). For $320 you could buy all four sensors,
go to your local tire shop and be done with it. However, the dealer said that re-programming or re-calibration was
necessary after replacement so... ( I can't verify if that statement is accurate. )

I don't have run-flats, but I do have the spare tire kit. Even with this set-up, I still prefer to keep the TPMS system fully
operational.

Another option :
There are after-market TPMS systems out there. You could unplug the Lexus system and switch over to one of these.
There are some that have a small display that will give you the exact tire pressure for each wheel. System price is less
than having the dealer replace one sensor. There is a post with pictures on after-market sensors.

Rustito

Hi Flop Top - Greatly appreciate your detailed post - it has helped me come to the decision that the dealer is the best choice for me at this point. It is a pain and I now see that these sensors might each go as they are reaching their useful life and replacing the battery is something beyond what I am prepared to mess with - or disabling.

I do get that with flat runs these sensors are impt. as you often don't know if a tire has gone bad the same way you do with regular tires. So these sensors pick up on that before you are in trouble. But with regular tires (which I have) these sensors don't seem that useful although I do see why some people do like the extra protection. I don't drive with a spare in my SC - just an air pressure kit to pump up a tire that might be low on the road. But I do check my tires. So I would be fine without sensors but that is not something dealers are authorized to do so that is out for me.

Hope others have learned as much as I have abt this issue and the options. At least I won't be searching for the reset button again tomorrow!!!