i have 05 rx330 and the tires pressure light never came on even when one of the tire was at 15 psi. i cant depend on the system anymore because when i check the pressure they're usually really low. do you guys think something wrong with the system?

 

I think you have already reached that conclusion.

Stop bye at your dealership. I hope you have caught this before your warranty expires. Could be as simple as blown bulb.

Salim

 

are the 05's direct or indirect based - I don't recall
(do they have a sensor in the wheel or do they go by the abs speed sensor?)

If they are indirect (ABS based), then you can't expect it to know a tire is low unless you are traveling at a certain speed... now, if it's direct (meaning they each have a sensor) then there is no excuse... I usually find them to be quite accurate...

 

what do you mean direct or indirect? if they're indirect what speed do you have to travel for them to work? can someone explain please?

 

direct - sensor in each wheel - typically marked by an aluminum valve stem
indirect - abs speed sensor calculates difference in wheel speed, and looks at a reference when the system was calibrated...

20mph is typically the minimum for them to operate...

 

indirect does not have sensor in the tire transmitting pressure to the computer. it calculates, based on wheel speed, and frequency it one wheel is different than the rest, sooo if all for tires are flat=no light on dash, if all four tires are close ie. 20,24,25,26=no light on dash, aswell bumpy roads, bad wheel bearings, mismatched tires can trigger a false light on dash.
Direct type actually sends a pressure to the computer so it really knows specifically what the pressure is.

 

im sure i was traveling over 20mph when the tire was low, but no lights on dash board were ever came on. something must be wrong

 

I have the 400H but I am guessing it uses the same system as your car. I got the car a while ago but I have just gotten around to reading the book. I recall reading something about filling all the tires with the correct cold pressure and then you need to do something to calibrate the system. I don't have my book handy but I am wondering if you did the calibration thing?

 

thank you, i've never read the manual and had no idea that i have to calibrate the system. i will pull out the manual and see if i can do something about it.

 

ok brought the vehicle to the dealer today and was told everything is normal, so i ask for manager and we let the air out one of the tire to 15psi and drive but no lights came on. dealer called around and asked but no ones really knew what was wrong with it. they reset the program and told me to drive at a constant speed for 20 mins for the program to memory something. I tested it at 15psi after an hour drove home from the dealer but no luck. what should i do now?

 

Take it back to the dealer . . . for some reason either the tire pressure computer is not triggering the low tire light, or the computer is not receiving data from the sensors. Your dealer should either be able to trace this, or at least replace components until correct performance is observed.

 

I have to laugh (not at you) about these manuals. More like a serious old school novel. Seriously, this thing is thick and, at times boring, but there is a wealth of information in the manual. I have to credit my wife for reading it. She took it out, after we bought the car and drove home, and started reading it. LOTS OF STUFF that you won't find in other places. At times, she would actually go sit in the car, turn the key on and follow up on lights, bells, whistles and such. She recently had a visibly low tire and then, when starting the car, the low tire pressure warning came on. She had run over a screw so we had a steady, slow leak.

As to the dealer, take it back as many times as you need to in order to get the problem fixed. If necessary, elevate the issue to Lexus USA and see how long it takes the dealership to fix the problem. Or, drop the car off with them, ask for a loaner and then have them call you when your car is fixed. I suspect that it won't take long that way.

I thought it was brilliant to let the air out of the tire to 15 psi and then put the tech in the car. Can't argue with that or say "we can't duplicate the problem."

Gary
'05 330

 

Great idea on the Tech riding with you, they should do that as SOP. Granting you have found a good TECH. Boy they pay them like crazy. They earn like $40 an hour.

 

correction, they earn $30-$40 per BOOK hour... which means if it takes them an hour to do a 3 hour job, they just made $90- $120 in one hour alone...

 

If anyone took 1 hour to do a 3 hour job, I would be suspicious of them taking shortcuts and omitting something. Now, if they took 2-1/2 hours on a 3 hour job, that's would be more reasonable.

But then again, the consumer would never know the actual time it took, right?


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