Interior LED Lighting?

I just wanted to add a note here to detail my experience. I also changed out all my interior lights for LEDs, as well as some of the exterior ones. I used the same parts listed by Antiflash in post #139 in this thread. I did this within a month or two of buying my car. Since then, I've had issues with the tire pressure light - it would come on flashing after 20 minutes of driving, indicating a problem with the system and not low tire pressure. I took the car in to the dealer a total of 7 times and they could not fix it. They replaced almost every part of the tire pressure monitoring system to no avail. They even had an engineer come out from Toyota corporate to look at the car.

At last, I filed an arbitration request to get a new car under my state's lemon laws. I was promptly contacted by Toyota and the asked for one last attempt to fix the problem. They said if they couldn't fix it, they would give me a new car. I agreed to let them have one more attempt at it. A further wrinkle in my case was that my wife and I have identical cars (except for paint color). I also replaced all the lights with LEDs in her car as well. She was not experiencing the tire pressure light problem.

They kept the car for two weeks. After lots of investigation and test driving, they discovered the problem: the LEDs I used for the license plate lights were causing interference with the tire pressure signals. (Apparently the receiver for the signals in located near the license plate.) They replaced the LEDs with standard bulbs and the problem went away.

Some additional findings:

- The problem only occurred with the lights were on. Since my wife rarely drives her car when it's dark out, she never experienced the problem. We did a test, driving her car with the lights on, and the problem showed up for her as well.

- The tire pressure system runs a check every 20 minutes, which is why it takes that long for the tire pressure light to start flashing.

- the Toyota engineers checked this message thread while researching the problem

- Toyota was fantastic during this whole process. They provided me with a rental car at no charge. During their test drives, a rock was kicked up from the road and chipped my windshield. They replaced it at no charge. They were perfectly willing to replace my car if they couldn't solve the problem. Even though the whole issue turned out to be caused by me and my modifications to the car, they did not ask me to pay for anything.

Anyway, with so many people replacing the bulbs with LEDs, I just wanted to post this for future reference. If anyone encounters a problem with their tire pressure light, try putting standard bulbs back in the license plate lights. I am also curious to know if anyone who has LEDs in that location is experiencing this problem.

 

Let us know when it starts acting up again. There are a LOT of people on this forum that have LED lighting in their car, and it does NOT cause the problem with TPMS for them. However, for those of us that have it - it's like fighting World War III and some of us have just surrendered, accepting the fact that we will need to put black electrical tape over the light since the TPMS will never work.

 

Are you guys talking about LED interior lighting as in the dashboard lighting, or map lights, dome lights, etc etc?

Sorry I didn't feel like reading through 17 pages.

 

For me, I did a bit of both.. I did all the interior lights - dome, doors, map, cargo (not the dashboard or footwells though), plus the backup lights, the license plate lights, and the front headlight marker lights. Antiflash has a post listing all the lights he changed out on page 14 of this thread.

 

Well I've retrofitted domes, doors, map, cargo, and license plate lights, and I've had no problems so far. Of course this is a Gen II I'm talking about.

The license plate LEDs are my proudest mod; it was soooo difficult hahaha! I hope I never have to replace them again. 50,000 hours baby!! *crosses fingers*

 

Ohh yes, I remember reading antiflash's post when I was researching LEDs myself. I used superbrightleds.com as he recommended.

 

THANK YOU

I've been having the EXACT same problem. You should have seen a thread I started. It had several pages. Toyota replaced almost everything that had to do with my TPMS system as well. So it's the LED lights in my license plate area huh? DAMN! I would have never guessed it would be THOSE LED's. I love the look of the LED's though.. I don't wanna take em out. I really should though. Does anyone have an alternative to the LED's for the license plate rear area? Maybe some "white" bulbs?

Shaun, you have finally explained why my TPMS light has been messing up since my transition to LED lights. Thank you! I gave up on my dealer and just thought I'd deal with it. I'm glad I read this thread :rockon:

Link to my thread: http://priuschat.com/forums/gen-iii...-tire-pressure-warning-light-dead-sensor.html

 

Just to confirm - I just took my LED's out of license plate and replaced with original bulbs - NO TPMS BS this time. Thank you again for confirming this WAS the issue of my problem. I have to admit, it looks ugly - but oh well.

 

Glad to help!! It was driving me crazy too! Glad to know I wasn't the only one having this problem.

One test I plan on doing this weekend is to get one of those snap-on ferrite cores and put it on the power line to the light, then put the LED back in to see if the problem still occurs. That might be enough to damp out the RF interference.

 

So let me get this straight - Retrofitting your license plate with LEDs on a Gen III may cause your TPMS warning to light on?

That is so weird. I dont know what's worse now: Cutting up your hand to try to install LED license plates on a Gen II or this.

 

Okay great idea! Please let me know if that is successful for you. I really miss my LED license plate lights - but if they have to go for good it's alright. Seriously.. I was on the SAME road with you regarding Toyota Corporate and everything. I finally just gave up though. I'm glad you went through with it and kept strong. I appreciate it. Once again, lemme know if those cores work!

It sure is weird huh? Made no since to me, but I guess it could happen!

 

I've had LEDs bulbs in all lighting positions other than the turn signals for over 15 months now. I haven't had any issues with faulty TPMS warnings. And I do drive a lot at night, with my nightly commute being roughly an hour long.

 

Maybe they're a specific type then? Which ones do you run in the license plate area? I run "Cool White WHP5 SMD" bulbs from Superbightleds.com They have 5 diodes on each "bulb". Maybe it is specific to the type we use?

 

I'm using the same bulbs as you in the same place. But again it's a different car, different game.

 

That's true. I think the 2009's are okay with these bulbs - but for some reason the 2010's are not. I miss them already . Oh well, I'd rather have the LED's out than the TPMS annoying me every 20 minutes while I drive. So I can deal with it.

 

I was using the same bulbs up to about one month ago. The only reason I changed them out was because of a flickering issue with one of the bulbs. I've since moved onto ones from JDM Toys (eBay seller).

 

I've done a bit more research into this. It seems the super bright LEDs work by using many LEDs on a single base. They then use a control circuit to control the current to the LEDs to push it to the limit, then cycle it off and on, faster than the human eye can detect. The oscillation is what generates the RF noise.

So I tried a couple of methods this weekend to try to reduce that noise. My first attempt was to put a ferrite choke on the power cable:



That didn't work. My TPMS light still came on after 20 minutes of driving with the lights on. My next attempt was to cover the socket with a couple layers of heavy duty aluminum foil. I tried to make sure the foil had contact with the metal frame of the car so it would be grounded:



That didn't work either. I then tried both the ferrite and the tinfoil at the same time. That also didn't work.

Not sure what to try next. I'm thinking I might need to try some non-super bright LEDs..

 

Do you know the part number you used?

 

I'm currently using these above the license plate:
White 12 SMD LED License Plate Lights Bulbs 168 194 #C3 - eBay (item 380307493698 end time Jan-19-11 16:38:32 PST)

 

Been thinking about my next step. It seems I need to determine if the RF interference is coming through the air or through the power line. I would have thought the ferrite would have ruled out the power line case, but maybe not. So I was planning on getting a 12V battery and powering the lights with that and seeing if I still got the interference.. But..

Since we've got the same car and you aren't having the problem, I may just try getting these instead. They're cheap enough.. Thanks!