tpms NOT working, must be crazy

T4RBoarder

T4RBoarder

New member
Call me crazy but after reading a ton of threads I would think most people really wanna ditch their TPMS system but I really was excited that this truck had it when I bought it. Well since I have had it I noticed the front passenger side tire was lookin' a little low so I decided to check the pressure tonight and sure enough it was low at 25 psi but no light was on. Decided to hop in the truck and check it out and sure enough the light did not come on to self-test when I turned the ignition :redbrick:.

What are the chances that the PO decided to disable the TPMS/how in depth would it be to get it back and working? (I know that is probably too broad of a question cause so many things could be done).

:thanks:
 
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You posted this in the 4th gen forum, so I can only assume you have a 4th gen, right? Your signature lists your 4Runners as sold and an FJ Cruiser as current.... so what year 4Runner are you talking about? Or is it the FJ?
 
I know that in my '07 Mustang that TPMS cannot be disabled; only "fooled". Also, even with a low tire pressure, I believe it takes a certain amount (distance) of driving before the TPMS indicator will come on. Of course, the accuracy of an individual sensor COULD be off such that it may not set off until 24 PSI or lower (if I recall, they're set forabout 26 PSI).

Maybe you could let another few PSI out of the tire and see if it trips it. Of course, the questio remains; why is the tire low in the first place?

EDIT: OK, it took me awhile to finish my post and I just saw your previous post that it's for an '05. Was TPMS even offered in '05? I thought it didn't become required until '07.
 
see I thought I would do that but the manual specifically states the light would come on to self-check and then go off unless there was a problem. I don't even get that much.
 
Nuke said:
I know that in my '07 Mustang that TPMS cannot be disabled; only "fooled". Also, even with a low tire pressure, I believe it takes a certain amount (distance) of driving before the TPMS indicator will come on. Of course, the accuracy of an individual sensor COULD be off such that it may not set off until 24 PSI or lower (if I recall, they're set forabout 26 PSI).

Maybe you could let another few PSI out of the tire and see if it trips it. Of course, the questio remains; why is the tire low in the first place?

EDIT: OK, it took me awhile to finish my post and I just saw your previous post that it's for an '05. Was TPMS even offered in '05? I thought it didn't become required until '07.
Click to expand...

4Runners got TPMS in 2004, that was the first year.

BTW, you can fool the system or disable the system. But both basically serve the same function...
 
T4RBoarder said:
see I thought I would do that but the manual specifically states the light would come on to self-check and then go off unless there was a problem. I don't even get that much.
Click to expand...

It might just be a blown bulb in the instrument cluster if you're not getting the light on momentarily just after start-up.
 
Just thought of something...check to see if the valve stems are metal. If they aren't, then the previous owner definitely removed the sensors and probably disabled the dashboard light.
 
yup, valve stems are metal....is there any fuse I can pull to confuse the system to see if I can get it to do anything or is my next step just pull out the cluster/I thought that bulb was an LED?
 
T4RBoarder said:
yup, valve stems are metal....is there any fuse I can pull to confuse the system to see if I can get it to do anything or is my next step just pull out the cluster/I thought that bulb was an LED?
Click to expand...

Don't go digging into the cluster.
Do you get the light when you first turn the vehicle on (when all the lights go through the start sequence?)
(Edit: Misread the OP. Read closer that there is no light)
 
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T4RBoarder said:
Decided to hop in the truck and check it out and sure enough the light did not come on to self-test when I turned the ignition :redbrick:.

What are the chances that the PO decided to disable the TPMS/how in depth would it be to get it back and working? (I know that is probably too broad of a question cause so many things could be done).

:thanks:
Click to expand...

Its possible. The easiest check is to remove the panel below the glove box. The tpms module us right there. Any tampering will be visible.
 
from what I can see the module looks untampered with and the wires are untouched all the way up into the dash....ugh. Nothing is an easy yes/no

e3035e7e.jpg~original
 
T4RBoarder said:
from what I can see the module looks untampered with and the wires are untouched all the way up into the dash....ugh. Nothing is an easy yes/no

e3035e7e.jpg~original
Click to expand...

I'm telling ya...it's probably just a blown bulb in the instrument cluster. It happens...and no, they are not LEDs.
 
If someone has the schematic for the TPMS, I can tell you how to do a simple check with a test light or volt meter (if you have one) to see if the bulb is out or not. It's just a matter of finding the correct wire and seeing if you get momentary voltage to the bulb upon turning on the ignition. In other words, the bulb test during start-up requires a few seconds of voltage that can easily be seen with a test light or volt meter. If the voltage is present and the bulb doesn't illuminate, the odds are probably about 99% that the bulb is blown.
 
Okay, I found a partial schematic for the TPMS. It would have helped if I had all the pages but still...it appears that you should have 12 volts at the Voilet/Red wire for a few seconds after turning the ignition on. This wire goes from the tire pressure monitor ECU to the combination meter. It goes through a connector (J29) out of the tire pressure monitor ECU and then to the combination meter where it signals the TPMS dash light.
 
Ok, spent the afternoon with a buddy at the dealership to fix some of the customization settings and we checked the sensors and they were all reading correct pressures (spare was low) but no tripped light or self-check still.

New problem, tried to order a new bulb but when they pulled up the parts list no separate bulbs are listed for the instrument cluster....anyone got the bulb P#?
 
update: the search is over...the bulb is an LED and I don't want to go that in depth to try and fix a bulb that could or could not be the problem, I'll just deal with it :moping:
 
A lot of people don't want to deal with the TPMS especially when they upgrade tires/wheels and don't want the sensors in the new tires. It's a useful feature, but some people don't like it. Doesn't bother me either way. I know my brother ended up just cutting the bulb off the board to get rid of the light.
 
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