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Found the TPMS Receiver .... and yes is easy to get to, as it is behind the stereo/air console (held by 4 easy bolts). Thank you #nosurpise
Still unable to find a wiring diagram for my '07 IS250, so I took out the voltmeter, and held the contacts to various combinations, hoping I would see a ~5V current or something when I turned the car on (not the engine)...no luck, besides I still have to guess the Indicator wire, or faith to rec'v the voltage.
P.S. curious as to the two thick gray wires (as every thread I've seen in here, other Lexus/Toyota discussion, don't have that. Awfully, thick for such a pretty based low amp circuitry. Onward .
.
Receiver and model here, for reference:
lol you want this as bad as i do. sorry, i have no useful input or skills. hopefully one day a lexus engineer will tell us. they are on here, i've seen them. smart smart sons of *****es these guys. they sure did acomplish what they were out to do. i cant help but know every other minute that the TPMS is out! i have 3 indicators on the instrument panel telling me. i love it
Unfortunately the "solution" posted for the 4Runner wouldn't work on the IS.
To disable TPMS in the 2IS, my proposed solution would be to disconnect the TPMS ECU and then jump the two brown wires together (pins 2 and 3). This will take the TPMS ECU out of the instrument panel bus loop while maintaining the communication bus for other components. The ECU can be removed or left in place, but it should not be plugged back in.
Not all 2IS models had TPMS, this would basically make the wiring be what it is on cars without TPMS. That said, I haven't tested this and so couldn't say with 100% certainty that the combination meter, etc., would just assume the car doesn't have TPMS if you do this. However, based on some other experience, I suspect it would.
I've never looked into CANbus protocol but I have a hard time believing the BCM is not programmed to look for its TPMS friend. Someone has to tell the gauge cluster it is ok to cancel that error msg so my gut says the tpms module needs to be present and happy for all the friends on the bus to be happy and not pass errors along.
Abstract. Has anyone ever tried to use one sensor at all 4 ID locations? As in, provide the TPMS sensor the same ID for all 4 positions then just keep one sensor alive in the spare or something like that?
I'd guess Techstream would throw a flag up saying no but the question is, does the TPMS receiver know or care?
Another option is to take your used dead sensors, power them with another source and replace the pressure sensor input with a fixed value.
The pressure sensor output voltage could fixed with a resistor for all practical purposes and the pressure always reporting 36psi. Then battery power the unit and at least the car itself remains stock.
Unfortunately the "solution" posted for the 4Runner wouldn't work on the IS.
To disable TPMS in the 2IS, my proposed solution would be to disconnect the TPMS ECU and then jump the two brown wires together (pins 2 and 3). This will take the TPMS ECU out of the instrument panel bus loop while maintaining the communication bus for other components. The ECU can be removed or left in place, but it should not be plugged back in.
Not all 2IS models had TPMS, this would basically make the wiring be what it is on cars without TPMS. That said, I haven't tested this and so couldn't say with 100% certainty that the combination meter, etc., would just assume the car doesn't have TPMS if you do this. However, based on some other experience, I suspect it would.
Jeff
Thanks Jeff... I have the contacts all setup on a 'terminal bridge' will test current, and attempt a bridge and monitor the current. Will report back replete with pictures.
Even I fail... in the ease of taking everything out... I found 2 $1 bills, a slew of coins, and an $11.40 subway (BART in San Francisco) card. So, ... from the mud grows a lotus.... Lexus.
I've never looked into CANbus protocol but I have a hard time believing the BCM is not programmed to look for its TPMS friend. Someone has to tell the gauge cluster it is ok to cancel that error msg so my gut says the tpms module needs to be present and happy for all the friends on the bus to be happy and not pass errors along.
Not always the case, but in my experience Lexus often builds their cars with modularity in such a way that options can be added or removed without needing things programmed differently. If an ECU is present, those functions are available/checked, if it isn't, it is ignored. Again, I haven't tried with the TPMS at all but it's worth trying and if it does work, it would be the best way to disable TPMS without question, so it's worth trying.
If the IS always had TPMS, I would be more suspect of removing it, but since not all 2IS models came with TPMS, it's more likely. Still not guaranteed, there certainly are times when this is not the case, for example the differences in DRL programming between Canada and the US.
Thanks for sharing. It will be good for us to know what is happening at that level. Of course as we know, that doesn't mean they didn't change it over the years so it will be good to document what options and modules these modifications are done on.
Previously I used to do component level troubleshootimg I2C devices on a common bus and it was really all about the logic (ones and zeros) defining the operation of said device as to weather or not exceptions are allowed.
Thanks Jeff... I have the contacts all setup on a 'terminal bridge' will test current, and attempt a bridge and monitor the current. Will report back replete with pictures.
Even I fail... in the ease of taking everything out... I found 2 $1 bills, a slew of coins, and an $11.40 subway (BART in San Francisco) card. So, ... from the mud grows a lotus.... Lexus.
^^ lol
As a safety precaution I perform any/all short circuiting using a 12v incandescent test lamp. So if something is not mean to shorted, the lamp lights and nothing burns up. Its cheap insurance when so many delicate wires need to survive.
I've never looked into CANbus protocol but I have a hard time believing the BCM is not programmed to look for its TPMS friend. Someone has to tell the gauge cluster it is ok to cancel that error msg so my gut says the tpms module needs to be present and happy for all the friends on the bus to be happy and not pass errors along.
Abstract. Has anyone ever tried to use one sensor at all 4 ID locations? As in, provide the TPMS sensor the same ID for all 4 positions then just keep one sensor alive in the spare or something like that?
I'd guess Techstream would throw a flag up saying no but the question is, does the TPMS receiver know or care?
Another option is to take your used dead sensors, power them with another source and replace the pressure sensor input with a fixed value.
The pressure sensor output voltage could fixed with a resistor for all practical purposes and the pressure always reporting 36psi. Then battery power the unit and at least the car itself remains stock.
Just throwing out ideas.
i really have no knowledge of anything to have an opinion, but if hes saying lexus is set up so that its just a matter of if its there great if its not great. the car wont miss it because nothing has to be changed. any error loop or whatever the word is wouldn't exist because you've reset the cpu and theres no TPMS sending anything lets hope at least.
ive never seen anything about just having 1 sensor programmed for each slot, id have to think if it were viable id hae come across at least something.
as far as adding resisters and that space talk, lol nothing i can do.
^^ lol
As a safety precaution I perform any/all short circuiting using a 12v incandescent test lamp. So if something is not mean to shorted, the lamp lights and nothing burns up. Its cheap insurance when so many delicate wires need to survive.
GL!
i have a test lamp, but i not understanding what your saying to do with it? im lopping the 2 brown wires, correct? i not testing anything for current?
Last edited by bryceis250; 03-05-19 at 09:47 PM.
Reason: change
thanks a whole lot for your time jeff! its real cold here right now but soon as weather brakes im gonna try. whats the technical name for the little plastic jumper thing? ive got to go find one
i have a test lamp, but i not understanding what your saying to do with it? im lopping the 2 brown wires, correct? i not testing anything for current?
When probing into circuits where one intends to change its function and we don't know the details, the safe choice is using a test lamp if for example you intend to:
- remove a component and jumper a wire from one place to another.
- jumper a connection to ground.
- jumper a connection to +12v.
If you take a solid wire of zero ohms and insert it where energy is present this can cause a short where the load is high and either a fuse burns open or something else burns.
By using a test lamp instead of a zero ohm wire, you won't burn anything up because it is not a direct short as the incandescent lamp will light telling you there is current flow. A barely lit lamp may be fine. One that glows at full strength tells you the two points have different potentials.
The benefit of this over a digital meter reading volts is it tells you there is current flow.
Make sense?
I came across a thread on the 3GS forum where someone tried a few different methods (including removing the TPMS ECU from the communication bus) without avail. Based on that I am thinking we may be in a bit of a pickle, as removing the ECU needs to be combined with an appropriate body ECU. A Korean-spec body ECU would take care of that, however there are other differences between Korean-spec and USA-spec that you'd need to live with as well.
03-03-19, 09:21 PM
