T &sr180 Tpms How To Turn Off..

[stewyinpagham]

Fingers crossed the T180 tyre lamp issue may be solved.

http://www.yarisworld.com/forums/showthread.php?t=11058 Has the sect=ret been discovered..

I am going to try this shortly unless anyone with more savvy like SHCM tells me different or I've missed this in the past.Oh for a wiring schematic!

JUMP TO POST 34

[shcm]

http://www.toyotaownersclub.com/forums/index.php?showtopic=119054&view=findpost&p=1075751

[stewyinpagham]

Sorry SHCM, I don't know how I missed the posts above. Senior moment caused by excesses of alcohol..

Ok, so with the engine running and the TPMS brain connected and not showing a warning, I need to measure the voltage between;

+V Pin#1 and Pink pin#5

and

0V Pin#9 and Pink pin#5

I will let you know..

[stewyinpagham]

Well I would if I could find the blinking thing.. Any Ideas on the location of the TPMS gismo?

I thought it was at the bottom of the o/s 'A' piller? There is a 'gismo' behind the bonnet release lever. I've hooked out the OBD connector and I see a 'pink' wire but to get to it looks like the knee air-bag has to come out?

[shcm]

Yeah, the knee bag probably does have to come out:

You could possibly tackle it from the instrument pack:

Detach the 4 clips, 6 claws and remove the instrument cluster finish panel:

Remove the 2 screws. Pull the combination meter as indicated by the arrow in the illustration to detach the 2 clips.

Whether there is enough harness to pull out, leaving the pack connected and get a probe down the back of the connector to measure voltage, I don't know.

Think you are looking for pin 5 on the pack connector. There is possibly more than one pink wire, but hopefully the position in the back of the connector should give it away. At least you're having a go, which is nice to see.

EDIT: Here you go:

ANOTHER EDIT:

If you can measure voltage between pin 33 (GND) and pin 5, that will give the voltage at the TIRE pin when the light is off. In fact, if your DVM sample rate is fast enough (how long is the light on at ign on?) you can probably find out voltage for light on and light off, by watching what is starts at when you "ign on" (light on for initial system check?) and then what it changes to, when the light goes out.

Don't have to use pin 33, any body/chassis GND would probably be good enough.

[stewyinpagham]

I'le have a go with test tool 'accessory No1' a bent paperclip and try to access the connector without removing the air-bag.

Just so I know, is it a case of just unplugging the Airbag to stop deployment or is there more to it?

[shcm]

The recommendation for airbags is to disconnect Battery neg then wait 90 seconds before touching any of the airbag system. I really shouldn't say anything else.

Once the airbag squid connector is disconnected, a shorting bar inside the connector on the squib/(airbag) side should connect the two squib pins together as a prevention of the disconnected airbag deploying due to say ESD (electrostatic discharge) or similar.

If you power up the vehicle systems with the airbag disconnected, you'll probably get a DTC in the airbag system along the lines of "Open circuit in knee airbag squib". You'll need to power up the vehicle systems to play with the TPMS light.

[stewyinpagham]

The instrument pack doesn't want to come forward to easilly. So removed bonnet release mech and gained some access to the end 'box' presumably TPMS brain. Does this vaugly look like the correct 'unit' as I unplugged it ran the car across the car-park and no TPMS lamp lit or DTC's were thrown up?

[anchorman]

There are a couple of clasps holding the instrument panel. Don't be afraid to give it a good pull and it will make life a lot easier for you. The unit it down to the right when you can see through that hole.

[shcm]

I believe you are looking for an ECU with one 12 pin connector (2 rows of 6):

With wires in positions:

1 blue

3 purple

4 white

5 pink

9 white and black

10 green

plus it has a 3 pin connector for the antennae.

I can't tell from that picture. Is it all one connector? The position of the pink wire doesn't look right, it should be in position 5, but that one looks to be in an end orifice

Am I correct in thinking the TPMS light comes on at ignition as a system check, then goes out normally? With that connector out, does it come on at all at ignition?

[stewyinpagham]

SHCM , Anchs, others..

Its a race at lunch time with only 15mins to strip and 15 mins to rebuild! The connector I removed was a long singular connector and was the end gismo. The TPMS lamp displayed as normal during start-up. This was a box approx. 1/2" x 6" x 4".

I previously removed the screws from the instrument cluster and tugged but there was little movement, I was going to pull harder but the thought of having to splice a zillion wires back together before hitting the M27 didn't appeal. I seem to remember something about a 1hr delay in the lamp lighting but cant remember if that was sensors missing or box unplugged.

Is there a label or a part No. on the TPMS so I know it's the correct gismo as there appears to be a couple of gismo boxes in that location or hopefully it's the only unit with connectors described above.

This may be one for Saturday morning. At least I'll have wifeys motor to get me to Maplins for parts to bias the cct.

[shcm]

It *might* have a part number on it, possibly either:

89760-42010 or

89760-42011

Sounds to me like you didn't get the TPMS ECU, if the lamp was behaving normally. Careful, I think the 4WD ECU may be down there as well.

I only "speed read" through the other link you found, but, if I read it correctly, to be honest I'm still of the opinion you may only need one resistor.

They seemed to be using a fairly low-ish impedance potential divider in order to minimise the effects of the pullup resistor (which I don't know the value of) that is already there in the instrument pack.

If it were me, I'd measure the voltage at the ECU pin with the lamp off, then try disconnecting the lamp wire and replace with a known resistance say a 1K resistor (min) between the wire end and ground and measure the voltage again. From that I can work out the value of the existing pullup in the instrument pack and then, knowing what voltage should be at the pin to turn the lamp off, I can work out what value resistor really needs to be placed between the cable end and ground to keep the light off.

[MarsKy]

I seem to remember something about a 1hr delay in the lamp lighting but cant remember if that was sensors missing or box unplugged.

The way it seems to be is:

* If TPWS sensors are fitted to wheel, then on loss of tyre pressure you will get a warning light soon-ish, if not immediately.

* If TPWS sensors are not fitted, then you will get a warning light about an hour later to tell you that there is a problem with a sensor (continuous light) or problem with TPWS system (flashing light).

I've had my wheels without sensors fitted since before Christmas. The longest continuous run I've did is about 60 miles, otherwise it's been 30 miles here and there before stopping. The TPWS light has yet to come on.

[stewyinpagham]

My commute, all 12 miles of has often taken more than an hour. This lamp when it comes on will drive me round the twist!

Arrived at works early this morning. Instrument cluster now sat on my desk. Temping to take apart and block lamp out or remove whatever light source it is. With my luck, that will put another yet unseen 'the TPMS lamp is missing' lamp on!

[stewyinpagham]

Heres the results. All measured between Pink Pin #5 on instrument binicle and 0V. Oh, and the DVM is recently calibrated.

Engine and ign off 0.0V

Ign on, test cycle, 5.84V --TPMS lamp on for 3ish seconds--

Post test cycle, ign on, engine not running 0.13V --TPMS lamp extinguished--

Engine running, 0.15V --TPMS lamp extinguished--

let tyre down with enging running 7.0V --TPMS lamp lit--

To be continued....

[shcm]

Good Work!

Not quite what I expected but easier than I expected. It probably is just ground the instrument pack pin after all. A switch, switching the pack pin between either the existing lamp wire or ground, might be a nice solution. Easy "re-enable" if you want it.

Well done!

[local hero]

Good Work!

Not quite what I expected but easier than I expected. It probably is just ground the instrument pack pin after all. A switch, switching the pack pin between either the existing lamp wire or ground, might be a nice solution. Easy "re-enable" if you want it.

Well done!

Not quite sure if you have solved the problem, but if you have well done, needs posting on Rav 4 world as our American friends have also been seeking a solution, I believe ManxRav (Clare has connections) Stew

[stewyinpagham]

The results seem to follow that snipping the pink and grounding the wire from the instrument pack is the way to go. I will cut the wire over the weekend and bring a flying lead out under the dash to an easy accessable 0V. I'm sure that the car will have a good 1+ hrs continous run over the weekend and lets see it the lamp comes on in warning mode.

Now if anybody was to lend me a set of non TPMS rims for a day, I could finish the test 100% and go mud-plugging!

[MarsKy]

I just did a long run and the TPWS light came flashing on (as would be expected with no TPWS sensors fitted).

But I only noticed after I had parked up and was about to switch the engine off. The way my seating is setup, the steering wheel rim just about covers the light as I look down, so I never noticed it

On the way home, I had to peek to confirm it was on. I really don't notice it.

Anyway, I got home, parked up beside the storage box with my OEM wheels in it, and as expected, the TPWS finds the signals, and 10 seconds later, the TPWS light went off.

Edit: if Toyota had put in a beeper, then that would really have peeved me off.

Still, if Stewy gets his fix working, I'd probably go down the route of putting in a switch for fitting non-OEM wheels.

[stewyinpagham]

Here we go..

Snipped pink wire to Pin 5 on instrument pack. Ran a permanent 0v to a the chassis ground point behind lower OSF A panel trim. No lamp 'on' during ign. test cycle. Ran car for 1.25 hours continuous. No TPWS lamp. No other warning lamps or any other messages. I will leave this as is for a week and see if a longer run has any effect -timer?- and will then revert to TPMS normal operation. I've still not found the TPMS gismo box as my bottle is not up for playing with 'air-bags' but I don't seem to need to.

There was something comforting when conducting the tests when the TPMS the lamp came on immediately @19Psi...

Thanks for the tech. input SHCM. Now starts the debate, do I run 17" rims and sell the 18's.....?

Just realized... Connect the 'NEW' 0V cable from the chassis ground to the Pink from the instrument panel. Insulate old wire from TPMS.

Edited January 30, 2011 by stewyinpagham

[shcm]

Thanks for the tech. input SHCM.

Your welcome! Thanks for experimenting!

You could always put a simple change-over switch in, if you ever want to go back (probably not :D).

[wardude]

are you still running ok with no light coming on??? Why do you need to run that other wire though? Can you not just snip the pink wire and that will be job done? Sorry if its a daft question but im useless with wiring etc but im desperate to find a way of disabling the TPMS light

all best

shaun

[bluevortex]

I have a much easier solution to this problem. Its a piece of black insulation tape (roughly an inch) stuck directly over the flashing warning light! It works a treat and the ligh hasn't bothered me since November last year

Blue

[Jamesbelfast]

Bad news may be on the horizon.

VOSA the government body who oversee MOT testing are considering Tyre Pressure Monitoring Systems will a testable item in future MOT checks.:)

[wardude]

I hear thats only on new cars from when TPMS come into force as being compulsory fitted bits of kit. Knowing our luck though it will be only on new cars except Rav 4 T180s