How does the TPMS work?

[MagicMan2000]

Can someone explain how the TPMS works?

I've gathered from other threads that not all rims/tire combinations will work because they do not contain the TPMS for Infiniti...? Is it a transmitter in the wheel or something? I thought TPMS worked by detecting rotation speed at the axle...meaning that it wouldn't matter what type of rim/tire combination you had as long at it was of identical diameter as the OEMs...

Thanks.

[dividedhighw]

The type in our EX is a sensor mounted inside the tire that transmits wirelessly to the control unit. The unit can only have 4 of these registered to it at any time and this registration must be done using Nissan's Consult II electronic tool.

If the control unit isn't able to get a sensor reading after some driven distance, it flashes the warning light. After another minute, the warning light stays on solid. Thereafter, every time you turn on the car, the light will flash for a minute then go on solid.

I know this because I went with 4 winter tires on different wheels but decided NOT to spend $600 for the sensors, plus another $200 each year to have them registered back and forth between summer and winter.

HTH,David

[kamiguy]

The type in our EX is a sensor mounted inside the tire that transmits wirelessly to the control unit. The unit can only have 4 of these registered to it at any time and this registration must be done using Nissan's Consult II electronic tool.

If the control unit isn't able to get a sensor reading after some driven distance, it flashes the warning light. After another minute, the warning light stays on solid. Thereafter, every time you turn on the car, the light will flash for a minute then go on solid.

I know this because I went with 4 winter tires on different wheels but decided not to spend $600 for the sensors, plus another $200 each year to have them registered back and forth between summer and winter.

HTH,David

Yes, It takes awhile before the sensors work after you switch over. I bought new rims and snow tires and had $ensor$ mounted. It took about 500k before the light started flashing. Kinda makes you wonder how safe this technology is if it takes that long to alert you that there is something amiss! It was time for my first service and I took my EX to the local Nissan dealer since the Infiniti dealer is 2 hours away. They reset my sensors for $28.. WHEW!!

[KJ911TT]

If I swap out my All-Seasons and put snow-tires on the same wheels each year, does that mean I have to pay to have the sensors reset each time?

- KJ

[jmess]

If I swap out my All-Seasons and put snow-tires on the same wheels each year, does that mean I have to pay to have the sensors reset each time?

- KJ

Nope as long as the wheels are installed on the same axle they came off of.

If you rotate tires/wheels the sensors should be registered again so the control module knows which axle they are on.

I think most TPMS systems have some best effort reconnection logic based on mileage. With my C6 if you installed wheels with no sensors you could drive 35 miles before the monitor would start complaining.

If the TPCM (control module) power on diags tests out good and it loses connection with all sensors, then you could assume (logic wise) there is some form of radio interference and keep trying for X miles.

Another note the sensors power down (reduce power) after X time with no rotation so the batteries live longer; I think the battery life span is something like 3-4 years. The sensors power up again (start transmitting or increase transmitting power) after the wheel start rotating and the TPCM is programmed to give the sensors time to powered up before complaining.

You can expect to replace your sensors when the batteries get weak. I think the TPMS warning light will come on when a sensor's battery gets low before a sensor battery is dead.

After living with TPMS and runflat tires on my C6 I was pleased that the EX didn't have runcraps/ridelikecrap tires. I passed on a 328i sportwagon because of runcrap tires, lack of HP, and features vs price.
Modified by jmess at 12:38 PM 12/10/2008

[KJ911TT]

Great Answer.

Thanks!

[BrokenTiller]

Is there a simple way to defeat the TPMS warning light? I switch to winter wheels every year on all of my cars and manually monitor the pressure. The yellow warning light is annoying for 4 months of the year.

[jmess]

Is there a simple way to defeat the TPMS warning light? I switch to winter wheels every year on all of my cars and manually monitor the pressure. The yellow warning light is annoying for 4 months of the year.

I would bet pulling a fuse would disable more than the TPM. If you could wire up an on/off switch for the TPM you would probably get some other form of warning light.

I am probably going to stick my sensor free snows on Friday and will get to see the warning light. I may go low tech and put tape over the light if that is an option.

With the C6, the active handling (stability control) was also tied to the tire pressure monitor and would reduce engine power and increase the active handling nanny factor if you had a flat tire (run flat/crap tire lost pressure). Having all 4 sensors missing didn't effect the active handling or reduce power when the light eventually came on.

[jmess]

Put my snow tires and wheels on last night. So when I left the house this morning there wasn't a warning light on. After driving 10 miles the tire pressure warning light started flashing. It flashed for about 5-10 seconds then went to a steady on. The light could easily be covered with a small piece of tape. The light isn't any brighter than the headlight on light.

It didn't snow last night and the temp was 37 this morning so I didn't get to test out how well the new Michelin X-ICE2 tires work. Highway ride and noise with the tires is acceptable though.

[Ogiku]

had my car parked in deep snow at -25 C . After pulling out after 5 hours the tire pressure light came on. so i jump out of the car and see that all the rims are full with ice and snow.so,could it be that the air is fine and just the sensors are frozen or reading wrong or can not transmit the signals?

[dividedhighw]

I would be very surprised if the TPMS sensors were affected by -25-deg C temperatures. Most likely, one of the tires is actually down a bit.

I had the experience where the car drove fine and all tires looked normal, but when the light came on, I checked and found that one tire was down 8 psi. (Closer inspection revealed a nail-like piece of metal, which I had removed and the tire repaired.)

My point is, functionally and visually, things can seem fine, but if I were you, I'd check it with a decent digital tire gauge.

HTH,David

[BrokenTiller]

Second winter with the EX is almost here and I have just changed over to my winter wheels with Blizzaks. The yellow TPMS warning light annoyed me last year for the first couple of months. Not going to let that happen this year so I did what I should have done last year: small piece of black electrical tape trimmed to a circle. A couple of tries positioning it in the dash window and now it's perfect! Invisible at night and barely able to see the tape in day light. Good alternative to spending $500 on the sensor valve stems.