Tire Pressure Light

Happened on my wife's 2008 Forester. She took it to the dealer and tire sensor was bad and cost about $200 for parts and labor. I think I would have put a piece of duct tape over the light.

I had a Camry rental last year when my Forester was in for repairs and they had pressures for all the tires on their screen. One warning light came on and I had to test them all to find which and add air. Pressure in tires varied up to 10 lbs but I did not care as it was a rental.

I hate these stupid things. Probably costs $100,000,000 in extra costs for each life saved.

How far have you driven since you added air? My Outback manual says you have to drive for a few minutes at 20 mph or above before the system will recheck the pressures.

Patty

Aha, so that's probably what it was. I just added the air, but I didn't drive it again, just thought that the extra air would automatically register. I did just drive it around the block and the light went away. So this tire pressure sensor must be circumferential rather than pressure-based?

Yousuf Khan

You're lucky and I should have mentioned that too but wife's sensor was definitely bad.

AFAIK a tire pressure sensor in one of these go/no-go systems sends out a periodic signal when the tire is spinning AND the pressure is low. That is the only way the little battery in the sensor can keep going for any length of time since if the car is parked or is moving with proper pressure then the transmitter just sits there doing nothing.

I have either a weird coincidence or some sort of interference with my TPM system in the 2008 Outback -- several times when I've driven down the interstate near the FBI center in West Virginia the pressure light has come on. The first few times I've stopped and checked each tire. Now if it happens I wait until I'm out of the vicinity and wait to see if the light goes out before taking any action.

I'm voting for interference...

Patty

The FBI is monitoring your TPM. :)

Yousuf Khan

Some car systems report the actual pressure in the tire.

Yeah, I was sweating bullets that that sensor would need replacing. My next decision would've been whether to ignore it or fix it.

Yousuf Khan

Would be nice if you could turn the damn thing off. I said I would probably have ignored it if it happened on my car but persistent light or knowing it was taped over would be annoying. $200 is an expensive fix and there are 4 sensors to worry about. Problem could also be with the receiving unit.

My brother used to work for Chevy dealers and they had a sensor problem that they could not cure on a car and the car was fine so they just disconnected the sensor.

I know. That is why I specified go/no-go system. I really don't know how the more advanced systems manage their battery life unless they report only infrequently when the tires or spinning or they might be smart enough to only report when a change in pressure occurs. Personally, I probably can't afford a car with enough smarts to report more than the basics.

During the winter, my TPM light is always on, as I don't have TPM monitors on my snow tires. During that time I just ignore it. But in the summer, I don't usually expect to see the light.

Yousuf Khan

The usual overabundance of oh-so-helpful electronics in a modern computer on wheels.

One option you have is to wait for the indicator to burn out or go for option two and pull the dash apart and tell thank you, but no thank you with an applicable wire cutter. Post on youtube to complement your rear wiper motor fix video.