phatjoe

Hello,

So I took a look at a used 2006 911 with roughly 75k miles on it. It was very clean looking car, and drove well. Unfortunately, during the test drive the tpms sensor light went off.

The salesperson indicated (Toyota dealership), that he's familiar with Porsche's and that happens all the time. I think that's a bunch of bull, but thought I'd ask here first....

Is the tpms sensor light going off a common problem?

I know there's far greater things to be concerned about, but other than that, the car looked exceptionally clean. This will be first 911, so apologies for the silly question.

Thanks

DBJoe996

No, the TPMS light going off is not a common problem. That being said, it could be it is doing it's job and a tire pressure is low. Since you were just on a test drive I know you didn't check the tire pressure, and our low profile tires are a difficult read visually. And anyway, a TPM sensor can simply be replaced, although you have to figure out which one. Also for instance, on my other car which has TPMS, if it detects a low tire and the light goes on, then you find/fix the problem and have to do a TPMS reset. BTW I read somewhere the average life of a TPMS battery is about 7 years. You can get them replaced or rebuilt when doing a tire change. That's what I have done.

jhbrennan

Or...if these are the original TPMS sensors, batteries are probably depleted after 10 years - they usually last anywhere from 4 to 7 years.

JimmyB

2006 is a 997, right? The folks over there might have more insight

VFRMike

I work in the service department of a high-end car dealership in the San Diego area. What I can tell you is that the TPM system is the best, worst, invention ever. If it saves you a scary tire blowout, then it's all worth it. However every time we have a cold spell, we get a deluge of panicked phone calls about the "tire light being on".
If the tires were warm/hot the last time the pressure was set, and it was a hot day, and now it's a cold day, your light's gonna' come on (Boyle's Law of pressure/volume). A low-profile tire with minimal interior volume is going to be especially sensitive.
Also at 10yrs old, the "permanent" battery in each wheel sensor is probably at the end of its service life.

BIG smoke

Tire is low or the sensor battery is low or dead.
Check the tire pressure, add air, see if the light turns off.
"Common problem?". Sure is, when the tire is low.
Free air, or the cost of replacing all four sensors. A or B.

captainbaker

Only thing I could add is its $130ish online and $20 to swap at any reputable tire shop. The dealership has a gizmo that talks to the sensor and reads how many months of battery life it has. So if air doesnt fix it, $150 will.

BTW, you can read the pressure on the MDF display below the tach. If its below 31psi (?) its just low on air. But if you see a --, then the sensor has died.

door2416

If the rest of the car checks out use this as a negotiating ploy. I'd get a price from the Porsche dealer. My winter tires don't have sensors and I just learned to live with the tpms message.

semicycler

If the sensor in one of the wheels is bad (battery dead), then likely all sensors are on their way out. And if the sensors have dead batteries, then you need to check the four digit MMYY date code on the tires too. Too often the tires are just as old as the sensors. If the tires are 6+ years old they need to be replaced due to age.

So if the sensor batteries are shot and the tire age is really old, negotiate for a set of new rubber and sensors - about $1200 - $1500 or so installed on a pcar ($1K for the rubber, $200-500 for the four new sensors, installation & road force balancing).

jfort

I've been told that for a car tire each 10 degrees = 1 pound of pressure

Minok

It doesn't happen all the time, unless by all the time they mean someone driving around with the wrong or dead TPMS sensors in the tires (or no sensors at all).

The car with TPMS is going to want to see the sensors. If the wheels had the sensors removed or not installed, thats an issue. Get the sensors installed.

The TPMS sensors have batteries in them - that is how they presently send the pressure data to the receiving antennas in the car wheel wells. Older generations ran out like a normal battery. Improved designs only power up when the car is in motion so those last a lot longer. But, they all run out and need to be replaced at some point. When the first one goes, then at the next tire change just replace all 4 sensors. In the future, engineers may design sensors that can use the vibration of driving or the centrifugal forces to generate enough electricity to power the sensors, but we are not there yet.

MagnusB

I hate the things, way too expensive and run out of battery all the time ....

cpbmd

Agreed. I had to replace all the TPMS sensors on my 2007. They lasted 8 years.