Got a warning while driving car this morning: "TPC Inactive." Since then, the tire pressure reading has been off. I've tried to reset without success.

Anyone has any idea what this implies?
Is this the individual tire sensor acting up, or is it the central ECU brain acting up?

TIA

 

Doesnt sound too promising. Have the same thing as well for a month now, havent gotten around to checking it out but will do so this week I hope. Started out as one sensor acting up, then this. I wonder if the little batteries have exceeded their useful life, which is likely considering its been 5 years.
If so, will be replacing them with beru. No need to pay porsche brand.
Will report back once I have a clearer idea.

 

Hi Nick,

Just got off the phone with tire shop (very reputable shop that specializes in Porsche) and was told, to my relief, that it's most likely the battery going low. "TPC Inactive" **is** the alarm message when sensors run low on battery.

The charge is estimated to be $130 x 4 sensors, plus a small labor charge. He suggested I change all 4 since they all very likely are running out of life (mine is 2008 car).
He also said these sensors could be changed without re-mounting (and re-balancing) tires.

 

"He also said these sensors could be changed without re-mounting (and re-balancing) tires."

How can that be? I would love to know, so if/when you get the answer please share.

Cheers.

 

Ditto!

 

They make lithium battery ones now from Taiwan that last up to 8 years and cost about 50/sensor on Ebay. I know some on here are not too keen to putting on these seemingly cheap parts, but I prefer it since a whole set cost about the same as one Porsche sensor. Not to mention, I have OCD and can't stand the red exclamation point and yellow light of the flat tire. I am not, unlike my wife, dependent upon a light on the dash to tell me that I have a tire low on air. My life won't depend on this part should the Taiwanese people fail me. KIPOINT TPMS if anyone is interested. Your batteries are definately going dead and what the tire shop meant to say was that they break the bead of the tire on the rim to access the sensor. They can reuse the same valve and only replace the sensor body. If they are the same brand then they should be within a close enough tolerance to not warrant rebalancing the tire. They replace the sensor/retighten the valve and then reseal the bead. i.e. not having to remount the tire since they technically never removed it.

 

Can
Before you dish out the $$ for new sensors and remounting costs, try changing the season setting. i.e. if you're currently using summer, change to winter and vice versa. Then try the system reset/recalibration.

 

That may buy you a week or two, very much like shaking the batteries in the remote control....or perhaps that is just me. It's the beginning of the end....they are like Christmas lights once one goes out the TPC becomes inactive for all. My right rear was first to give trouble and would intermittently come back, but finally kicked the bucket and now the rest won't register. The system will automatically go into recalibration through normal driving so there is no need to switch between modes unless you just want to manually direct a recalibration attempt, in which case you can just select it from the menu.

 

I had a similar thing, the dealer reset it with the pwis. I would check that first, and no the sensors can't be change without dismounting the tires.

 

TT Surgeon, if you mean dismount as in completely remove the tire then that was not the case in my situation. I replaced all four personally and only broke the bead. Just leave the rim on the machine and change the sensor with bead compressed. If you reuse the same brand or similar and same valve then you may also still have a balanced wheel, but definitely recheck after sealing the bead back.

 

I think the PIWIS can also determine if the batteries are truly dead.

 

I gotcha, yes I could see doing it that way.

 

Resetting and changing summer winter modes doesnt help... Batteries are gone...

I recall in an search I had done maybe six eight months ago I had seen a post by someone pointing to a site that you could by tpms sensors at a discount. I cant seem to find it... It had "tpms" in the url...

However I did google it and you can get the beru OEM ones for less than the quoted $130. Here is the link, although I have no experience with them and no affiliation. I am sure that there could be vendors that sell them as well. Doesnt Tirerack do tpms as well?
http://www.bavarianx.com/product_p/4...turbo.r1.k.htm

Anyway, I will be diagnosing mine soon enough and will revert. I am in Europe so will be looking at my side of the pond.

 

As many stated, it's due to low battery life in the sensors.

Ironically, I recently noticed the light come on in my vehicle as well. I have a special tool designed to both check/reset TPMS sensors. It read "low" on all 4 sensors, which makes sense. Worth noting, two of the four still have enough life to work but I'll be changing all of them.

Let's get a group buy going on these...

 

Thanks everyone for your input. Resetting has not helped; I will go ahead and change the individual wheel sensor and will report the result. I am so busy that this might have to wait a few weeks however.

As for changing without having to re-mount and re-balance, the wheel shop was very specific about this being possible. I do not know how but it appears zippsub9 gave the explanation.