javaman

Hey Guys/Gals,
I need some help please! Had a new Kenwood receiver installed today and on the way home, the "Service Tire Monitor" message came on, along with the tire symbol. I went into the DIC and to see which tire might be low. What I saw was "Front Tire Pressures XXX". Same thing for the rear. Checked the tires and all were properly filled. Next thing I know the rear gave me a reading. Front is still XXX. Ideas what might be causing this? Faulty TPMS? Is it possible the radio swap is causing this message?

Landru

TPMS sensors are powered by a battery, they're not 'faulty', battery dies requiring replacement.
The tell is XX reading when proper pressure's present.
Some last longer than others, some much longer, my '08 lasted over 8 years which is outside the average.
Not a big deal, shop for 4 new replacement TPMS modules for your tire shop to install and program. You're golden, set for years.
Use the Internet, like TPMS.com, Cultrag or whoever has best price which'll be much less than retail at tire outfits.

Now replacing TPMS usually requires tire come off, some use a trick whereby w/ tire off car, bending sidewall inwards at sensor location just enough to remove/replace units.
Chain tire shops won't use shortcuts and stick w/ the book recommending tire be removed, though.

Now it costs just as much to replace tires as it does TPMS inasfar as labor goes.
Sage owners anticipate this, have replacement sensors ready to go when tires are replaced, labor-wise it's cheaper.

Again remember modules have to be programmed to each wheel so system 'knows' what pressure belongs to which tire.
Shops selling tires have the instrument used for programming, hopefully they've the sense to know how to use it.

FWIW I snagged 4 Schrader (OEM) from eBay, vendor was a GM dealer and units 'fresh', not stale.
IIRC 4 ran $140 or so, including shipping.
Shop around, see what deal you can find.

I highly doubt it, TPMS has nothing to do w/ sound.
Was just a coincidence TPMS died around the time stereo was installed.

javaman

Thank you very much for your detailed response! Glad to know it’s more coincidence, than anything else with respect to the radio.
Did some “Googling”, resetting sensors not an option here? I know you said your ‘08 lasted 8 yrs. Thinking it’s time, as opposed to mileage that dictates replacement.. I have an ‘11 with 8000 mi. Even though mileage is low, car is 9yrs old.
I’ll start my search for sensors, in the meantime I assume it’s ok to drive?

Landru

No 'resetting', replacing is The Procedure for addressing dead TPMS.
One member opened a module since they're a sealed unit, he wanted to replace battery.
Sounded (to me) like a PITA vs a few bucks toward eliminating problem.

Yes TPMS longevity's about time, not miles and at 8 years you're overdue.
IIRC C5 TPMS batteries c/would recharge themselves w/ tire rotation, not so w/ C6 though.

Should be able to drive OK, tho' some members reported a Reduced Power condition.
IF computer 'thinks' tire is flat it'll set that code, limits to 55 MPH.
However you're not getting flagged on DIC, so drive as normal.

javaman

10-4! Thanks again!
Larry

Mad*Max

I find it odd that both fronts went at the same time...

javaman

I initially had “XXX” on all four wheels. Rear came back and gave me a reading. Found sensors on Tire Rack.com for $42.

Mad*Max

Which makes the sensors even less suspect, IMHO.

mn_vette

I find it odd that all the sensors started going out on the same day that you got the radio installed. The TPMS sensors transmit to an antenna which then goes back to one of the electronic control modules. I'm not sure which one, or where the antennas are, but if they some how messed with one of them it could cause an issue. If the control module is no where near the dash, then it could just be an odd coincidence. When I was at Discount Tire last they did a free re-something or other to make sure the sensor was bad before replacing it. Important note though. ESC will start kicking in when above 0.6G with the TPMS light on. Scared me first time that happened.

javaman

Oh boy....would pulling codes help here?

javaman

I do know the installer put the Sirius antenna behind the left tail light.

FatsWaller

One of the local club members has a high-end TPMS tool which he claims can query each TPMS sensor as to it's health and also program the sensors. Maybe find a shop with one of these to see if in fact the batteries are dead. I'm with @Mad*Max on this one. Why would all 4 sensors go dead at once? They usually die one at a time with some time span between them. If anything interferes with the signal between the sensors and the antenna, you can get the same XX reading.

javaman

Kind of lost here guys. Good and detailed information from all. Where do I start and where do I go from here? I don’t “turn my own wrench’s” but want to know the best way to go to fix/repair this issue.

FatsWaller

If it was me, I'd find a shop that has the correct tool to query the sensors and reprogram all of them. The problem is that the symptom that you are seeing is the same as if the sensor battery was dead, or also if the sensor was not programmed. If something is interfering with the signal, the usual result is that the LR sensor reports 'XX', and that's not what's happening here. The antenna system used to connect to the TPMS sensors is the same as for the key fobs (the RCDLR). With the right tool, the shop should be able to tell you if the TPMS batteries are good, and reprogramming successfully will tell you if they can communicate with the RCDLR. This would take at most 5 minutes to do - some shops might not charge you anything for it. If the batteries are found to be good, but the sensors can't be programmed with a professional tool, then this would tell you that something is interfering with the communication. Then I'd be suspicious of the installation of the new Kenwood.

1bdvet

Sounds like your TPS are done, here is a website you might want to checkout.

https://www.tpms.com/default.asp

Landru

Stay the course, start w/ the most likely.
Install new units, as I said you're due anyway.
IF problem persists, then tear dash apart inspecting wiring.
Checking codes periodically is always wise whenever anything strange begins, also.

Tearing anything apart is always the last step when known/common remedies fail to work.
Be advised if not tired/dead modules, issue's a weird one-off problem.

javaman

Thanks again Guys - this may or may not be strange. I just went into the garage and started the car. Message gone and all 4 sensors are working. I know the sensors don't recharge. Thinking sitting overnight with no movement allowed the batteries to provide a reading? By the way...the hatch was open just a bit for the battery tender. Don't think that had anything to do with the message being gone do you?

dr_gallup

I had a similar thing when I was on a road trip with my brother. He had his cell phone running Waze in the cup holder and and about 100 miles into the trip I started getting the tire pressure warnings and XX readings. We stopped and check all the tires and everything was fine. For the next couple of days the system worked without a glitch then on the drive home with the cell phone in the cup holder again it fritzed out. It's never happened again but we have not gone on another road trip. I think you have some kind on electromagnetic interference problem with the new radio.

javaman

I know that it seems more than just a coincidence that this happened after the radio install. That said, the radio is passive in the sense it does not send a signal out whereas Waze would.
make sense or am I missing something?

javaman

Just checked again and everything is normal. I did stop by the audio shop that did the install. Doesn’t think it’s the radio per se, thinking the interface might be causing an errant signal. He is checking with PAC.