Any updates as to whether a Kenwood head unit may be causing the TPMS interference? I don't mean to hijack this thread, but I was a couple of days away from ordering a Kenwood head unit to replace the aging OEM NAV unit. However, I have had enough of electrical problems and don't want another one. I had a Service Active Handling message come on intermittently (which disabled cruise control and some active handling features) for 10 years, with many visits to the dealer and probably $900 in attempted repairs before it got fixed.

Do you think I am likely to run into TPMS interference with a new Kenwood head unit? I just have no idea how prevalent this problem is. Thanks in advance.

 

I've had a Kenwood DNX9950 head unit for several years now with no TPMS interference. Last year I replace my OEM TPMS with aftermarket TPMS with no interference.
M...

 

Very helpful. Thank you so much.

 

Here's what I've noticed on mine. The Service TPMS light comes on almost exactly at 20 min into driving continuously. If I stop and shut the car off, same thing will happen at the next 20 min interval. Drove the car for a continuous 4 hours each way this weekend, and the first sensor to stop reading was the RR. After about another 20 min, it would switch to the LR not reading and the RR now reading. It would then switch back & forth between the rear sensors not reading at about 20 min intervals until about 2 hours in all 4 were displaying pressures but the warning light (triangle with the !) would stay illuminated for the remainder of the drive.

So I've deduced that 20 min seems to be a significant interval of time for these readings or lack of readings, and that once illuminated, the warning light does not turn off even if all 4 sensors are reading pressures. Other than that, I have no clue

 

Like you, 20 min is about the same for me. Noticed something yesterday which may or may not mean anything. Recently switched from an android phone (Samsung) over to the iPhone 12. Set up CarPlay yesterday and decided to go for a ride. Drove about 30mi, went to a store with my wife, got gas, drove locally and then headed home. (I mention the trip details because the car was pretty much running all the time). Total “running” time was probably close to 2hrs. As I neared the end of the trip, I commented to my wife how surprised I was that the TPMS light and message hadn’t come on. Well almost immediately it did!! This time though the dreaded xx was only on the left front sensor. In the past, XX would move from wheel to wheel, sometimes appearing on all 4, sometimes not. This time it didn’t move from the left front wheel.
Perhaps switching over to an iPhone solved the problem? Perhaps the XX now is actually due to a failing sensor? Car is an 2011 - tires have been changed but not sure if sensors are original. One thing going back to the start of the problem was the inability to program the sensors. Going to see if the LF message is gone today and if the sensors will now accept programming.

 

I tried turning off all Bluetooth on my drive this morning - phone (iPhone XR), Pioneer head unit. Like clock work as soon as it hit 20 min into the drive, the service TPMS warning popped up. This time all tires showed XX initially, then just LR & RF & then just LR for the remainder of the drive.

After the dyno session, the TPMS was on immediately and stayed on for the 30 min drive home with just the LR showing XX. Now the LR is the one that I was having a tough time getting to sync & Discount Tire couldn’t get it to sync either.

I finally got it to sync by closing the driver’s door, putting the car in accessory mode by leaning through the window & then starting at the LR. It activated immediately & then I was able to shut the car off, and start the process over beginning at the LF & working my way around.

Could the LR be causing the issues?

 

I think all these problems with the TPMS sensors has everything to do with dead batteries in the TPMS sensor

 

Sorry, don't agree with that. I get this problem happening as well and all I need to do is turn off the offending device and the sensor starts reporting again in about a minute, which I believe corresponds with the polling interval. It happened with the old sensors, and is happening with the new ones from the time they were installed. I checked the date codes on the new sensors before they were installed and they were only a few months old. The only difference from what is described in this thread is that I usually need to be driving for at least an hour before the error takes place. However 2 weeks ago, it happened almost as soon as my wife started using the Bluetooth earphones connected to her iPhone, about 20 minutes into the drive. Didn't happen again after the phone was switched off. That was the first time she used the earphones in the car, too.

 

Okie Dokie ...

 

I have a bone stock car with TPMS batteries dated 2018 and I have this issue about once or twice every year. The vehicle's battery is also new. Has always cleared itself with no intervention on my part, usually takes a day and a few trips to do so, but it is still annoying when stability gets cranked up as a result.

 

JABCAT, if you are suspicious of the LR sensor, then you can do a simple test to try to eliminate it from the mix. Reprogram the sensors in reverse order - start at the LR and proceed counter clockwise. This will switch the logical position of the sensors from front to rear. The LR will now be in the first programmed position, and will be reported as the LF. If you are still having the rear sensors reporting as 'xx' after doing this, then something is likely interfering with the communication. If the LF sensor reports 'xx', then I'd be suspicious of the sensor that's physically in the LR position.

 

Drove the car today for the 1st time in 4 weeks. I normally drive with the lights set on the parking light setting to illuminate my dark smoke tail lights & avoid any issue potentially being stopped. Today I decided to turn the headlights completely off and drove the car for an hour - no TPMS warning!

Now I had these same Morimoto head lights, tail lights & Oracle side markers in my GS without any issues with the TPMS, but I’m wondering if one is potentially causing the TPMS interference?

 

In my case, the sensor issues started after the radio went in but before the headlights. One thing I have recently noticed is that after switching from an Android phone to an iPhone it’s taking longer for the dreaded light and double X to come on. Going to leave the phone home and see if that makes a difference.

 

Mine also started after the radio swap. Only other mod I have is the M2W but I had that for months before I had issues.

I also added Sirius when I added the Kenwood. I’ve thought of pulling just that to see if it is interfering since I don’t have Sirius enabled in the car at the moment.

I’ve been out of town for a couple of weeks so I’ll take the GS to Ft Worth on Tuesday. Not sure I’ll have time to pull the Sirius unit before then.

 

Bought my C6 just about 2 months ago. When I picked it up the PO had just had 2 of the TPMS sensors replaced at a place in the Cincy suburbs, invoice said Bartec RS-1000 sensors. Well, on the drive home, about an hour in, TPMS light comes on and of course the other two are having issues. Got home, did some research and decided to buy the cheap <$10 tool to reset them. Did that and they were ok for a few weeks. The other two sensors started acting up again. Went to Discount Tire and they installed Continental 7001HPA sensors. Only had them for a couple of weeks, but so far no issues with 2 different brand sensors in there. I will be replacing my head unit in the next month, so I will see if that has any effect on anything. Just figured I would throw my experience out there.

 

Attachment 48333004

Trigger TPMS one at a time and get a battery reading from them, with the trigger tool on the side of tire at the valve stem.

Now start the car, put a tech II on the car, go to Body, then keyless entry, ten data, then walk around the car with the fob at each tire stem location, and see if the fob signal is dropping out from RFI in the car.

Hence tpms and fob atenna location are.
one in the glove box next to the slot,
A pair of them at the B Pillar on both sides of the car about the gas door location both sides.
One in back of the car center of the rear fender void are about the key location above the plate.

If the fob signal drops out at one of the tire stem locations, the disconnect anything after market to make sure it not causing the RFI.
Hence rear tail light LEDs, or even an after market sat antennas that may be mounted in the rear fender void.
In front of the car, same with LEDs, or even an after market GPS antenna that may be mounted above the radio in the dash.

Under the hood, could be as simple as after market spark plugs or after market spark plug wires that have less resistance than the oem units.

If you can weed out so there is no extra RFI noise, then it may be as simple as one of the fob antenna connectors corroded, one the antenna on the way out, or the RCDLR on the way out instead.

 

Very nice day here in Texas, 70 degrees no winds. I needed to take some Christmas stuff from Rockwall to my youngest in Ft Worth. TPMS messages on the way there and on the way back 20-30 minutes into the drive. I tried one day with phone on and back with phone off.

After lunch, with no urgent projects, I pulled the radio fuse and drove east on country roads. After and hour and 45 minutes of no warnings, I had to refuel. I’m pretty convinced with this test and the fact that my issues started right after I installed the Kenwood radio and Sirius receiver my RF leakage is tied to this. I tied the Sirius receiver into the factory antenna, but the connectors could be leaky. I have only had this issue show up on other than the left rear wheel once or twice. Maybe wrap those connector in Aluminum foil to see if it makes a difference? Otherwise I’ll try to isolate it to either the Kenwood or Sirius receiver.

 

Tinfoil, it not from just keeping the aliens from reading your thoughts.



On the sat antenna if up in the dash, since it only need to pull a signal from the top side, easy to create a dish type piece out of foil so it not directing any signals back over to the RCDLR besides it, and the fob slot antenna to the right side and down. Same with the after market GPS antenna for cup shape Faraday cage as well, since it only needs to be able to get a signal from the top side of it too. On the sat receiver and maybe even the radio, loose wrap all the way around it to Faraday cage it.
Same with the after market GPS antenna for cup shape Faraday cage as well, since it only needs to be able to get a signal from the top side of it too.
And don't forget about the radio after market adapter as well.

 

Dano523 - Thanks. That was kind of my line of thinking. I’m a retired SW guy but worked with RF Engineers much of my career. May be a few days until I get time to tinker.

 

Here is (hopefully) my final update on the TPMS situation with my ‘11 GS.

Wednesday afternoon, I pulled the console, removed the Sirius receiver (which was on the right side close to the RCDLR). I then took aluminum foil and wrapped all the RF connectors. Factory AM/FM and Sirius antenna. I also made a two side shield around the Kenwood GPS antenna ( on top of the center air vent) and wrapped the connections in the rear where I had tapped into the factory Sirius antenna to bring it to the front. When I reinstalled the Kenwood, I tried to get as much of the factory harness towards the drivers side.

Thursday, a sunny cool morning in Texas, I fired up the car and headed east. I drove an hour out and an hour back trying all combos of radio, Apple Car Play (wired and wireless) with no TPMS issues. So that’s about 4 hours of driving with either the fuse pulled or the connectors wrapped with no issues. I’m planning on replacing the console today and hoping for the best.

Thanks to all the input that helped me track this down.