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On at least five separate occasions, all during long road trips of more than an hour of non-stop driving, I've had my '15 TLX declare a failure of the tire pressure monitor system and display "--" for all tires. It has happened in both cold and warm weather. Eventually (~30 minutes or more) the pressure status returns for all four tires simultaneously. I asked for this to be looked at by the dealer yesterday, but as expected they came back with a "cannot reproduce" diagnosis, found no stored codes, and said they've heard not heard of any similar complaints from others.
In the few times that I have seen this, it was caused by radio interference.
Keep in mind that your TPMS uses ultra-high frequency (UHF) radio often around the 434 MHz range. Too often someone will have a pager, aftermarket radio, or some sort of industrial, scientific or medical piece of equipment that will also transmit near this frequency.
Your cell phone or blue tooth are not in the same bandwidth and will not cause interference with your TPMS.
It’s also a good idea when they reset your TPMS sensors to do this outside the shop where sensors from other vehicles will not interfere.
So, I would ask if you have changed the radio, have a pager, any other equipment that might broadcast in the UHF range?
Thanks for the feedback. I do not have any intentional radiators that utilize frequencies in that range. I do have a dashcam installed (Thinkware 7500) but I'd be hard pressed to believe that it is causing FCC part 15 interference in that range. Also, I can't relate that theory to the observation that it only happens on lengthy trips.
Many dashcams do interfere with the TPMS system. I would suggest that you try and remove it for a while and see if that solves the problem. Also appears where you route the dashcam power cord can also make a difference. Here is one dashcam manufacturer that had to come out with another style power cord along with instructions on how to route it because it was interfering with the TPMS. Again, it doesn't hurt to remove the dashcam and see what happens. dashcam causing TPMS interference
07-07-2017, 01:49 PM
