b55er
2009 Mazda5 Sport AT
2009 Mazda5 Sport AT
170k, original owner, well maintained, live in California (no salt), typically garaged, no temperature extremes. Stock 17" wheels, Michelin Pilot Sport AS/3. Tire pressure is exactly 34 PSI cold on all 4. No aftermarket accessories anywhere on the car.
About 6 months ago I started getting a flashing TPMS light with no alert sound. Flashing TMPS indicates a failure somewhere in the system. Solid TPMS with alert sound indicates tire pressure low.
Using OBD Fusion with the Mazda5 add on, I was able to determine that "Wheel Unit #3 not responding". During driving I've gotten errors: U2618 (wheel unit #3), and U2616 (wheel unit #1)
As the car is pushing 8 years old with 170k on it, I thought that the likely scenario was that the batteries in the wheel sensors were crapping out. I brought the car to the Mazda dealer and requested all four sensors be replaced. They replaced the sensors and away I went. Two days later, I got the same error with the new sensors installed. I brought the car in and said they re-paired the sensors to the car.
About a month later, the TPMS light began flashing again. Connected my OBD Fusion again and got "Wheel Unit #2 not responding". I cleared the codes and drove off. About a hundred miles later, the light flashed again. This time it was "Wheel Unit #1 not responding". Too much of a coincidence that two new Mazda TPMS sensors would fail. Most of the time, after driving with the light flashing for 15-30 minutes or so, the light would spontaneously turn off and typically stay off for the remainder of the drive. The light would only come on intermittently after after 50-100 miles of driving. Not always. Not every time. But several times a month when I drive 50+ miles without shutting off the car.
I have several theories here.
1. I've read that cellphone chargers can cause RF interference with TPMS. I've always used a USB charger for my iPhone. No changes here. To rule out RF from the charger, I purchased a very high quality charger from Anker for my iPhone to see if this would help. Nope. I also pulled the charger from the socket after the light would go on to see if this would expedite the light turning off. It didn't. The sensors operate at 315 MHz. This is far away from cellular and Bluetooth. Again, I've always had an iPhone using Bluetooth since day one of purchasing the car in 2009. Nothing new here.
2. RF interference from another car. I'm not sure about this one, but the light goes on when on the highway at driving speed. If another car would cause interference, why would I have not seen this in almost 170k of driving? And so often now? And this would not only affect my car but others on the road. I haven't found any real-world evidence of this occurring from many web searches.
3. I did install Genuine Mazda tire valve caps (part# 0000-83-Z50) on the car. They are plastic, chrome plated, made by Mazda, and for TPMS. I can't see how this would attenuate RF as the signal itself is going though lots of sheet metal and plastic as is. I'll try reverting back to the stock silver factory valve caps for the next few hundred miles and see if the problem occurs.
4. Some type of failure of the TPMS receiver. It's my understanding that the receiver itself is part of the instrument guage cluster. Hopefully this isn't the case. Cluster seems to work well otherwise.
Thanks in advance on your thoughts on this one.
170k, original owner, well maintained, live in California (no salt), typically garaged, no temperature extremes. Stock 17" wheels, Michelin Pilot Sport AS/3. Tire pressure is exactly 34 PSI cold on all 4. No aftermarket accessories anywhere on the car.
About 6 months ago I started getting a flashing TPMS light with no alert sound. Flashing TMPS indicates a failure somewhere in the system. Solid TPMS with alert sound indicates tire pressure low.
Using OBD Fusion with the Mazda5 add on, I was able to determine that "Wheel Unit #3 not responding". During driving I've gotten errors: U2618 (wheel unit #3), and U2616 (wheel unit #1)
As the car is pushing 8 years old with 170k on it, I thought that the likely scenario was that the batteries in the wheel sensors were crapping out. I brought the car to the Mazda dealer and requested all four sensors be replaced. They replaced the sensors and away I went. Two days later, I got the same error with the new sensors installed. I brought the car in and said they re-paired the sensors to the car.
About a month later, the TPMS light began flashing again. Connected my OBD Fusion again and got "Wheel Unit #2 not responding". I cleared the codes and drove off. About a hundred miles later, the light flashed again. This time it was "Wheel Unit #1 not responding". Too much of a coincidence that two new Mazda TPMS sensors would fail. Most of the time, after driving with the light flashing for 15-30 minutes or so, the light would spontaneously turn off and typically stay off for the remainder of the drive. The light would only come on intermittently after after 50-100 miles of driving. Not always. Not every time. But several times a month when I drive 50+ miles without shutting off the car.
I have several theories here.
1. I've read that cellphone chargers can cause RF interference with TPMS. I've always used a USB charger for my iPhone. No changes here. To rule out RF from the charger, I purchased a very high quality charger from Anker for my iPhone to see if this would help. Nope. I also pulled the charger from the socket after the light would go on to see if this would expedite the light turning off. It didn't. The sensors operate at 315 MHz. This is far away from cellular and Bluetooth. Again, I've always had an iPhone using Bluetooth since day one of purchasing the car in 2009. Nothing new here.
2. RF interference from another car. I'm not sure about this one, but the light goes on when on the highway at driving speed. If another car would cause interference, why would I have not seen this in almost 170k of driving? And so often now? And this would not only affect my car but others on the road. I haven't found any real-world evidence of this occurring from many web searches.
3. I did install Genuine Mazda tire valve caps (part# 0000-83-Z50) on the car. They are plastic, chrome plated, made by Mazda, and for TPMS. I can't see how this would attenuate RF as the signal itself is going though lots of sheet metal and plastic as is. I'll try reverting back to the stock silver factory valve caps for the next few hundred miles and see if the problem occurs.
4. Some type of failure of the TPMS receiver. It's my understanding that the receiver itself is part of the instrument guage cluster. Hopefully this isn't the case. Cluster seems to work well otherwise.
Thanks in advance on your thoughts on this one.
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