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Rider
'17 Springfield, '20 Chieftain
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Discussion Starter · #1 ·
Does anyone know where the TPMS signal is picked up by the VCM. Is there a receiver or antenna on the frame somewhere. My 2017 Springfield front TPMS is becoming intermittent once again. It was replaced under warranty at around 13000 miles and now I have a little over 20000 and it is acting up again. There are quite a few threads about TPMS failure to read issues and most of those are for the front TPMS sensor. Before my first one was replaced under warranty, the dealer reset it and indicated it was fine. Although, as it continued to degrade like my current one, it took longer (more driven miles) before it started to read. When new, it would respond within a block or two. Now it is taking about 8-10 miles of travel before it is read. My belief is that the battery in the sensor may be weakening. But, it should still be read if the receiver / antenna were closer to the tire. I have looked at the Service Manual and the only antenna I see in the schematics is the one used for the FOB / Security system. Is this same antenna possibly serving to roles? If is is used for the TPMS signal as well, it might explain why there are more failures with the front sensor than the rear since it is located closer to the rear tire. Any ideas?
 

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One of the true experts may have to answer this question, but I am somewhat sure motorcycles like most cars use a "Direct TPMS" system, which means the antennae is an internal part of the sensor itself inside the wheel. "Indirect TPMS" monitors it by wheel speed and several other factors, but there is nothing attached inside or outside the rim from my understanding.

So there is not external antenna.
 

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Rider
'17 Springfield, '20 Chieftain
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1,498 Posts
Discussion Starter · #3 ·
The TPMS is just a pressure transmitter that is "activated" by wheel motion. It's a wireless transmission from the TPMS pressure sensor. The signal then has to picked up / received, and then processed by the VCM before it is digitally displayed. My question is where is this signal being received external to the VCM?
 

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I recently had a question about an unexplained gizmo I found atop the battery cover just under the VCM. After reading your post, I asked my local service rep about the TPMS antenna and he described that same item. It's the (approx) 1" X 4" device pictured here. It is also used for the FOB.

603269
 
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Rider
'17 Springfield, '20 Chieftain
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1,498 Posts
Discussion Starter · #5 ·
My job is a little over 10 miles from the house. I usually ride to work everyday unless the weather is total crap, and ride to lunch. With Covid and restaurant situation I have been riding home for lunch. About a month ago, my front sensor started acting up. When new, both of my sensors would report the pressure within a couple of blocks. However, as my front sensor started to fail last year and again this past month, it would usually take 5-8 miles before I got a front pressure reading, and infrequently I could make it the full distance without a reading. Last night after I started this thread, I repositioned the antenna that is pictured above (schematic refers to it as used for the FOB and security system). It is only stuck down with double faced tape. I didn't want to cut my harness up, and there was only about 4-5 inches of wire slack. But, it did allow me to remove it from under the ECU / VCM connectors, and away from the battery and run it along the wiring harness running vertical behind the rear cylinder. After doing so, I went for a ride and within a couple of blocks I got a reading which hasn't been happening for weeks. But, instead of posting my results, I wanted to see what it did today. To work, out for lunch, back to work, and then back home it took many miles of travel before it started to work. So it must have been a fluke last night. Anyhow, those are my findings so far.
 

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After about three years, the rear TPMS sensor on my 16 RM would act up. It was slow to show a reading when starting off. Then, without explanation, would stop working later during the ride. On some days it was fine, others not so much. So, I told my wife the RM was irreparably broken and bought a Challenger.
 

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Rider
'17 Springfield, '20 Chieftain
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1,498 Posts
Discussion Starter · #7 ·
After about three years, the rear TPMS sensor on my 16 RM would act up. It was slow to show a reading when starting off. Then, without explanation, would stop working later during the ride. On some days it was fine, others not so much. So, I told my wife the RM was irreparably broken and bought a Challenger.
LOL. Now that’s a good way to fix it.
 
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