Wednesday, July 27, 2016

Even The Simple Repairs - Replacing TPMS Sensor Batteries

The Dash
    Tire Pressure Monitoring Systems (TPMS) are really important. So important  that they are now mandated on all new cars in the United States. A blow out or flat in a car is bad enough, but one on a heavy vehicle like an RV can be catastrophic! My RV only has 4 wheels, so I like to continually monitor their pressures and temperatures while traveling. A while back, I found a great deal on a TPMS system that was inexpensive, monitored and displayed all four wheels (and the spare tire) at the same time and was incredibly easy to install. Well, now that I've had it for a couple of years, I noticed some of the sensors didn't always report to the display properly. This is quite common, and usually signals the need for new batteries. Not that hard to do. No, really, it isn't.

The Battery Cage
First, you have to figure out what kind of batteries your sensors take. If they are INSIDE your tires, this is NOT a DIY job! But if they are the screw on to your valve stem versions, it's easy. Simply unscrew one of your sensors that needs a battery and then unscrew the plastic cap on the battery/sensor housing. There will be an o-ring or two there to keep out water. On all my sensors, they were broken and dry rotted. I did not see any evidence of water getting into the sensors, but I am going to replace the o-rings every year now. Under the cap, you will see a small "watch" style battery in a metal cage. It simply presses out of one side. I used a small piece of wood (not metal!) to lightly press on the battery side and slide it out of the cage. Once out, I could read the battery number. CR-1632.

Bulk Packaging
CR-1632 are 3V Lithium batteries. If you buy them from a big box store or a pharmacy they can be $5 EACH! No way was I spending that kind of money on a tiny battery. Looking online, I found on an auction site MANY MANY companies with 100% feedback in the tens of thousands, selling name brand CR-1632 batteries bulk packed with free shipping for A LOT less. I got 30 of them for only $3.99. At that price, I will be replacing all 5 of my sensors' batteries (and o-rings) each year when I de-winterize. As for o-rings -- They are VERY small and easy to lose (don't ask.) They are also very thin, so if they are not situated correctly in place, simply screwing the caps down will destroy them easily (again, don't ask.) I will be ordering about 50 of them to keep "in stock."

Once replaced, I set the tire pressures with a digital gauge and fired up the base unit which houses the display. All the tire sensors came up MUCH faster with fresh batteries and are working properly now. The whole job took about 45 minutes (the spare is underneath my rig so is tough to get to easily). Something this inexpensive and this easy that could save you from disaster is always worth doing!

Be Seeing You...Down The Road

Rich "The Wanderman"


  1. Rich
    Good article and reminder. I keep the maintenance schedule for our MH and toad on Outlook calendar and tasks on our laptop. The tire minder battery and o-ring change is due now, I have been delaying as we just had the brakes done and I wanted to recheck all of the sensors anyway to make sure the tech got them back on correctly and on the correct tires.
    We have the TireMinder system from Minder Research and they will replace the batteries free if you send in the old ones. Free O-rings too. Somehow I got a set ahead, so no I don't have to do without while they are in transit each way.
    O-rings are important. I ruined one sensor when the O=ring failed and it got wet and was toast. Live and learn.
    Keep up the good work.

    1. Monte,
      I destroyed a sensor a while back and (since I don't have a "mainstream" TPMS) it was REALLY hard to replace. But I managed to get one and a bunch of spare o-rings. I am now down to zero...time to find them in bulk.

      Thank you for your kind words....tinkering keeps me mostly sane. Let others know about these articles, who knows, maybe I can help someone out with a frustrating problem.

      Rich "The Wanderman"

  2. where do we get the o rings? Is there a industry number or size to order them?

    1. Anon,
      I know of no industry wide standard size, usually you can take on off and go match it at an autoparts or big box home store. if they are an odd size, the internet will be your friend after you measure them. Or just call the manufacturer for spares.

      Rich "The Wanderman"


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