Can you replace the battery in a TPMS sensor?
It has always bugged me a little that we’re supposed to throw out TPMS sensors when the battery goes dead and the TPMS light comes on. Why not just make it a compartment that opens and use a commercially available battery?
Toyota TPMS sensor battery replacement
I decided to try replacing the TPMS battery on a 2010 Corolla as a test case. The battery is covered with potting compound, just like every TPMS sensor, but it’s fairly soft and flaky compared to some potting compound.
The potting compound is likely the reason most TPMS sensors don’t have replaceable batteries. Potting compound prevents vibration, strain, and shock from damaging electronics. The sensor lives in a wheel that spins fast and rolls over potholes. The potting compound is what keeps it from failing quickly. These sensors are actually surprisingly reliable. The battery is really the only failure I’ve seen.
Remove the TPMS sensor battery
A little digging with a screwdriver and brushing with a wire brush the the battery is exposed. The battery is spot welded to the straps coming from the circuit board. Generally this type of strap can be removed intact with a bit of effort. Leverage with a pocket screwdriver or needle nose pliers generally works fairly well for me.
I removed the TPMS battery without any damage to the circuit board or straps. Hooray!
Toyota (or Pacific) used a watch style battery for the sensor. There are no markings so I’m not sure it would be easy to find a place to buy one. If I were serious about, I’d do the research. The TPMS battery looks a bit like a CR2032, so I’ll use that battery.
Spot welding the battery tabs
It’s possible to connect the battery with some solder, flux, and skill, but it’s a whole lot easier and more reliable to spot weld the battery straps to the battery.
TPMS sensor works after battery replacement!
Success! The dead TPMS sensor has come back to life!
Now, I could order some potting compound and finish the repair, but I’m not going to. Here’s why:
- You can get a cheap TPMS sensor from Amazon for $30
- You can get a good TPMS sensor for about $60
- It took me about 45 minute to do this repair ($111)
- This will never be as reliable as a new sensor
- The battery is smaller and won’t last as long
I’m sure I could get my time down after doing a few units, but I doubt I’d be able to match the price point of a good quality sensor, much less a cheap sensor. Also, we’ve never been about price only. We want to provide value. This repair would be both more expensive and be less reliable. That’s not good value.
That said, I do like fixing things. When I get done working at the end of the day I often find other things to fix or spend time learning about how to fix or make things. If that’s you too, maybe you’ll want to put a new set of batteries in your own TPMS sensors. It might be a fun little project.
However, if you’d like us to fix you TPMS problem, we going to insist on new good quality aftermarket sensors, or original equipment sensors from Toyota, Honda, Subaru, or Mazda.
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