How I fixed my problems with key fobs

[stickerbush]

A few months ago I started experiencing issues with both of the key fobs for my 2020 GT. There were intermittent issues with the fobs not being recognized, situations where I'd have to hold the fob close the start button, doors wouldn't lock or unlock remotely, etc. Symptoms that I thought were the hallmark of a weak fob battery so I put new batteries in the fobs. Initially, the battery replacement seemed to help some but there were still intermittent issues that got worse as time progressed.

About a week ago I decided to replace the batteries again but this time I used name brand (Duracel) batteries that I purchased at a hardware store. The previous replacement batteries were made by Max Force. With the Duracel batteries the fobs worked as they did when the car was new. Fingers crossed but so far I have experienced no fob issues with the new Duracel batteries.

 

[Conrad 16.5]

Max Force batteries? Must be a subsidiary of SuperVolt.

This is the exact reason that I use my multimeter to check the status of new batteries when I install them. New batteries can be bad right out of the package.

True, the DMM doesn't place a load on the batteries but, 'normally' if the reading is at or VERY near the rated voltage of the battery, the battery is questionable at best.

 

[cxha]

...
This is the exact reason that I use my multimeter to check the status of new batteries when I install them. New batteries can be bad right out of the package...

By far the most common issue when users post problems with so-called new batteries, sometimes trying more than one not realizing that they purchased a whole batch of duds.

 

[Freedom55]

Max Force batteries? Must be a subsidiary of SuperVolt.

This is the exact reason that I use my multimeter to check the status of new batteries when I install them. New batteries can be bad right out of the package.

True, the DMM doesn't place a load on the batteries but, 'normally' if the reading is at or VERY near the rated voltage of the battery, the battery is questionable at best.

Right on! A good fresh battery should show about 3.3V. I know it sounds silly when a 3V battery is questionable if it reads 3V on the DMM but that's how the fob work. It was the same on my previous Nissan. At 3V the batteries could still be good for other uses such as decorative LED candles. I've had good luck with dollar store batteries that cost less than $1.50 for a pack of 3! They lasted almost as long as the OEM, can't complain.

 

[stickerbush]

Max Force batteries? Must be a subsidiary of SuperVolt.

This is the exact reason that I use my multimeter to check the status of new batteries when I install them. New batteries can be bad right out of the package.

True, the DMM doesn't place a load on the batteries but, 'normally' if the reading is at or VERY near the rated voltage of the battery, the battery is questionable at best.

The batteries I removed measured 3.01 and 3.09 volts with the DMM. Measured with no load.

 

[Freedom55]

The batteries I removed measured 3.01 and 3.09 volts with the DMM. Measured with no load.

Just for the heck of it, I've just opened my spare pack of batteries I bought a year ago and I measured 3.32V on my DMM. Our Canadian members may know Dollarama the store I bought the batteries from; they are Sunbeam $1.25 for a pack of 3. In US $ this is less than $1 for 3! I always keep CR2032 spares not just for my CX-5 but also for the garage door opener and LED candles so the lady of house can count on me to replace failed batteries...That being said, apparently Energizer are the longest lasting CR2032 but they don't come cheap especially if you buy one or two at a time.

 

[Conrad 16.5]

The batteries I removed measured 3.01 and 3.09 volts with the DMM. Measured with no load.

There you go.

" 'normally' if the reading is at or VERY near the rated voltage of the battery, the battery is questionable at best."

Those batteries are done.

 

[Conrad 16.5]

Right on! A good fresh battery should show about 3.3V. I know it sounds silly when a 3V battery is questionable if it reads 3V on the DMM but that's how the fob work. It was the same on my previous Nissan. At 3V the batteries could still be good for other uses such as decorative LED candles. I've had good luck with dollar store batteries that cost less than $1.50 for a pack of 3! They lasted almost as long as the OEM, can't complain.

It's not just fobs.

The sensors on my home's alarm system use the same batteries as our fobs. I get an alert from the base station when the batteries start to get low. When I check em with my DMM, they're just above 3vdc. The system doesn't like the voltage that low either.

 

[stickerbush]

It's not just fobs.

The sensors on my home's alarm system use the same batteries as our fobs. I get an alert from the base station when the batteries start to get low. When I check em with my DMM, they're just above 3vdc. The system doesn't like the voltage that low either.

I had similar experience with home alarm system sensors.

 

[stickerbush]

There you go.

" 'normally' if the reading is at or VERY near the rated voltage of the battery, the battery is questionable at best."

Those batteries are done.

Yeah, they were done when brand new. Cheap crappy product.

Both the Max Force and Duracells read 3.3V right out of the package. The Duracells work great, the Max Force work poorly if at all.

 

[chickdr]

Yeah, they were done when brand new. Cheap crappy product.

Both the Max Force and Duracells read 3.3V right out of the package. The Duracells work great, the Max Force work poorly if at all.

That makes no sense. If they have the same voltage, why wouldn't they work equally well?

 

[cz5gt]

thats the difference between good and not so good batteries under load. One may drop to 3v while the other keeps at 3.2v when sending signal (under load) and mazda key detection system triggers an alarm. Same with car batteries.
You may have 12.5V but when the starter kicks in it could drop much lower and no start. All new cars in the last decade have a minimum V pre-set as a failsafe for all the electronics. Cars are literally big computers in the past decade or two.

 

[chickdr]

OK so the other battery "appears" to be the same at rest, but isn't under load.

 

[7eregrine]

I bought batteries on Amazon. Constant issues. Got some new Duracell from the drugstore...that was 2 years ago.

 

[chickdr]

I bought cheap ones myself. No issues.