Error in the manual I guess. Not the first minor error, and likely not the last. Probably an missed cut and paste artifact from some other Honda document.

I believe Honda keyfobs have used CR2032s for many years now.

 

If I recall these batteries are the same size except one is slightly thicker than the other so one has more capacity than the other but the same voltage which is the primary concern. There's probably enough flex in the bottom connection to allow either the 16 or 32. So if the thicker fits then it's fine. Honda probably should have put that in the manual but I suspect they prefer simple vs options for customers to reduce questions.

 

Same voltage (ie" same number of cells, just smaller), roughly the same diameter, but they are very different in terms of thickness.

Placing a 1620 where a 2032 belongs likely will result in poor battery contacts which could render the fob inactive or intermittant.

Placing a 2032 where a 1620 belongs likely will cause damage to the small clips that are generally used in all devices that hold this class of batteries in place.

NEVER substitute one size button battery for another.

 

The CR1620 is 2mm thick and the CR2032 is 3.2mm thick.

CR1620

5009LC

75–78

0.1

16 × 2.0

Used in automobile key remotes and early digital watches.

CR2032

5004LC

225 (CR) 190 (BR)

0.2 (CR) 0.03 (BR)

20 × 3.2

This is also the most common lithium cell. Commonly used on computer motherboards as nonvolatile BIOS memory and real-time clock (RTC) backup batteries.

 

The CR1620 is 2mm thick and the CR2032 is 3.2mm thick.

CR1620

5009LC

75–78

0.1

16 × 2.0

Used in automobile key remotes and early digital watches.

CR2032

5004LC

225 (CR) 190 (BR)

0.2 (CR) 0.03 (BR)

20 × 3.2

This is also the most common lithium cell. Commonly used on computer motherboards as nonvolatile BIOS memory and real-time clock (RTC) backup batteries.

Yup, the last two digits are the thickness, the first two are the diameter.

 

Bear in mind the manual says 1620 for the "Master Key with Remote Transmitter" , but 2032 for the Smart Entry Remote. Next page in the manual.

 

Thank you. That was my suspicion, but had not had time yet to go look it up to confirm.