Key fob transmitter module and battery
Problem
A key fob for Toyota Altis year 2012 model worked intermittently.
Troubleshooting
The two CR1220 batteries were weak. Internal resistance was over 110 ohm.
Solution taken
The two old batteries were replaced with two spare new batteries.
The impact of not solving the problem
- The car door needs to be locked or unlocked manually.
- Weak batteries may leak and damage the remote control module.
Notes
- The key fob model in question happens to have no screw. It can be opened with prying and pulling by the left and right thumbnails.
- CR1220 is an IEC battery code and it gives the specification of the battery. C means lithium anode with manganese dioxide cathode. R means round coin cells. 12 means 12mm battery diameter. 20 means 2.0mm battery thickness.
- The battery brands that have been used before are Renata and Panasonic. Both are made in Indonesia.
Tools used
- Handheld battery impedance tester with 2-pin Kelvin pogo probes.
- (Optional) Slotted screwdriver to pry the key fob open.
This is problem-first learning. The knowledge was learnt because there was a problem to solve.