Problem with Key Remote Lock and Unlock 2016 4Runner

[Lexington]

Hi All

Recently my key remote lock and unlock feature hasn’t been working properly. Sometimes it works and sometimes it doesn’t. I’ve replaced the batteries in both keys and tested both keys for a signal and they work. Even after this the problem still persist with both keys. So I can safely say the keys aren’t the problem. Grok says the most likely cause is the keyless entry receiver is going bad and that it’s located in the rear cargo area — behind quarter panels, near the rear wheel well but it didn’t specify which wheel well. Does anyone know where exactly this receiver is located? Is it an easy DYI project? I tried looking for a video on YouTube but didn’t find anything. Any help will be appreciated.

Thanks

 

[fourrunnerbill]

I had a problem similar to this and I discovered it was due to a zippo power bank that was left plugged into the 12V socket. This power bank was back feeding a small amount of voltage back into the electrical system. I have several power banks and the zippo is the only one that did this.

 

[Lexington]

I had a problem similar to this and I discovered it was due to a zippo power bank that was left plugged into the 12V socket. This power bank was back feeding a small amount of voltage back into the electrical system. I have several power banks and the zippo is the only one that did this.

I don’t have a power bank so I don’t think that’s the problem but I appreciate your comment.

 

[osugsxr]

Hi All

Recently my key remote lock and unlock feature hasn’t been working properly. Sometimes it works and sometimes it doesn’t. I’ve replaced the batteries in both keys and tested both keys for a signal and they work. Even after this the problem still persist with both keys. So I can safely say the keys aren’t the problem. Grok says the most likely cause is the keyless entry receiver is going bad and that it’s located in the rear cargo area — behind quarter panels, near the rear wheel well but it didn’t specify which wheel well. Does anyone know where exactly this receiver is located? Is it an easy DYI project? I tried looking for a video on YouTube but didn’t find anything. Any help will be appreciated.

Thanks

read this

Keyless Entry Stopped Working

 

[Lexington]

Thanks for this link. It fixed my problem!!! I had Duracell in my keys and switched to Energizers and it worked. I’ve tested it multiple times through out the day and it has worked perfectly.

So I was curious as to why Duracell battery were causing problems but not others. I found a very interesting answer.

I asked Grok this question and this was Grok’s reply.

Why Duracell (and some other brands) cause issues while others don’t
Many premium batteries like certain Duracell button cells (e.g., CR2032, CR2016, CR1632 — common in 4Runners) now include a bitterant coating (often Bitrex) for child safety. This is a thin, bitter-tasting layer meant to deter kids from swallowing them. 
In key fobs and similar low-power devices:
• The coating (usually on the negative/flat side) can act as a very thin insulator.
• It prevents reliable electrical contact between the battery and the fob’s metal contacts, especially under light spring pressure.
• This leads to intermittent failures — exactly as you described: works sometimes, gets worse over time, range drops, etc.
• Vibration, temperature changes, or slight misalignment make it unreliable.
Other brands (Energizer, Panasonic, or generic/high-quality no-name) often lack this coating or apply it differently, so they make solid contact right away. 
Some owners fix Duracell batteries by:
• Wiping the contact surfaces thoroughly with isopropyl alcohol (rubbing alcohol) to remove the coating.
• Or very lightly sanding/buffing the negative side (carefully, to avoid damaging the battery).
Duracell has updated some lines (e.g., for AirTags compatibility) to move the coating or improve it, but older stock or certain batches still cause problems in tight spaces like key fobs.

 

[hudsonwilson12]

Also have this issue—admittedly, I've had it for about 2-3 years HA. Don't have a fix for you, but I did a bit of research a while ago, and I remember watching a few videos on a guy who replaced the actuator in the door?? I'm sure I'll get to it eventually