Doors are automatically unlocking UPDATE : mystery SOLVED

[fourrunnerbill]

Hello,

I have this new problem with the doors automatically unlocking themselves. I'll be out of the vehicle and attempting to lock the doors using the lock button on the driver side. As soon as I press the button I hear all the locks engage but then immediately unlock again. The FOB also quit working also. This happened for a day then it disappeared the following day. While the door is closed I can use the key to lock the doors ok. I had the same situation about a year ago and it disappeared. The battery in the FOB is new. This time I had a 12V USB charger hooked up to the rear socked next to the 120V outlet. I unplugged it and later realized the problem went away. Could be just a coincidence.

Does anyone have any trouble shooting tips. I check the engine bay for rodent wire damage and didn't see anything.

2016 TE

Thanks

 

[N0RTHWEST]

I had something similar happen when my fob battery was low.

I changed the fob battery and disconnected the truck battery for 30 mins and reconnected. I haven't had an issue since. Hopefully yours doesn't persist.


edit: I'm glad you figured it out!!

 

[fourrunnerbill]

I'm going to try and reproduce this by plugging the USB charger back in. If it does happen I'm then going to put my FOB out of range, perhaps it was sending an unlock code out due to a faulty button.

 

[fourrunnerbill]

30 minutes later. I duplicated the problem by plugging the 12 USB port with 5V power bank back into the 12V socket. I removed it and the problem went away. This doesn't make much sense since the 12 socket should be unpowered when there's no key in the ignition so I don't see how this could make this symptom come and go. Only time will tell if this re occurs.

 

[thennen]

You could try plugging other things into that socket. Could be something wrong with the device (charger?) itself. If it occurs with other devices then maybe a problem with the truck.

 

[fourrunnerbill]

I wonder where the FOB RF antenna is located?

 

[Old Tanker]

30 minutes later. I duplicated the problem by plugging the 12 USB port with 5V power bank back into the 12V socket. I removed it and the problem went away. This doesn't make much sense since the 12 socket should be unpowered when there's no key in the ignition so I don't see how this could make this symptom come and go. Only time will tell if this re occurs.

By any chance, do you have an add-a-fuse plugged into the footwell fuse box? If so, doublecheck everything for plugs, correct orientation, etc.

 

[fourrunnerbill]

By any chance, do you have an add-a-fuse plugged into the footwell fuse box? If so, doublecheck everything for plugs, correct orientation, etc.

Hi I’m not sure what you mean by correct orientation. But yes I do have an add a fuse that powers some led grill lights and those have been working fine for 2years. These are of course unpowered when I try locking the doors so I’m not sure how this could be related.

 

[AZ4Running]

If this is plugged into the rear hatch power outlets it's possible there is some RF interference from that charging device making with keyless entry bug out. There is an antenna located on the floor of the trunk space very near those plugs.

 

[Old Tanker]

Hi I’m not sure what you mean by correct orientation. But yes I do have an add a fuse that powers some led grill lights and those have been working fine for 2years. These are of course unpowered when I try locking the doors so I’m not sure how this could be related.

I posted the comment because it is possible to install an add a fuse backwards, and it can lead to odd issues.

In my case, it resulted in taillight issues whenever the rear 12V socket was in use.

 

[fourrunnerbill]

I posted the comment because it is possible to install an add a fuse backwards, and it can lead to odd issues.

In my case, it resulted in taillight issues whenever the rear 12V socket was in use.

Ok. I used a completely unused spot on the fuse block but still a bit curious anyway.

Today I unplugged the power bank but leaving the cord plugged into the usb charger and it didn’t happen. So it does appear there’s some sort of RF interference coming from the power bank. I tried a different type of power bank and it also causes the problem. I moved the power bank to the 12v socket on the front console and problem also happens. Very strange. I don’t how these power banks could be radiating anything especially when there’s no 12v power on.

Maybe there’s a loose connection on the antenna.

 

[jp.vegas]

I posted the comment because it is possible to install an add a fuse backwards, and it can lead to odd issues.

In my case, it resulted in taillight issues whenever the rear 12V socket was in use.

Yeah, that's a frequently misunderstood fact. I doubt it's relevant here, as that's not something new introduced to the system, but it's completely possible to put the add a fuse in the wrong way and literally have no protection from the fuse you added if you're feeding the load off the hot side and not the load side of the fuse block. I always test them with a volt meter or test light to make sure I'm fusing my new circuit and not just running it without protection.

 

[fourrunnerbill]

Mystery solved

I had several USB power banks and only one caused this problem. A Zippo 2600mA hand warmer/power bank was injecting 3.7V on the micro USB charger input port. So some of this voltage was leaking through the 12V USB socket port. I have another hand warmer and several other 5V power banks and they do not have any voltage on the input as you would expect. I think this is a design flaw in the Zippo or it's defective although it functions as a hand warmer and is able to be used as a power bank just fine.

So it must be the ECU or other circuit (FOB RF receiver) in the 4runner does not like seeing any voltage being applied to the 12V.

A strange problem resolved.

 

[Saker]

Thanks for the update.
Strange indeed!

 

[Rocko9999]

I had several USB power banks and only one caused this problem. A Zippo 2600mA hand warmer/power bank was injecting 3.7V on the micro USB charger input port. So some of this voltage was leaking through the 12V USB socket port. I have another hand warmer and several other 5V power banks and they do not have any voltage on the input as you would expect. I think this is a design flaw in the Zippo or it's defective although it functions as a hand warmer and is able to be used as a power bank just fine.

So it must be the ECU or other circuit (FOB RF receiver) in the 4runner does not like seeing any voltage being applied to the 12V.

A strange problem resolved.

Thank you for the update. I had an issue on my daughters Altima where the cheap gas station USB charger would cause her TPMS lights to go on. The charger was emitting enough noise to interfere with the TPMS signal. Took a while to figure that out. Went to an Anker usb charger and problem solved.

 

[fourrunnerbill]

Thank you for the update. I had an issue on my daughters Altima where the cheap gas station USB charger would cause her TPMS lights to go on. The charger was emitting enough noise to interfere with the TPMS signal. Took a while to figure that out. Went to an Anker usb charger and problem solved.

Wasn’t it Scotty Kilmer who warned us about cheap gas station chargers. The same should apply to power banks. Your problem is an RF interference problem. My problem was back voltage from the hand warmer getting into the car 12v.

I have three different Anker power banks and never had any issues with them.

 

[UtahSooner]

I had several USB power banks and only one caused this problem. A Zippo 2600mA hand warmer/power bank was injecting 3.7V on the micro USB charger input port. So some of this voltage was leaking through the 12V USB socket port. I have another hand warmer and several other 5V power banks and they do not have any voltage on the input as you would expect. I think this is a design flaw in the Zippo or it's defective although it functions as a hand warmer and is able to be used as a power bank just fine.

So it must be the ECU or other circuit (FOB RF receiver) in the 4runner does not like seeing any voltage being applied to the 12V.

A strange problem resolved.

Glad you found the source. My guess is it was most likely an Electromagnetic Interference (EMI) issue as [MENTION=742490]Rocko9999[/MENTION] mentioned. Poorly designed electronics can radiate all sorts of noise and/or cause weird issues (ground loops, etc) that will affect a RF receiver (and other ECU/electronics). Also possible the device was applying an unexpected/out of spec load when plugged in and affecting the power to the RF receiver/controller in the vehicle.

There IS a reason cheap power supplies/cables/chargers/etc are less expensive… (tho sometimes even the “reputable” companies design and sell crappy products).

PS - I’m a field sales enginner for a company that, among other things, specializes in EMC/EMI Testing (Electromagnetic Compatibility/Electromagnetic Interference). It’s crazy how many companies do an absolutely terrible job of electronics design (and don’t actually design/test their products so they don’t interfere with other things in the general vicinity). Not to say that paying extra is always worth it, but many times the extra cost of a more expensive equivalent option is a function of the $$ spent on the engineering & testing to make sure the product works properly AND won’t interfere with other electronics.

Super frustrating to chase down weird ghosts in the system like you had - kudos for the troubleshooting to find the source!

 

[UtahSooner]

Wasn’t it Scotty Kilmer who warned us about cheap gas station chargers. The same should apply to power banks. Your problem is an RF interference problem. My problem was back voltage from the hand warmer getting into the car 12v.

I have three different Anker power banks and never had any issues with them.

Didn’t see this post on page 2 before making the previous post…

Either way, guessing the offending hand warmer is in the trash/recycling bin by now!

 

[Radio Flyer]

I see this a lot, last time I had a TPMS light come on, I unplugged things daily only to find out it was a bad sensor all along!

 

[TRD PANTHER]

I had a similar problem with a cheap, low watt USB cigarette charger adapter I used briefly for my iPhone. Everything worked fine for 3 weeks, then I could barely get the doors to lock/unlock. I had my battery replaced prior to this incident and couldn’t figure it out at first. Yanked it out and everything returned to normal.