Start/stop button and door handles not responding to smart key

2019 Limited (no mods other than fog lights installed 3 months ago)

I went to get in a few days ago and noticed the door handle didn’t respond to unlock when the key was in my pocket. Checked passenger door handle, same problem as driver side. Using the key fobs lock/unlock buttons still works to lock/unlock the vehicle from distance so I don’t think it’s the receiver in the hatch. Hopped in and the start button also wasn’t responding. No ACC, no ignition, button doesn’t work at all. Held the fob to the button for a few seconds and that does work still thankfully for ACC/starting the engine.

Same problem for both key fobs, neither work for proximity door handle/start stop button functions.

Tried:

Replaced batteries in both key fobs

Disconnected the car battery for the rest of the afternoon, reconnected later the evening

Checked car battery health - all good

Reset head unit to factory just incase (tho it’s the crappy early entune model no car settings controlled by it)

Brought it to the dealer to run diagnostic, all settings are fine. Techstream settings shows all correct still too.

No codes being thrown for any problems at all.

Dealer reset computer, problem still happening.

Key fobs reprogrammed to vehicle

Problem is still there, nothing has worked. Dealer wanted to pull the dash and try replacing the smart key/immobilizer module incase it was the issue but that’s insanely expensive. I also don’t really want to do this myself either, a lot of work for something pretty minor but still very annoying.

Have not heard/read anyone else having these specific symptoms for this problem, any ideas?

 

Its likely from corrosion?
Corolla S premium:
Proximity senses you there and turned the interior lights on. Fob would not unlock on driver's side but unlocks pass side.
Did some work around the battery, sprayed some corrosion prevention on a couple spots.
NOW IT WORKS

 

corrosion on the battery? Battery is spotless, clean, fairly new and tested for good health. All checked, no issues there.

 

I have turned off my proximity sensor before by adjusting the lock/unlock beep volume through the radio. There is a bug in the system.
It needs to be turned on again by Toyota, or a Carista app. You can a dongle from Amazon, then purchase a month subscription. It’s worth the purchase, you’ll be able to adjust all different customizable settings.
My push button start was not affected though. Only keyless entry and beeping when locking and unlocking went away.

 

The issues some are having with the remote fob no longer working to lock/unlock the vehicle after adjusting the beep volume are different than what OP is experiencing. One - his remotes work fine to lock/unlock doors, it's the door handle sensors that no longer lock/unlock the doors. The opposite of what you're describing. Two - his start/stop button doesn't work. Something is going on that isn't caused by the beep volume adjustment. I'm not sure you could even adjust the beep settings on a 2019. That started with the later models (2020+) that came with push button start. Limited have had push button start years before the other models

Good luck OP with the diagnosis and fix. This is a new one I've not heard of before.

 

Well, my door handle sensor and key fob dont unlock the drivers door again.

 

Yes thank you, you nailed it.

I already went through the settings with Toyota using techstream and all settings are correct.

The start/stop button isn’t something controlled by those settings anyway.

The 2019 head unit also doesn’t have the capability to even control any of those options, so Im not even able to mess with locking or beep volume options to screw anything up.

I appreciate the replies from everyone still though, thank you.

 

This is a first hearing of this with the 2010-2019 smart key system. Usually this is a 2020+ issue. First thing, check your fuses before anything else. There is a 7.5A SMART fuse in the engine bay fuse block. Make sure that is good. There’s also a 10A IGN fuse in the cabin fuse box. Visually inspect both, but if you have a multimeter test them with that. Sometimes what looks good actually is not.

The fact that the wireless lock function works, but the actual antennas (start button, door handles, front console, rear seat area, cargo area, hatch) are not picking up the key could be the ECU. I would place the key inside in those areas and see if it detects the key for starting. Does your rear hatch unlock at all with the key nearby?

 

Hey yes I should mention, I’ve tested the SMART fuse and all ECU variant fuses from both fuse boxes already since I first posted, both visually and multi meter. All those fuses are good.

Tried putting the key fob in various places all over inside and outside the cabin and no go. Also you’re right, the hatch is the same as the door handles, doesn’t unlock to proximity of the key fob. Basically any proximity smart key function doesn’t work. Only the lock/unlock buttons on the fob, and holding the fob to the start/stop button work.

I just tested any fuse labeled as any IGN variant at your suggestion and no problems, all tested good.

I might pull any DOOR related fuse and check those also later today to make sure.. though they should not have any relation to this issue since the start/stop button is affected too.

 

The door fuses won't do anything here. All the antenna wires are a direct feed to the smart key ECU, and it physically powers the touch door handles. It also powers the antenna within the start button. I think the fact that none of the peripheral sensors getting power means the ECU is the problem. Probably a bad capacitor on the circuit board. I would pull it and visually inspect.

 

I had the same thing happen , but to my wife’s Honda Pilot. It was the batteries, IN the key fob. There was enough power to send signal of the unlock buttons and such, but the wireless entry would not work, nor would the start/stop ignition button. On hers, if you hold the fob RIGHT NEXT to the start button and press start, it would start the vehicle. Basically, not enough power for the radio transmitter to work. Happened to both fobs around the same time. So replaced both batteries and both work fine now. It was a simple fix for me. Hopefully , simple for you as well! Good luck

 

…..aaaaand I skipped the one line where you said you replaced the batteries. Sorry.

 

I have a 2013 4runner Limited and I think it's had about 3 drivers door actuators. That said, I had an issue not long ago coming home at night. I would hit a bump and in a curve, lights blink on and off, everything go completely off and come back on. My negative battery cable was lose and I had to twist it on post and find a tight spot. I have a gel battery and I noticed corrosion around the terminal. I carry extra batteries for my FOB in the truck. It's hard to tell if you have a battery issue with the push button because you don't get the low battery starter clicks like using a key.

 

Anytime a battery is low enough to not engage the starter, it will click. Doesn't matter if you are physically twisting the key in the ignition, or have push to start. The push button only sends a signal to the key ECU which in turn tells the power management ECU to engage the starter. It will attempt to hold the starter relay closed until a set "start time" has elapsed without the engine starting, or you push the start button again. If a battery can't supply the required CCA, it will click.

 

Did you figure out a solution??
My Nephew's 2012 limited is doing exactly the same thing. I have a 2015 limited but mine is working like normal.
Just trying to help him out.

Thank you for your time.

 

Okay so we did find a solution to our issue where the remote still unlocks the doors but the proximity sensors when you approach and touch the 4runner doors does not work and the push start does not work unless you place the fob right on the push to start button. I found these on another forum and we did them twice first the double beep then the single beep at then end. Now everything works as it should again.

 

Nice find. Hopefully the OP will check back in and give that a try.