Central locking intermittent fault

[Lizzie]

Hi there, the central locking on my 2005 Corolla hatch has been playing up on and off for a couple of years, but it is the worst it's been now.

I have recently replaced the battery in the remote again.  It does feel a bit 'spongey' and I was told it isn't as responsive anymore when was serviced a couple of years ago (and that the Toyota genuine remote is no longer available).

When it is playing up like now, I can't lock the doors at all using the remote but the lights all flash inside and out, and I can hear the clicking sound in the doors.  I can generally unlock the car with the remote though.

The other change is that I can't lock the doors with the lock button to the right of the steering wheel.  At the moment I am having to resort to manually locking all 5 doors and remember to lock myself in for security if driving through a rough area.

I am pretty confused about the source of the problem - remote, central locking system, fuse? but if I can solve it myself with some help from anyone here who has had the same problem I'd be very appreciative.   Thanks heaps!!

[campbeam]

I am not saying that this is the solution but you could try the steps in the following link.

https://www.baierltoyota.com/blog/how-to-turn-off-toyota-corolla-automatic-locks/

Experimenting by doing similar steps solved my issue when the alarm was sounding a few minutes after locking the doors on my Aurion. I also had the window down just in case I locked myself in the car and the doors would not unlock.

 

[Tony Prodigy]

16 hours ago, Lizzie said:

I have recently replaced the battery in the remote again.  It does feel a bit 'spongey' and I was told it isn't as responsive anymore when was serviced a couple of years ago (and that the Toyota genuine remote is no longer available).

Dirt and grime can build up inside the keyfob mainly on the contacts. If you know how to pull it apart, I'd suggest trying to clean the contacts on the PCB and the corresponding rubber pad first so you know the key fob is free from any defects. . I always have isopropyl alcohol in the house as it is very handy. Get yourself some and follow the procedure in this video. Hopefully this will cure any issue with the remote. Then you can move to the next stage of troubleshooting if the issue still persists.

You can also get aftermarket replacement fobs so don't worry about that side of things either.

16 hours ago, Lizzie said:

When it is playing up like now, I can't lock the doors at all using the remote but the lights all flash inside and out, and I can hear the clicking sound in the doors.  I can generally unlock the car with the remote though.

This is where it gets interesting. It seems that the central locking is receiving a signal by virtue of the lights flashing and the "clicking" of the door mechs. So the way I understand it is, the door mechs will click when trying to lock but not actually engage ?  I suspect then there is an issue with the master switch or the central locking control module or wiring. The fuse has nothing to do with it at this stage. The module works by receiving the RF signal and then depending on which button you press it will send 12v to the door locks to lock and then to unlock the doors the polarity will reverse. Looks like there could be an interruption in the "lock" signal path. 
It will unlock electrically but won't lock electrically.  If the issue moves past the key fob to more electrical diagnosis, then you may need the services of a qualified auto electrician to measure the incoming voltage to the door lock solenoids. There could be damage to some part of the wiring loom or corrosion in a connector. Has the car had any collision repair recently ?
Start with the basics and then progress from there. Do you have someone around who's handy with a multimeter who could take a few measurements ?

 

[Novicebutnice]

20 hours ago, Lizzie said:

Hi there, the central locking on my 2005 Corolla hatch has been playing up on and off for a couple of years, but it is the worst it's been now.

I have recently replaced the battery in the remote again.  It does feel a bit 'spongey' and I was told it isn't as responsive anymore when was serviced a couple of years ago (and that the Toyota genuine remote is no longer available).

When it is playing up like now, I can't lock the doors at all using the remote but the lights all flash inside and out, and I can hear the clicking sound in the doors.  I can generally unlock the car with the remote though.

The other change is that I can't lock the doors with the lock button to the right of the steering wheel.  At the moment I am having to resort to manually locking all 5 doors and remember to lock myself in for security if driving through a rough area.

I am pretty confused about the source of the problem - remote, central locking system, fuse? but if I can solve it myself with some help from anyone here who has had the same problem I'd be very appreciative.   Thanks heaps!!

Based on information that the problem doesn't seem to be only with the remote, but also the button in the car,

I would say that the door lock actuators are more than likely becoming weak/ failing, or in need or lubrication (no idea if that is even possible)

My 2005 Corolla sedan developed the same issue (it started off with hearing a strange noise when locking the doors intermittently), followed by the door not locking/unlocking electronically (originally rear left, then after a few years the drivers door) 

I removed the door trim (after it stopped locking/unlocking electronically) and took one look at what was needed to access the door lock actuator assembly, and then put the door trim back on and decided to just live with it (I traded the car in a couple years ago).

[Tony Prodigy]

11 minutes ago, Novicebutnice said:

Based on information that the problem doesn't seem to be only with the remote, but also the button in the car,

Yes. I recommended a clean up of the remote contact patches inside the fob. It's also possible the master switch could dicky too, but it's better to start with the simple things first and then progress to the next phase of checks.

13 minutes ago, Novicebutnice said:

I would say that the door lock actuators are more than likely becoming weak/ failing, or in need or lubrication (no idea if that is even possible

Anything is possible, yes, but it would have to be a big coincidence that all four locks don't want to open at the same time. Something tells me it's more likely to be an electrical gremlin not mechanical. The doors unlock after being locked, so i would safely assume the linkages are ok.

[Novicebutnice]

2 minutes ago, Tony Prodigy said:

Yes. I recommended a clean up of the remote contact patches inside the fob. It's also possible the master switch could dicky too, but it's better to start with the simple things first and then progress to the next phase of checks.

Anything is possible, yes, but it would have to be a big coincidence that all four locks don't want to open at the same time. Something tells me it's more likely to be an electrical gremlin not mechanical. The doors unlock after being locked, so i would safely assume the linkages are ok.

I hate electrical gremlins...

 

[Tony Prodigy]

57 minutes ago, Novicebutnice said:

I hate electrical gremlins...

 

Haha, yeah me too. It requires a little patience, the right tools and some free time. I recently purchased some back probes as an addition to my multimeter to be able to probe those modern connectors as they have these rubber gasket seals where the wires enter the sockets. Back probes are very fine needle like instruments to be able to slide into the rubber seal and make contact with the conductor inside the socket. Normal meter probes are too tick and virtually impossible to penetrate. Only good for general testing and those older molex plugs where you can actually see the metal connector through the sides. 

If you have access to a vehicle schematic with all the values for the given points then this will help problem solving.

[Lizzie]

Thank you for all of these suggestions.  They are very much appreciated.  I will try the ones that I can do myself and get some assistance from a friend with a multimeter.  Then last resort an auto electrician.  Curiously since I wrote this post is has started working again normally.  I can lock with the remote and use the internal button.  Very confusing and frustrating. 🤔 I guess it is prudent to wait till it malfunctions again to try and to identify the fault.  

[Tony Prodigy]

10 hours ago, Lizzie said:

Thank you for all of these suggestions.  They are very much appreciated.  I will try the ones that I can do myself and get some assistance from a friend with a multimeter.  Then last resort an auto electrician.  Curiously since I wrote this post is has started working again normally.  I can lock with the remote and use the internal button.  Very confusing and frustrating. 🤔 I guess it is prudent to wait till it malfunctions again to try and to identify the fault.  

That's good to hear Lizzie. At least we can rule out a mechanical issue then. Hopefully, cleaning the internals of the key fob will cure it and no further action will be needed. Toyota's are pretty reliable and I've yet to see one with a defective central locking system.

Key fobs can take a beating over the years, so this would almost certainly be my focus.

All the best