Yaris 08 Passenger Door Lock Issue

[mrtuk]

Hi, have a frustrating problem that I'm wondering if anyone can help with please. (08 yaris sr 5 door)

Problem started a few months ago when random doors would not unlock via central lock on key fob. This affected (intermittently), rear passenger and front passenger doors mostly. Could sometimes be unlocked via lock/unlock button on driver side door. However, rear passenger door usually needed to be unlocked manually.

Sometimes affected front driver side door ... When this happened, had to use key to manually unlock door.

Also, sometimes even unlocking passenger door manually (from inside) it would lock again, so you had to do it a few times before it stayed unlocked.

This is all annoying, but can live with it ... However the problem has now got worse, and the passenger door is now permanently locked ... I cannot unlock it manually from inside, and central locking via driver side door button, or key fob does not work. So, only way to use passenger side at front is to climb across from driver side, or from back seat. Not very practical 😢

Any ideas? I am concerned it's feeling like it could be an expensive job to fix.

[leepulsar]

Common fault latch on door jams try pressing centre locking button on door lots of times until it opens then u will have replace door latch

[mrtuk]

Took it to the dealers today to get quote to fix ... They said 275 for a new lock unit. Fair enough I thought, and said to proceed, however after replacing it they said the back door locks are also not working, and need replacing too. No way am I going to pay for 3 locks, as I am sure it's an electrical problem rather than the actual locks themselves as they have all been working intermittently.

Anyone know if this does sound possible that it is electrical? Or could it be that all locks started to fail at the same time? (Unlikely me thinks)

[snowpaddler]

I have a 2007 Yaris YRS and had a similar problem with the passenger side door lock. The central locking system will lock all the doors and the internal lock mechanism shows that the door is locked.  But when the doors are unlocked using the central locking signal or a key in the driver's side door, all doors unlock except the passenger's door.

I ordered a replacement lock mechanism from Toyota spares for $AU176.  This was disappointing because this part didn't include the electrical connector, unlocking motor or main cog that does the unlocking - arhh!  I ended up opening the old and new parts and moving the motor, connector and cog over.  After reinstalling the part, I had the same symptoms.  What a waste of time and money!

It is interesting that a key in the passengers side door unlocks all doors.  This is because the key mechanically unlocks the passenger's door and toggles a switch inside the mechanism to tell the ECU to unlock the other doors.

The wiring diagrams show that all lock/unlock cabling goes to all doors.  It applies +/- or -/+ directly to the motors in the door locks.  I don't think this is true and think that there are different circuits and relays for each door.  I know the motor in the passenger's door is OK because it locks the door.

The problem can't be in the cabling from the ECU to the passenger's door because it wouldn't lock if this was the case (the same cabling is used with reverse polarity).

So the problem appears to be in one of the 2 relays that toggle +/- or -/+ to the passenger's door lock.  I suspect good contacts in the path that locks the door but bad contacts involved in applying the reverse polarity to unlock the doors.

The fix suggested in the service guide is to replace the ECU - imagine how much that would cost!  My next step is to check the relays in the ECU and maybe replace the bad ones. 

 

[s12erm]

This is happening to our 2006 5 door Yaris T-spirit.

I strongly suspect an electrical problem as when we removed the car Battery and reset the electronics, the problem temporarily resolved (but recurred after a period of problem free use).

If anyone knows of any firmware updates or hacks that are available to work around this issue, can you post them.