Wednesday, December 16, 2015

DOOR LOCK PROBLEM ON POLO 9N

DOOR LOCK PROBLEM ON POLO 9N


For the past week or so, I've noticed some peculiarity  with my VW Polo's left side  front passenger door locking mechanism. To risk stating the obvious, my VW Polo is a right hand drive car. Its auto lock feature is enabled, so when I drive and reach about 15 kmph all the doors lock simultaneously and the sound made by the four solenoids are clearly audible when this happens. But then, the front passenger door immediately unlocks itself. Initially it was the sound of the solenoid in the left passenger door that alerted me to the fact that it locks then unlocks itself.  

Physically, all four door buttons/knobs  are retracted at 15 kmph, three stays down but the left front passenger door buttons/knobs pops back up again. After this happened a few times,  I re-locked it  by pressing the internal central locking button on the driver's door panel. The left passenger door responded to the central locking lock instruction by re-locking but then immediately unlocks itself again. It just doesn't seem to want to stay down.

Thinking that it was just an electronic glitch and that the door might still be locked, even if the button jumps up. So I stopped the car, rolled down the left passenger window, climbed over the console, stuck my hand outside and pulled on the door catch. Surprise, surprise the door opened.  So I thought to myself, this isn't good, in fact it really sucks.  It's a huge safety risk driving with an unlocked door, especially considering the amount of bag snatching and car hijacking that's been taking place of late. 

Thieves and criminals hanging out at stop signs and at a traffic lights patiently await the opportunity of an unlocked door coming their way, so that they can jump into your vehicle and rob you. I know of a case when three villains jumped into a nurse's car and forced her at knife point to drive to an ATM, to withdraw her daily cash limit. They then held her hostage until after 12:00 the evening just so that they could get the balance of her money from her account which was less than her daily limit for the next day. Fortunately they didn't harm her, but her nerves were totally shattered.   Anyway, what I discovered much late is that when the passenger door button/knob pops up and I can manually press it down, and it doesn't pop up thereafter and the door stays locked.

Anyway, this door button/knob popping-up  started to irk me and it was getting flippen irritating, so one afternoon when I got home from work, I decided to tackle the problem. I switched off the engine, removed the key from the ignition, and all the doors unlocked simultaneously, which is absolutely normal.  So I re-locked the car with the fob remote key and all the buttons stayed down as they should. When I depressed the fob remote key unlock-button twice in quick succession, and all the doors unlocked which is also perfectly normal. From this I deduced that the electronic circuit responsible for unlocking the passenger door must get its power via the ignition switch, since it only unlocks when driving at 15 kmph and not whiles it's stationary and therefore  there has to be a dedicated switch in each door. 

But before I start taking things apart I needed to make absolutely sure that the problem is in the left front passenger door.  I once again used the fob remote key to lock  all the doors to make sure that they stayed locked, which they did. When I unlocked the Polo with the fob remote key, only the driver's door unlocks which is perfectly normal. But within 3 seconds the left passenger door also unlocks, and that's not normal. So I realized the problem is specific to the left passenger door yet I needed to make absolutely sure.

Sitting in the drivers seat, I  turned on the ignition and opened the drivers door and saw the  red light, door-open icon in the dashboard instrument cluster turn on. I repeated this process on the front passenger and rear doors, as well as the boot lid, all of which activated  the red door-open icon except the left front passenger door. The next test was observing the interior light. As I opened the driver's door to get in, the interior light turned on, so I waited for the light to automatically turn off. I then reopened the door and the light turned on as it should. I repeated this action on the other doors which also worked as they should, except the front passenger door that didn't register that it was opened because the interior light stayed off.  

From this I deduced that both  the instrument cluster door-open icon and the interior light is powered from the same switch in the door which is actually  intermittent when not short circuit. Then I got out my laptop and my VCDS cable, rigged it up and Voila! With the all the doors wide open, as can be seen in the image below, the passenger door switch remained closed.




As can be seen in the above image, with all four doors open, the  software
still sees the passenger door is closed
As can be seen in these images the door and trunk Measuring Value Blocks are 005, 006 and 007. With all the doors closed, as can be seen in the images below,  the state of the passenger door switch didn't changes at all. So just for the hell of it, I banged the passenger door a few times hoping that the switch would budge because I'm certain it was stuck in place rather than the contacts burnt together. 



Now that the preliminaries are out of the way,  I can finally get out the screw drivers, spanners and the torx wrench and dismantle that pesky door mechanism. The following pics gives a fairly good idea of what it entails to remove the door lock; and on a scale of 1 to 10 with 10 being the most difficult I give it a 7. Removing and replacing the steel trace link that fits between the exterior handle and the lock is quite a challenge if you  have large hands. 


The door panel before dismantling it
The plastic cover removed to expose the screws.
Removing door handle screw with hex key
The inside view of the door panel with the electric window plug unplugged
The slide mechanism mounting plate with all its screws removed
Removing the torx screws that secure the door lock
The sliding window removed from its clamps and stored safely
Screws of the backing pate, the inside door handle, 
the door lock and the inside door lever
The passenger door lock with the micro switch dangling on its blue and red wires

I sprayed the the micro switch with some Q20 multipurpose lubricant  and flicked it a number of times. I also cleaned the the metal pawl that activates the micro switch. It has a little notch in it, that fills up with grime. I suspect it is this grime and plastic burrs that cause the micro switch to misbehave.  I used two straight pins to pierce the insulation of the micro switch wires in order to connect my Fluke multi-meter so that I could do a continuity tests.

Continuity measurement of the micro switch in its normally open position 
Continuity measurement with the micro switch depressed -closed position.
The steel trace link between  the outside door handle and the lock.  It is 
quite difficult to remove and put back especially if you have large hands.
The door lock "question mark looking" lever, is where the 
short steel trace cable links into
The steel trace must be held in the horizontal  position before it can 
be inserted  into place.
Showing the steel trace link in place, but it has to inserted during 
assembly when the lock in secured to  the door frame.
Several other VW Polo owners have had similar problems with one or more of their doors. For example: When you lock the car with the inside central locking button, the left hand side passenger door does not open when it is unlocked, so the driver has to roll down the window an open it from the outside. I clearly remember that both my Golf 1 and Golf 2 had door lock issues and a replacement lock was really cheap. In fact it was less that the price as a pack of 30 cigarettes. But times have changes and considering the replacement cost of a VW Polo door mechanism (R900 -R1200 excluding labour) and what a shitty job it is to replace it, most drivers just learn  to live with it.  The nature of VW central locking issue can range  from mechanical to electronic, from a sticky micro switch, to cracked/dry solder joints on the printed circuit board. Sometimes  grime / builds -up between the micro switch and its activator, so give it a good clean and spraying the micro switch would be wise once the relevant lock has been removed. 

I know of a VW Pasat that had a similar issues. When the car is unlocked with the fob key neither of the inside nor the outside handles would open the door and since the door needs to be open to repair/ remove  the lock, the car eventually had to go to the agents who charge a whopping R5500.00 to fix it. At least if the other doors had a keyhole to open them, it would have been so much easier. But it is all about cost saving for manufacturers.

Other issues

Central Locking, central locking problem, doors unlock, doors will automatically lock, remote key entry to unlock all the doors, remote unlocking, dealing with locking unlocking issues, can open the door from outside nor inside, remote not working on left passenger door, front passenger door immediately unlocks itself, door unlocks automatically, Doors lock with fob key  then unlock themselves, it locks and then unlocks,

27 comments:

  1. I have exactly the same problem - only difference being that the door open light does come on when I open the passenger door with the ignition on.

    ReplyDelete
  2. The front passenger door lock has three micro switches - one external to the motor housing and two internal. The switches are well sealed against ingress of dust and being Cherry switches they should be very reliable. The pc board inside the motor housing is , however , not well made. On my lock the connector pins 3 , 5 and 7 had developed "dry joints" with pin 7 having almost no connection to the pc board. All the rest of the solder joints on the pc board were OK.
    My fix:
    Open the motor housing taking care that no parts fall out and /or lose orientation. When separating the two halves of the motor housing it is not necessary to remove the locking toggle mechanism ( metal and plastic levers operated by two toggle springs ). Note the orientation of all pins and levers inside the housing then remove the pc board with the motor and actuating slider. Clean the protective coating off all solder joints on the pc board then de-solder and re-solder all of them one at a time ( if you de-solder all joints at once some of the components could fall off the pc board ). Use a good quality solder ( I used Kester ). Clean the solder flux off the pc board with acetone and , when it is dry , re-coat the exposed solder connections and lands with protective lacquer or nail varnish.

    ReplyDelete
  3. Thank you Hoopie , resoldered pin 7 on the board and voila my lock is fixed. I can't believe that manufacturers still can not get their soldering right especially VW. The lock is a safety item so they should pay more attention to their manufacturing process.

    ReplyDelete
  4. my front passenger door lock it totally busted, hardly even moves when i 'unlock' it. My rear passenger door lock just unlocks itself ( think the mechanics just swopped the front left with the rear left lock (another story). Looks light i have to re-do those locks myself.

    good to see someone has managed to blog about it!

    ReplyDelete
    Replies
    1. Hi Sebastian

      Thanks for your feedback. Have a look at https://volkswagen-polo-highline.blogspot.co.za/2015/12/door-lock-problem-on-polo-9n-for-past.html where I've dismantled the front passenger door. The latest that has come to light is that there are dry solder joints on the PCB of the lock mechanism.

      Delete
    2. Hi Faried.

      Your article is great! I will definitely be dismantling the door lock this weekend and getting my hands dirty.

      Delete
  5. My car the door also shoots open while driving. but I still don't understand what can be wrong.

    ReplyDelete
    Replies
    1. When the door unlocks on its own after you'v locked it, then there is definitely a problem with the lock in question. You could change the lock, which is fairly expensive or you could do a DIY. The micro switch in the door could be faulty or it is opening and closing when its not supposed to, because there is dirt and grime between the micro switch plunger and its activator. Of late solder joints on the pc board seems to be the main culprit since it is always the same dry joint on every lock.

      Delete
  6. On my polo vivo the remote just stopped working. I now have to manually lock and unlock the doors. All fuses are ok. Cracking my head

    ReplyDelete
  7. Woahh ! hi volkswagen! Hi dear ! You have a good article and share, please write a lot of sharing articles too! Our side provides smart door lock, please visit our web site khoa cua van tay ! thank you very much

    ReplyDelete
  8. Can anyone help my n/s/f door will not open I have a polo 12 54 plate

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  9. Hi, my passenger front door is lock and doesnt open from inside or outside, beside that both front doors dont open with the remote key, only manually and only the drivers door, can someone advise please? I have a polo

    ReplyDelete
  10. I’m looking for installing CISA locks on my in my home as there have been so may reports of thefts. Thanks for this informative post it was very helpful.

    ReplyDelete
  11. My polo vivo doesn't lock from inside central lock all fuses are okay. what could be the problem? Please help anyone?

    ReplyDelete
  12. My polo vivo doesn't lock from inside central lock all fuses are okay. what could be the problem? Please help anyone?

    ReplyDelete
  13. Hi my central lock on the door in my polo is not responding when I press it and the remote as well not responding I don't know what could be the problem so now my car is not starting at all. It just crank.

    ReplyDelete
  14. Hi I've just learned today that my 2012 polo front passenger door it's not responding to the central locking what could be the problem

    ReplyDelete
  15. Hi my 2017 VW Polo Vivo, it locks itself always Wen I drive off which is normal but unlocks itself when am driving like if I hit a bump or potholes and central lock button is no longer working the one on the dashboard, it sound like theirs is something that works with central lock which is dead behind the Cabion because even if it's locked while am inside n I hit Cabion by feast it unlocks itself, please guys assist me 🙏🙏🙏

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  16. My polo doesn't open with the remote key I don't know why only open manually any advices?my remote is working battery is fine.
    When I open it manually the alarm sounds start to pi pi pi(alarm sounds)

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  17. Hi my polo vivo 2011 just decided not to lock/unlock with the remote when i pull out the fuse and re insert it wil deadlock one of the other doors any advice

    ReplyDelete
  18. Hi,

    Polo n9 2005. R/H Drive. Both left doors deadlocked. Manged to follow online videos and force off interior card on back door, drill hole to remove T-screw then replaced the entire mechanism.
    Front door was worse as the card cannot be removed without damage as it returns under the sill and is attached with screws. Either the card or the door needs to be replaced. Found a door shell 1st so used the angle grinder to remove the door, swapped everything over onto the new shell, replaced mechanism and all should be good. Just having some issues with the door handle barrel and assembly.

    ReplyDelete
  19. Hi guys, can anyone recommend someone to repair or replace the doors in jhb, just got my car back and it's still not right, both left doors are unlocking itself, even when manually locking it thanks

    ReplyDelete
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    ReplyDelete
  21. Central locking on key and spare key just stop working what can possibly be the problem

    ReplyDelete

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