another central locking snag

[alimac81]

Hi, had a search and couldn't find a solution so here goes. Central locking recently packed up, but the boot still works off the key fob and key. got these error codes of vag com 00928, 00929,00930, 00931 locking module central locking all four doors implausible signal. checked the diver side door for corrosion on all the usual clips, took the door unit apart to check for loose contacts and corrosion all looks good. swapped the central convenience unit and still no joy (do you need the key from the car the unit came from?)

Any ideas would be appreciated as im not to clued up on the octy mk1, only had it for a few months

with regards

Ali

[rwbaldwin]

You usually get this set of four fault codes when you replace the CCU for an incompatible unit. Did the part codes (including any trailing letters) match?

[alimac81]

Yup part codes match, and I had the fault codes before I touched the ccu. Heated door mirrors are flagging a fault code now, oh the joys

[pauldazzle]

Check where the door harness enters into the drivers door from the A frame,  it's common for the wires to break there.

[alimac81]

Removed the door loom today, took off the loom tape and checked it all, seems fine. I also did a voltage check on the plug which connects to the lock module, I don't know the correct voltages for which pins, but I was getting 11.2v on all pins apart from the brown (earth) and a gray and black wire.

[mushtafa]

To have all of these different faults, I'd be looking for a common source like main voltage feed wire, main earth, etc

[alimac81]

I think you might be right, slaved in a new door lock unit today and the same fault remains.  I am still unsure about the CCU, as the unit I slaved in was 2nd hand, do they need setting up on VAGCOM? or is it plug and play?

[alimac81]

Slaved another CCU into the car yeasterday and recoded it to my key just to double check the CCU isnt the cause and still have the same fault.  I noticed that it was flagging up S contact intermittent or not signal on the VAGCOM as well.  Decided to fit a new ignition switch i had lying around cleared the fault codes, and disconnected my radio and managed to get it locking and unlocking off key fob.  I should mention that i soldered a wire onto the switchable 12v feed from ignition switch for my radio which is why i removed the radio to see if it was somehow causing issues.

        Ok so it seems like im getting somewhere, only it then decided to stop working again!  Couldnt get it going so i got ****ed off and called it a night.  Rebuilt all the trim around the steering wheel after refitting the original CCU, and refitted the stereo, drove the car out of the workshop and hey presto central locking started working again! It preceeded to work fine for the rest of the evening until this morning when it worked when i unlocked it but when i got to work, stopped again.... Confused.com   

 

Any insights anyone?  Just to confirm all doors wont unlock/lock off remote or key, boot locks/unlocks fine off both. 

[alimac81]

Ok, I made up a jumper lead from the ignition switch to pin 17 of the CCU to rule out the S contact being the cause of all my woes. fault code gone, C/L still broke.  I've also done a continuity check on the ground wire, and get about 26 ohms.  Not sure if this is good or bad but it proves the earth is there.  Im getting a Haynes book of lies soon so this will hopefully have more info in wiring diagrams.

[alimac81]

Ok so latest on my knackard central locking, managed to fix something unrelated to it, but I posted about before.  The elusive s-contact error code, and no switchable 12v at stereo, which turned out to be a fuse that wasn't even fitted!! don't know why it wasn't but replacing it fixed that issue, Fuse number 10 which I think is labelled as engine petrol control, which is why I didn't think about it before until I got a wiring diagram!

      My C/L fault and fuel filler cap fault remains!  the earthing is all good on both CCU and Fuel cap release, however the voltage is doing some funny things which may or may not be an issue?  When I try and open the filler cap (which shares its 12v supply with all door locks) the 12v drops right off and no actuator movement.  Ive tested the actuator and it works, switch is all good, and again earthing is all good.  will try and get a pic of the wiring diagram up at some point, if anyone has any ideas as to a possible fix then would appreciate the input.

[Rob1971]

Just a thought, you may be getting 12V, but that doesn't always mean you are getting enough juice (Amps) which may be as mentioned earlier - duff cables. I once tested my motorcycle battery which was showing 12V but it was in fact almost dead! I read these posts with interest as I have one door CL playing up - almost always locks when using key fob and it rarely locks when using the locking switch on the door panel! Oh the joys.

[Bowders1]

I had a similar fault with just my rear drivers side door. Central locking on remote would not open close just that door. After hanging in a compete spare door to b pillar loom plug, the slave door worked with remote. Long story short. The door loom was fecked. Maybe you have a loom or wiring fault

Sent from my Samsung S3

[mushtafa]

 

This may help perhaps?

[mushtafa]

A11 Multifunction control Unit

M46 Central locking motor driver

M48 Central locking motor passenger

A195 Door function control module (driver)

A196 Door function control (passenger)

A213 Door function control (left rear)

A214 Door function control module (right rear)

M47 Central locking motor (left rear)

M49 Central locking motor (right rear)

M69 Central locking fuel flap motor

S236 Fuel filler flap switch

M58 Central locking motor (boot)

[mushtafa]

See attached image, should be bigger than the one I posted above

[alimac81]

Thanks for all the info, I think I will use the fuel filler cap release servo wiring as a fault diagnosis tool, and disconnect each door one at a time, and see if the flap releases.  This should hopefully narrow it down to a single point, or door. If it doesn't, I assume then that the snag is somewhere in the dash etc  . I also thought that maybe the battery is on its way out, but im getting no other issues power related, starts first time with ease. 

[alimac81]

diagnosis update if anyone is interested, I tracked down the source of the problem for inop doors and fuel cap release as being a high impedance in the 12v supply line.  It looks like it is somewhere in the wire that goes from the fuse box, to the terminal which then goes to all doors and fuel cap.  Slaved in a 12v supply direct from the battery to one of the doors (unpinned the existing suspect 12v supply) and the door unlocked and locked off the fob.  I slaved 12v into the existing harness for all doors as well, and all doors locked and unlocked (my back right door also un-deadlocked itself, bonus!).  All ive got to do now is find the source of the high impedance in the 12v supply wire, or bypass it with a new wire..... The second option will probably be the easiest!

[alimac81]

Looks like this one is solved, I have bypassed the damaged wire from fuse 38, and spliced into another wire (Red with yellow stripe) which I know is good, located in the drivers side sill.  Central locking now fully working, along with the fuel filler cap release and heated mirrors.  Didn't find the cause of the high impedance but I imagine that would involve ripping out all the wiring looms in the dashboard.  Big thank you to all who posted up wiring diagrams and gave advice

Edited 18 November, 2013 by alimac81