MK4 - Passenger door locking/unlocking problems

[boylin]

For the past few months I've been having problems with my 2011 Mondeo passenger side door. It started where the auto folding mirror wouldn't fold out when i unlocked the car, it would fold in fine but not out, i'd have to keep pressing the fold mirror button a few times to get it to eventually fold out properly. Then that sort of stopped happening, maybe once a week but it's been replaced with another problem. Now the door has issues unlocking. It will lock fine when i use the key fob, but when I unlock the car with the fob it'll stay locked from the outside. It looks like it has tried to unlock but hasn't fully as shown in the attached picture. Also when the anti-hijack locks the doors, it'll try to lock but won't fully click in and it'll remain unlocked from the outside.

I took all the door apart and WD40'd all the connectors i could see, including inside the mirror housing under the cover. It didn't make any difference.

I'm thinking either the door control module, or the motor for the locking mechanism is playing up?

[boylin]

I accessed the passenger door module using an ELM and there was a bunch of error codes. I cleared all the codes and restarted the module and the following error codes persist every time. Looks like locking motor has gone?  Also are there any guides on replacing these motor units? Would one from a 2008 fit my 2011 facelift estate model?

B10EC, 15, 68 - passenger door double locking motor / circuit short to battery or open

B1109, 11, 6C - passenger door central locking motor / circuit short to battery or open

[Tdci-Peter]

3 hours ago, boylin said:

Looks like locking motor has gone?

Those codes look like they are from two separate motors. It is more likely that some common element has failed, like a common return or earth connection. This connection could be inside the latch unit, in the door module, in one of the connectors, or in the wiring or earthing bolts used.

The picture below is from the Focus, but it might help show what I mean.

[boylin]

11 hours ago, Tdci-Peter said:

Those codes look like they are from two separate motors. It is more likely that some common element has failed, like a common return or earth connection. This connection could be inside the latch unit, in the door module, in one of the connectors, or in the wiring or earthing bolts used.

The picture below is from the Focus, but it might help show what I mean.

Thanks for the help. I'll pull all the door card off in a few hours and give the earth points a check. I didn't know the two codes above came from two separate motors, thought it was one motor. Anyone know anywhere to check in particular and what I'm looking for? Thanks

[boylin]

Didn't get around to checking it last weekend, I'll do it this weekend hopefully. 

Anyone know where the earth points are inside the passenger door?

[boylin]

Finally got around to taking the passenger door apart again, checked all the wiring and the plugs but they look fine, WD40'd them and put them all back. Can't seem to find any earth points in the door. Checked all the plugs and wires up in the passenger foot-well too.

Still doing the same problem, sometimes it will not lock, sometimes it won't unlock, and sometimes the mirror fails to fold out when unlocking, and i'll have to keep hitting that mirror fold button to get it to fold out.

[Tdci-Peter]

45 minutes ago, boylin said:

Can't seem to find any earth points in the door. Checked all the plugs and wires up in the passenger foot-well too.

Still doing the same problem, sometimes it will not lock, sometimes it won't unlock, and sometimes the mirror fails to fold out when unlocking,

The earth points for the door motors & electronics are most likely outside the door, on the adjacent sill or floor panel. It would not rely on the hinges to provide an earth return. So they will pass through one of the connectors linking the door to the body wiring harnesses.

It is beginning to sound like a dodgy joint in the door electronic module. It is less likely to be the BCM (Body Control Module), as most of the wiring in this is common to all doors. So if all else is ruled out, I guess you may have to try a replacement door module.

But I recall one thread where water getting into the mirror corroded a connector there, and had some odd effects.

 

[boylin]

21 hours ago, Tdci-Peter said:

It is beginning to sound like a dodgy joint in the door electronic module. It is less likely to be the BCM (Body Control Module), as most of the wiring in this is common to all doors. So if all else is ruled out, I guess you may have to try a replacement door module.

I forgot to mention; i swapped both the drivers and passenger door modules over and it's exactly the same. The drivers door works fine and the passenger door still doesn't.

 

[Tdci-Peter]

4 hours ago, boylin said:

I forgot to mention; i swapped both the drivers and passenger door modules over and it's exactly the same. The drivers door works fine and the passenger door still doesn't.

Ok, that sounds like a decent test for the electronic module. I have just re-read the thread, and some sort of mechanical jamming of the locking mechanism seems possible. I think if the lock jammed mid-travel, the module would see the stalled motor draw excess current, which could raise the " locking motor / circuit short to battery or open " error messages.

It is a great pity these DTCs are not more specific, it often seems like the programmer picks one almost at random from the wide lists available. That message sounds like it is a current measurement error, but either too much or too little.

The other possibility, if it is not a connector, is rotting wiring. Once water gets into stranded wires, especially where they flex like at a door hinge, it can eat through the copper, and make them high resistance or intermittent open circuit.

Pic attached is a wire (not in a car) I found to be like that.

I am struggling a bit to come up with a way to separate these two: jamming or bad wiring. A current measurement to the motors would do it, jamming would give high current, bad wiring low current. But finding and breaking in to the right wire is not easy, and the measurement time is very short. Doing resistance measurements through all the power & earth wires is another difficult option.

Opening up the door cover to be able to see the mechanism, then looking and listening during repeated operation might give a clue, or feeling the motor body (if you can) after repeated operation, for excess temperature rise, would also help. Stalling will heat the motor above normal, bad connection would make it cooler than normal. Compare it with the good drivers door if possible.