Hi all,

So I’m on my way back from work and get in the car all as normal. Accidentally hit the back window down button instead of the front window, but then it wouldn’t go back up using either front buttons or the buttons on the back door.
Then I got a message on the convers+ screen saying “Child Lock Malfunction”. 
 

So I’ve tried erasing all stored error codes with my switched ELM327 dongle and read them after a few presses of the child lock button and it comes up with the same error message on the convers+ about child lock malfunction again, however there aren’t any related error codes to the door or the child lock malfunction. 

So at the moment the rear door is completely dead, window stuck down and doesn’t work, the light on the window switch doesn’t illuminate, door won’t lock using key fob so the locking motor doesn’t work, it all sounds linked to one thing causing the problems.

I’ve tried changing the back door module and erased all codes in all modules, and still exactly the same problem. 
Changed the front drivers door module and still the same problem. 
Tried removing the battery and charging it up while it’s disconnected for about an hour, put it back on, showing 13.4v and still same problem. 
Tried removing the BCM from under the passenger foot well and checked that for any damage of burn marks etc, but looks fine. Plugged all the plugs back into the BCM and same problem !
Connection between the back door through the rubber grommet looks fine with no damaged wires in the flex.

It’s the rear drivers side passenger door is the problematic door. Problem is the window is stuck down and I don’t know how to get it back up, might have to disconnect the window motor and put 12v battery on the terminals to wind it up. Can’t leave it open until I solve the problem. Black bag over it last night but set the alarm off, so black bag and had to keep it unlocked all night. 
 

Just wondering if anyone has any other ideas before I take the door card off again and rip open the door lining seal which bud rather leave sealed. 
 

Thanks to anyone with some help. I’ve got electronic stuff everywhere in the garage, wires, good car battery, fuses, multimeter etc, so can test point if you guys can tell me what to check.

Much appreciated.

Got the multimeter out yesterday and checked the voltage at the door hinge wiring loom which clips into the car chassis. I had the other passenger rear side so compare with. 
 

I have 12v going to the working rear door but the passenger side has no voltage at any terminals. 
The rear door module gets its connection from the front module, correct? 

After a bit of further investigation and messing with ELMConfig I read the CCM and it read all the serial numbers and model numbers of each door module but failed to get the info from the faulty door side. 
With more access to modules and em reading error codes, the Drivers Door Module and Passenger Door Module both have an unusual error code that the app can’t decipher. The drivers door module has:

Code: B1A98 - LIN Bus Circuit #1

So I’m guessing a faulty wire between the drivers and the passenger door module?I’m lead to believe after Googling but on a fiesta they say it’s a purple wire? And it’s a single LIN bus communication wire? 

Think you might find water has got inside the front DDM.

There is another thread going on at the moment with a guy having very similar problems with his Mondeo. With his the problem is the rear passenger side door and also front passenger side window. He has removed the PDM and found it badly corroded inside.

See also this :-

 

 

19 hours ago, unofix said:

See also this :-

 

 

Hi, like unofix says, the likely culprit is the DDM. When you say you’ve changed it, was it for a new one or 2nd hand? 
And if 2nd hand, was it from the same vehicle type? 
I eventually cured my issue with the back door by replacing the front PDM. 

 

I replaced both the front and rear door modules, both drivers side front and drivers side back, for exactly the same part numbers and they both don’t make any difference at all, exactly the same problem with them fitted, even with both replacement modules fitted. All the windows and door locks etc work apart from the drivers sidei back door. 

So I dug out the good old Haynes manual and found the wiring diagrams for the door modules. Looks like LIN 1 is a Grey / Yellow cable, not a purple one, that must be for focus’ or others. 
 

Anyway I’m going use my trusty Fluke multimeter out and probe away checking voltages and finding the LIN wire and checking both ends for continuity. 
 

I’ve attached the wiring diagrams for the door modules incase it helps anyone in the future. 
 

I will update when I have found the problem. 

I hope you find a wiring fault, but the only reason I asked whether or not your replacement modules were from the same vehicle is that I replaced my front module with the exact same in terms of model/serial/ etc etc and it made no difference. The reason being different EEPROM programming and probably a different configuration in the LINbus chip. 
As I had no ability to program the module as per factory, it was useless. 
Once I found one from a similar donor vehicle, all worked fine. 
Let us know what you found. 

We might be getting closer to the problem. 

The front door replacement module is exactly the same module, same numbers and FoMoCo stamp but it was from a Jaguar.

Could I clone the original front door module software and clone it onto the replacement jaguar module? I have an ELM327 with the CAN switch.

Yesterday I checked the other passenger side block connector in the door (door to pillar) and found that passenger rear has a 12v feed, so checked the drivers rear door and found it has 0v.

So I unplugged the two plugs at the rear pillar / door grommet and connected an external 12v battery to the two pins (while leaving it unplugged at the door as I didn’t want everything to explode by connecting another 12v source to the car), and the door came online. It was just starting to rain at this point so did the window up using the back door switch and tidied up for the day.

I did one last check yesterday at FA3 in the boot fuse box and it’s not blown, none of the fuses are blown. Checked the fuse terminal and it’s got a +12v going to it. 

Also got the Haynes manual out and the Lin Bus cable is Grey/Blue, (attached photo of page if it can help anyone in the future) found the LIN wire and checked continuity at the module plug and at the front door grommet and the plug at the back door grommet, it was fine. Maybe from there to the door module is damaged, or the 12v feed is damaged somewhere. 

29 minutes ago, boylin said:

We might be getting closer to the problem. 

The front door replacement module is exactly the same module, same numbers and FoMoCo stamp but it was from a Jaguar.

Could I clone the original front door module software and clone it onto the replacement jaguar module? I have an ELM327 with the CAN switch.

Yesterday I checked the other passenger side block connector in the door (door to pillar) and found that passenger rear has a 12v feed, so checked the drivers rear door and found it has 0v.

So I unplugged the two plugs at the rear pillar / door grommet and connected an external 12v battery to the two pins (while leaving it unplugged at the door as I didn’t want everything to explode by connecting another 12v source to the car), and the door came online. It was just starting to rain at this point so did the window up using the back door switch and tidied up for the day.

I did one last check yesterday at FA3 in the boot fuse box and it’s not blown, none of the fuses are blown. Checked the fuse terminal and it’s got a +12v going to it. 

Also got the Haynes manual out and the Lin Bus cable is Grey/Blue, (attached photo of page if it can help anyone in the future) found the LIN wire and checked continuity at the module plug and at the front door grommet and the plug at the back door grommet, it was fine. Maybe from there to the door module is damaged, or the 12v feed is damaged somewhere. 

I did exactly the same as you first time. That is, used an identical module from a Jag rather than a Ford. The programming is completely different. 
 

If you use Forscan you can see if the module appears in the servicing procedures and use the AsBuilt function to restore to factory settings. If you can, I think this will cure your problems. 
If not, as I found, then you’ll have to get a module from a Ford - same model, or transplant the LINbus and EEPROM chips from the old module over to the Jag one. But this is difficult surgery and has the potential to go badly. 
Honestly, I’d just try and get a door module from a suitable donor if you can’t reset the Jag module. 

So I fixed the issue, and the child lock malfunction warning has gone, but had to erase the error codes stored first after I fixed the problem. 
 

I checked the voltage feed to the two plugs in the passenger door pillar to the door grommet, there’s two plugs there and one wasn’t providing any voltage. Compared with the other side door that works; there’s two wires that provide the door module with 12v and the faulty door was at 0v. 
 

So I checked the negative continuity and it was fine, so that’s the ground earth wire that’s fine. 
Probed the positive wire and checked it against the the good earth wire and 0v. Checked the fuses, F03 is the one for the passenger door and that fuse was fine. Checked the fuse point and there’s 12v going to the fuse. So I took the fuse box off from in the boot and checked the back and there was my problem. 
The wire at the back of the fuse box F03 had came loose at the output of the fuse terminal. Repaired the connection and the door came alive.

Had to use switched elm327 to clear all the modules with ELM327 on the PC. Worked and no errors returned. All great again. Haynes book for wiring diagrams is so useful. 

10 minutes ago, boylin said:

So I fixed the issue, and the child lock malfunction warning has gone, but had to erase the error codes stored first after I fixed the problem. 
 

I checked the voltage feed to the two plugs in the passenger door pillar to the door grommet, there’s two plugs there and one wasn’t providing any voltage. Compared with the other side door that works; there’s two wires that provide the door module with 12v and the faulty door was at 0v. 
 

So I checked the negative continuity and it was fine, so that’s the ground earth wire that’s fine. 
Probed the positive wire and checked it against the the good earth wire and 0v. Checked the fuses, F03 is the one for the passenger door and that fuse was fine. Checked the fuse point and there’s 12v going to the fuse. So I took the fuse box off from in the boot and checked the back and there was my problem. 
The wire at the back of the fuse box F03 had came loose at the output of the fuse terminal. Repaired the connection and the door came alive.

Had to use switched elm327 to clear all the modules with ELM327 on the PC. Worked and no errors returned. All great again. Haynes book for wiring diagrams is so useful. 

Great news. Always difficult with electrics. 
methodical testing gets you there in the end. Glad it’s sorted. 

I've been reading all these comments re "child lock malfunction" error message and drivers side rear passenger window won't go up as i have all these errors and was just about to get my multimeter out to check Fuse A3 & AP on fuse board in rear left of galaxy boot area, but first, i'll double check the error/prob still exists.

I open drivers door, sit in seat, close drivers door.

i then depress rear door window button at drivers armrest, and lo and behold, the window lowers!.

I then raise door window button and window closes.

i check to see if the child malfunction message is still showing on display and it is.

I then depress the child lock button on drivers armrest, the yellow light displays and i hear a heavy click coming from the suspect rear passenger door, which fills me with hope, but to make sure it is locking the door, i get out of car, shut drivers door and attempt to open suspect passenger door using the outside handle. It's locked!...this sounds promising.

I double click on my key fob to lock all doors and set alarm, and indicator lights flash confirming system locked and armed. Hooray, maybe it's fixed itself?.... to check, i depress door open button on key fob and hear clicks of all doors unlocking. I open drivers door, sit in seat, shut door. I check to see if "child malfunction message is still displaying, it isn't.

I toggle through "information" menu to get to "messages" and the child malfunction message is still displaying, so i click the "ok" button on steering wheel and child malfunction message no longer displays.

I start the car BUT the "low battery voltage" message displays, i note it but ignore it and run the engine at 2000rpm for about a minute to put some charge in the battery, then turn the engine off, turn it back on again and no "low battery voltage" message displays.

I double check if the suspect rear passenger door driver side can still be opened and closed/locked and that the window can be opened/closed and that the child lock button locks and unlocks the suspect door. It all sounds fixed.

So, in conclusion, either I have an intermittent door controller or more probably, as we've had a long spell of very cold weather, the main battery has suffered and thats why it displayed a "low voltage" warning message and if the low voltage was below what the electronics in the door controller likes, that is ***** up it's logic signalling to open/close the window and lock/unlock the door, so when i start the car and put a bit of charge in the battery, no door problems show up.

My next step is to get the multimeter out and check the battry voltage next morning after the car has sat in the cold overnight. The voltage on battery terminals should be above 12.7 volts. If it's below that, then maybe it's time for a new battery. (fyi, when batteries get below 12.7 volts, plate sulphation problem starts to occur and over time, this can produce an even lower voltage and lower cranking current (Amps ) needed to start the engine)

I guess my battery could be in need of replacement, but i'll prove this tomorrow after a frosty night. (Galaxy is always parked outside, not in warm garage that my volvo and motorbike endjoys.

45 minutes ago, Martin Yates said:

i check to see if the child malfunction message is still showing

Whatever will car manufactures think of next ?

You have a message on the dashboard to tell you when your child is being naughty ! 🤣 🤣🤣

2019 focus child lock malfunction problem,

Child locks don’t work by the button, and if I use my key manually on the door it will lock from the outside, not the inside, can anyone help?

3 hours ago, Chris94 said:

2019 focus

This is the MONDEO forum.

It's funny there has been nothing on the subject of child lock malfunctions for nearly 6 months and then two posters pop up with similar problems in 60 minutes.

2 hours ago, Jason81 said:

Hi, 

Looking for some advice. My 2012 Plate Mondeo is displaying 'Child lock Malfunction'. When checking the child lock on the rear drivers side I found it wasn't working. The door can be opened from the rear seat even when the Child lock is switched on. The window controls are totally unaffected as is the rear passenger door. Any advice? 

 

11 hours ago, unofix said:

It's funny there has been nothing on the subject of child lock malfunctions for nearly 6 months and then two posters pop up with similar problems in 60 minutes.

I've noticed this happening a lot.  We often seem to get very similar questions being asked within a day or two.  I think it must be something to do with the Google algorithms, so the second poster has Googled the issue and this forum comes top of the results.

On 6/27/2023 at 4:53 AM, Chris94 said:

2019 focus child lock malfunction problem,

Child locks don’t work by the button, and if I use my key manually on the door it will lock from the outside, not the inside, can anyone help?

Our 2012 Focus S child lock won't work from the driver's door switch panel, also it doesn't light up anymore.