Technical Diesel Central locking doesnt work

[miskofff]

Hello,

I have an issue with central locking in Ducato 2007 gen 3.

The problem is that I can't lock the car. When I'm pressing the open or close button (on the remote controller), the system indicator illuminates as expected, indicating that the command is being registered. However, no mechanical action occurs and the doors do not open or close. The center console light one the lock button light also functions normally, suggesting that the input is detected but the door mechanism does not activate.

That's the errors which I've scanned with MultiEcuScan:
B102A Door lock relay
B102B Cargo area lock relay
B1029 Door unlock relay

So far, I have replaced the M080 module (I have two units with the same part number). After installing each one, the same error codes appear and the issue remains unresolved. Additionally, I have replaced every door lock in the vehicle, but this did not solve the problem. The sliding doors operate normally. I also found information suggesting that resetting the BCM might resolve the issue. I attempted the recommended procedure by disconnecting the red wire, waiting two minutes, and reconnecting it, but this did not fix the problem.

I already made a post about that, but I didnt get any valid answear. Additionally after that was moved to the wrong section with older ducato.

Ducato - door locking problem | FIAT Ducato (Gen 2)

Hello guys, I'm struggling with my Ducato 250 2007, the central door locking is not working. When I push the key open or close, the indicator will illuminate (same as normal operation) but there is not action on the doors. (even the light on the middle of the console works). I cant close the...

www.fiatforum.com

At this point, I have no idea how to solve this problem. I have tried everything I could find, but nothing has worked so far.

Have a nice day,
Jedrzej

 

[Mike1alike]

Check and clean the connectors on the system. Relays and cables and all. Use contact spray. Oxidation is your culprit.

 

[miskofff]

Already checked. Also every cable with going in and out M080.

 

[Mike1alike]

If cleaning the connectors didn’t help, it might be worth checking the wiring looms where they flex, especially the boot/tailgate loom. On many Fiats the wires can break inside the insulation from repeated opening of the boot, and that can stop the central locking from working.

 

[miskofff]

I already rebuild wires in the rear doors. Check everything regarding the signal. Nothing is going out from M080.

 

[Mike1alike]

Can MultiEcuScan activate the locks in the actuator test, or do they not respond at all?

 

[miskofff]

I didnt check that, where I can find that test?

 

[Mike1alike]

Yes, MultiEcuScan should have actuator tests for the door locks.
Go to Body Computer (M080) → Actuators tab.
There should be tests like:
Door Lock Relay
Door Unlock Relay
Boot / Cargo Lock Relay
Run those tests and see if the locks react or if you hear the relay click.
If nothing happens, measure voltage on the BCM output while running the test. That will tell us if the Body Computer is sending the signal or not.

 

[miskofff]

Ok, what if body computer is not sending the signal?

 

[Mike1alike]

If the Body Computer actuator test does not trigger the locks and there is no voltage coming from the BCM outputs, then you need to check a few things before blaming the Body Computer itself.
1. Check the fuses that power the central locking system and the Body Computer.
2. Clear the fault codes and run the actuator test again to see if the faults return immediately.
3. Check the wiring between the BCM and the lock relays/actuators for shorts or breaks.
4. Check if the BCM receives the lock/unlock command (from key, button, or remote) in the “Parameters” section in MultiEcuScan.
If the BCM receives the command but still does not output anything during the actuator test, then the BCM output stage for the lock relays may be faulty.

 

[miskofff]

Great, I will check that tomorrow. I'm pretty sure that I can see that BCM receives the command (there is information when I click the button on remote controller).
Even when cleared, the faults appear immediately after clicking the locking button on the middle console in the car or pressing the button on the remote controller.

I would like to mention one more important detail. The problem started when I discovered that two cables coming from the M080 module toward the rear of the vehicle had been cut. I reconnected these cables. At that time, the central locking inside the cabin was working, but only for the front doors.

After reconnecting the wires, I locked the car using the remote controller. The car locked successfully, but I was unable to unlock it afterward. I tried both the remote controller and the button on the center console, but neither worked. Eventually, I had to open the door manually from the inside using the handle.

After this incident, the fault codes appeared and the central locking system stopped working completely. Even if I disconnect the cables again (as they were before), the system still does not work.

Based on this behavior, it seems possible that something in the BCM may have been damaged or malfunctioned.