Ecu multiplug problem

[Leighton198]

Hi all my 2015 1.6 diesel mondeo has had an issue recently where it fails to start in the morning and throws all sorts of warnings at me low oil/engine overtemperature etc , after getting recovery out it appears the ecu multiplug to the fuse box was loose and some firm pressure to to reconnect it was all that's needed to get everything working fine , question is has anybody else experienced this , is it something that can be fixed easily to stop it happening again or is there a deeper lying issue with the plug?

[unofix]

7 hours ago, Leighton198 said:

appears the ecu multiplug to the fuse box was loose and some firm pressure to to reconnect it was all that's needed to get everything working fine ,

The design of the plugs are such that they latch in and are held very firmly once the lever is pushed fully home.

Is the problem you have with the passenger compartment Body Control Module (BCM) which is part of the fusebox OR is the problem in the engine bay ?

[Leighton198]

I recently changed the cabin filter could that have something to do with it ? So far the only fix is to apply a bit of pressure to the top of the plug in the engine bay , Apologies I'm by no means a mechanic haha

[rd457]

Yeah if you had someone replace the cabin filter they may have likely disconnected one or more plugs from the passenger fusebox to help get it out of the way and they probably just didn't reconnect it properly afterwards. Certainly on my focus doing it this way makes the job much easier. The main connectors, as unofix described, have a lever to help secure them in place. You push and hold the connector down then push the lever into position to lock it in place. This must have just simply been done wrong and hopefully has now been done right. So long as it has and it's not broken (the recovery person probably would have noticed and told you if it were) then it should be fine now. I wouldn't worry.

[rd457]

Oh wait, maybe I'm misunderstanding you. Are you saying you're still experiencing problems and having to apply pressure to the connector to get things to work? If so then that sounds like one or more of the pins may have gotten bent and only making an electrical connection when you're pushing down on it. You should unplug the connectors and look to see if any of the pins are obviously bent and if so straighten them.

[Leighton198]

So yeah happened again leaving  work this evening now ,I've pulled apart said glovebox to check for loose wires but no luck so far will double check the pins on the ecu plugs under the bonnet , proper nightmare couple days 

[rd457]

I might have led you in the wrong direction here after your mention of the cabin filter replacement. Going back to your original message it was unclear what you meant by "ecu multiplug to the fuse box", hence unofix's question which you didn't answer. With the mention of fuseboxes and multiplugs and replacement of the cabin filter I was picturing the cabin filter replacement to be similar to that for my focus, but I've just looked at some youtube videos and I don't think it is.

If you look at the following video from a Mk4 Mondeo you can see what I was picturing, you have to remove the passenger footwell fusebox (the white box) to get at the location of the filter:

However for your Mk5 Mondeo the filter seems to be in a very different location that does not involve touching a passenger footwell fusebox:

So it's back to unofix's original question, effectively where exactly is this plug you're pushing on located? Can you please provide a picture of that.

[Leighton198]

Apologies so yes I'm having to apply pressure to the two plugs shown in picture I found online to be able to get the engine to work properly and turn over , as he said these plugs(probably the wrong terminology)are very secure however applying downward pressure to both of them seems to do the trick 

[Leighton198]

I have a mechanic buddy who's going to take a look this weekend hopefully ,would certainly like to know the potential issue and resolve it without having to bite the bullet and take it into the dealership haha

[rd457]

Okay, great 🙂

There's certainly no reason for that to have been touched to simply replacing the cabin filter. I'm sure once your friend takes a look they'll find an obvious and easy to fix explanation for the poor electrical connection.

[DaveT70]

Probably a loose terminal in the connector body or contamination on one of the pins.

Disconnect and look at the wires in the connector.

Do any look as if they have fallen away?

Pull on each individual wire to see if it pull out, if so latch back in.

Spray some silicone spray in the connector and connect and disconnect a few times to clean the contacts to see if it goes away.