Hi all. Had an issue earlier in the week where my mk2.5 focus 1.8tdci went into limp mode. Restarting the car eventually sorted the problem. However the next day all my dashboard lights where on although the car drove ok. Called rac who diagnosed fault as above along with injector fault. I'd like to know if a faulty module can cause limp mode and how easy are these modules to replace/fix. The fault was reset and at the moment the car is running ok. Any help would be appreciated.

Thanks, Mat

The mk2 doesn't use a BCM, but rather a GEM (and I doubt the GEM would cause limp mode, it's more likely to be the ECU).

The GEM is part of the fusebox, so pretty easy to get to and swap out. Before you remove your current GEM, you'll have to backup the data using ELMConfig or Forscan (otherwise the central locking and maybe a few other things won't work). Then once you install the new module you can restore the data in the same way.

My brothers 2008 mk2.5 1.8tdci was a nightmare with all sorts of problems caused by dodgy connectors. Ecu is under the left hand headlamp. There is a fuse box above the front passengers feet which is actually much more than just a fuse box,and there is the instrument cluster. They all have computer chips in and need to communicate computer type data between them all continuously on the high speed canbus and medium speed canbus. Any breakdown of connections causes all sorts of problems. Keep your fingers crossed that it stays ok. On my brothers car I eventually solved it by rewiring the high speed canbus   But due to many many other things subsequently going wrong we took the car to be crushed as it was so problematic and we felt we could not inflict it on anyone else.

There is another problem with the soldering of the connector pins on back of instrument cluster. Needs dismantling to resolder on the correct side of circuit board, this has affected a lot of mk2 cars but I don’t know if mk2.5 suffers as much. 

That sounds like the instrument cluster solder joints are going down.

Read codes (not in instrument cluster)

If you have loads of faults saying "lost communication with (bla, bla, bla) and the main one is "THEFT DETECTED" then the instrument cluster needs repairing.

GEM can cause faults too if it's got water contamination.

Drop fuse box below glove box and have a look at the connections, if there's green fur on them then the GEM is damaged, a good second hand one can be fitted and configured to your car using Forscan.

A second hand cluster is not recommended as you will need to program keys and adjust milage

It'll be the cluster issue though, search Ebay for "Focus Cmax instrument cluster repair"

YouTube videos can show you how to do the soldering on instrument cluster. But if you are a soldering beginner I wouldn’t recommend trying it yourself, it is quite small bits of soldering that a beginner could ruin. I think something like a tv repair guy(do they still exist) might be ok for it. Eg take the thing apart and take circuit board to the guy. It’s then a 5 minute job if he has a steady hand and has the soldering iron heated up. 18 pins I think. I have done one but I wouldn’t do someone else’s in case I cocked it up.

11 hours ago, isetta said:

like a tv repair guy(do they still exist)

Probably not lol. Most TV's are so cheap nowadays it works out not much more money to just buy a brand new one. The expensive OLED ones mostly get replaced because the screen burnt out, which is impossible or just as expensive as a brand new one too.