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tomp87

Focus MK2 fault code - please help!

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Hi all, this is my first post on the forum so apologies if i'm posting in the wrong place! I have a 2008 mk2 focus estate diesel 2.0 TDCI with the following issues...

- The car has been running fine most of the year, but now and again wouldn't start (engine just turns over and when you release the key the instrument panel flashes and says engine malfunction). Occasionally it does start but then goes into "limp home" mode...very rarely though (once i think). The issue was very much intermittent to begin with.
- Recently the issue has been pretty much permanent i.e. no longer intermittent issue and I haven't been able to start it for about a month (not much need for it at the moment!)
- Codes that show up (using an OBD reader) are:
   - U0073 control module communication bus A off
   - P1934 the fault code is not found in the database
   - U0001 high speed CAN communication bus
   - U0140 lost communication with body control module
   - U0121 lost communication with ant-lock brake system (ABS) control module
   - U0131 Lost communication with power steering control module
   - U0155 lost communication with instrument panel cluster (IPC) control module
 
other things to note:
- MPG running a bit low lately (~10ish mpg lower than usual). One of the errors that showed up before was to do with the fuel management control module
 
Any help would be much appreciated!
 
Thanks
 
Tom

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are you aware of the problem with the soldering on the circuit board inside the speedo console unit (instrument cluster) on these cars? there is a common known problem with them. There are youtube videos on dismantling it and resoldering the 32 (i think) pins on the socket for the connector plug. The solder cracks and causes all manner of problems.  The mk2 focus has a High Speed Canbus which is a constant flow of computer data between the instrument cluster and the ECU under the bonnet and a medium speed canbus which has a constant flow of computer data between the instrument cluster and the BCM (body control module) under the glovebox.  At first glance the BCM looks like a fusebox but inside it is a circuit board with computer chips on.   Any connection problems on the 2 can buses causes all sorts of problems. I can not say if your error codes symptoms exactly the typical ones for the instrument cluster problem.

The ABS and power steering are on the high speed can bus. sometimes the high speed canbus problems can be traced to the big connector plug in the engine bay fuse box near the battery. But also corroded connectors in the plugs under plastic trim to the left of front seat passenger's left foot.  The canbus wiring takes a very winding route from instrument cluster to ECU.

My brother has a 1.8tdci 2008 focus and we had very bad recurring  problems similar to yours which ended with me rewiring the whole high speed canbus circuit with new cable and soldered joints. and it's been good (touch wood) for probably a year since then. It was a long old job but I just didn't want to give up on it as it was a nice car to drive when going properly. But the car has proved to be very problematic in the 18 months he has had it, it's been one thing after another. We have both been driving 38 years and this has been by far the car with the most things having gone wrong either of us has ever owned. 

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Thanks very much for the response, no I wasn't aware of the soldering issue but i will look into that. Appreciate the help - Tom

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Hi, I am going to attempt the soldering soon. Do you know whether you can lock the car with the instrument cluster removed? Even if its just the key to manually lock all 4 doors

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3 hours ago, tomp87 said:

Hi, I am going to attempt the soldering soon. Do you know whether you can lock the car with the instrument cluster removed? Even if its just the key to manually lock all 4 doors

That's definitely the Cluster soldering issue, have a look on ebay there are places where you can send it away to from about £50.

You will have to lock all the doors manually and then lock the drivers door with the key.

It's recommended to disconnect the battery negative before disconnecting the cluster

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Hi, I just got my cluster back from an ebay repair shop and I've still got the issue...So either the repair shop didn't fix the issue (I am checking what they did to the unit) or the issue is elsewhere. Does this point to the CANbus wiring do you think? Or likely something else that I could check? Is next step to check the connectors in the passenger footwell or engine bay fusebox?

I still have the same 7 errors as before and now strangely the display is showing -59degC for the temperature monitor, which it wasn't before...wondering if this provides someone with any clues? The engine does turn over much more frequently now (not sure if that helps the investigation)...before it pretty much only turned over once and then i got the engine malfunction warning on the display.

I checked the battery voltage too and this was showing 12V (car has been dormant a few months now), I wasn't able to monitor it whilst trying to start the engine. Is it possible my battery is now too low and some of these errors are "false" errors caused by a lack of battery voltage?

Thanks for all the help so far, much appreciated!

Tom

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We had a problem with outside temp display showing a dash. At the same time the indicator lights on the dash didnt flash , nor could you hear the indicators and the  blue high beam light did not work. This was due to break in the medium speed canbus (not high speed canbus) between instrument cluster and the fuse box under the glovebox. Don’t know if low battery might cause all this. Rule it out by charging battery. And then if no good move on to checking the wiring connectors. Don’t have any hammers nearby otherwise you may feel the urge to smash the car up . Hope you get it sorted. 

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this is link to the stuff I posted last year about the canbus problems (lots of it - two pages). Hope you don't have to do all this to fix it

 

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thanks for the advice, much appreciated! I will start with the canbus connections, the ohm meter reading for the can bus termination is a useful bit of info too!

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Sorry the cluster repair did not fix this.

Next, I would look at the BCM it is not uncommon for these to get water damage on the board from a drip from the HVAC

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Hi all, Only just got round to properly looking at this (haven't needed the car!). I've taken enough bits off the car now so that I've got proper access to the BCM, C90, C112 and C113 (what a pain that one is!). I started with a fully charged battery just to rule that out of any potential issues.

First of all I tried starting the car, the starter motor turned over but you could tell it just wasn't properly engaging (due to the fault i presume). When i released the key the warning "engine malfunction" came up again as per the last few times I tried this.

i then measured the ohms output on the ODB connector and strangely got 60ohms...this must have been a freak occurrence though as every time since it has been 120. It's possible that after trying the measurement first time I then repeated with the ignition on...would this have caused an issue? I wouldn't have thought so, but you never know. My following steps were then:

- C90 unplugged from under bonnet in fuse box. ODB still read 120ohms

- instrument cluster unplugged too, reading now infinite ohms

- C90 plugged back in and reading returns to 120

- C90 unplugged again, but cluster plugged back in...120 reading

- C90 and cluster both plugged in...still 120 (you would think two 120 resistors would now give the normal 60 ohms...I'm thinking this may be a clue?)

- C112 disconnected, still 120

- C113 disconnected, still 120

- Checked the BCM for signs of water damage and unplugged/replugged in all the connectors 

Now when I try and start the car I get "transmission fault" instead of "engine malfunction" and the car does not even let me attempt to start it on the first go (like it used to)

I am thinking that the issue could be between the cluster and C90 as both of them cause a reduction in ohms by themselves (ties in with a resistor appearing on the bus), but never down to 60ohms with 2 in parallel...I'm struggling to think of what to try next. Any help would be much appreciated! I don't have a full wiring diagram for the car and not sure if this exists or not so at the moment I am a bit blind to where to look next. There must be a break/dodgy connection somewhere on the wiring loom I would have thought? Or the cluster I sent away for repair did not get properly repaired? Any tests I could try on the cluster?

Wondering if I now need to try continuity testing between the ODB, the cluster and C90? I haven't looked at the PCM yet as I believe this is behind left front wheel and I have no driveway so its a bit of a pain to work on the car in the street

Thanks for all the responses so far, it's really appreciated. Cheers - Tom

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There are some .pdf circuit diagrams here. Hope that's helpful.

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I reckon it's the flux capacitor malfunction

Doc brown should be able to fix it in time.

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🤣 sorry, Wales in total lockdown again and to many kronenbourg 1664s. I'll shut my mouth now.

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