Hello, I hope the following is of assistance.
The 2 codes you need to investigate would be the glow plug code (P0380 at a guess) and fuel pressure valve (P0087, P0089 or similar).
Out of the 2 I would say the fuel pressure concern, around 90% of the time this is caused by a fuel filter concern which means the engine management can't control the fuel pressure, if the pressure goes outside the preset parameters then the engine management will reduce power to prevent any possible engine damage. When you turn the engine off and restart as the fuel pressure is OK the engine returns to normal running until the fault is detected again.
If there is a glow plug concern then this is either due to water getting into the glow plug relay or a fault with the actual glow plugs, if there is power to the glow plugs when you turn the ignition on then this suggests the relay is working OK.
The fan performance wouldn't give a lack of power, cooling fan concerns on this model are usually due to the fan control module failing, this is part of the fan and was subject to a manufacturers recall a few years ago.
The CAN fault is usually U1900 and never affects the running of the car, the code seems to be set on most Focus in error.
Start with replacing the fuel filter especially if it hasn't been changed within the last
10000 miles as I've seen many filters where they have caused problems well before the specified replacement interval.
I hope this helps, let me know if I can assist further and I'll reply as soon as I'm able to.
Thanks. But if it is a fuel filter problem why the different codes & not just the fuel pressure valve one? One other thing why did it stop failing after a diagnostic check?
I've given the possible causes of the codes however there's no indication of how long any of the codes have been in the PCM, the glow plug code may be an old code or any of the others may be, In my opinion the fuel pressure concern would be the code most likely to match the symptoms. If it was a glow plug fault causing the message I would expect the message to be displayed more often.
You say the fault went after the check but from your description the fault is quite intermittent to start with (3 times a month on average) and if a fuel pressure concern would depend on how the car is driven.
If the fault is still evident then have a check of the codes done again to see which codes have reoccured to help pinpoint the cause. Out of the 4 codes only 2 would cause a running concern and as I mentioned earlier a glow plug concern would usually be detected more often than a few times a month.
Let me know if I can assist further.
Thanks once again. The saga is it failed a lot last Jul/Aug with garage saying to many codes to make sense of so wiped them. It then only failed 3 times in next 6 weeks with codes being Glow Plugs, Fan Speed & Fuel Pressure, ie 3 different codes for the 3 failures. Codes wiped again. Since then, Oct, has failed 12 times until last Friday, then along with the spills check it was read again & this time there were 4 different codes logged,the same 3 plus Can Bus. As I work with avionics I can't make out why different codes for the same failure. As I said before It only fails when going slow e.g. pulling away from junctions, lights etc.
not all the codes will be for the failure, as I mentioned before the fan control won't affect the engine running, but if there is a cooling fan fault this code will be logged when it has been detected by the PCM on 2 drive cycles. The CAN code isn't relevant as this is set usually with an instrument cluster code and relates to missing information but again it won't cause the problem you have. The glow plug fault can cause the PCM to cut power as it's an emission related fault but only on a stage IV emission engine but I would expect the fault to happen more often if it were this causing the problem.If the engine is a stage III emission then the glow plugs failing would only log a code and not cause any warning message, this is only on stage IV when the glow plugs are monitored as part of the stage IV emissions. All this then comes back to the fuel fault which is the fault I believe is causing the concern and would match the symptoms.
Basically fault codes can be stored in the PCM but they aren't necessarily all related to the running concern but are on systems monitored by the PCM the other codes may have been there before the fuel code but as the engine ran OK you wouldn't be aware of them it's only now there is a running problem you become aware of them.
As I said previously U1900 is a very common code that I see on most Focus but it has no influence on the engine running and so people aren't aware of it been stored until a fault occurs and another code is stored.
Wiping the codes will get rid of them until the car has done 2 drive cycles at which point if any of the faults that caused the codes are still evident the same code will be logged again.
I hope this clarifies things for you, let me know if I can give more information.
Thanks very much for your help it's much appreciated.