Focus 2008, NS front mechanical/electrical problem

[LadFromWales]

I have a 2008 Focus MK2.5 diesel which has developed a knocking/rattling sound around the nearside front wheel. It is very apparent when driving over rough surface, especially at low speed.

I've recently had new tyres fitted at an indie mechanic, who give everything a good shake at the front end and a poke with the pry bar but couldn't find anything amiss. He did find that my offside rear coil has snapped, right at the bottom, and I need need rear trailing arm front bushes, and my discs and pads will need doing soon, but none of these appear to be causing the fault. He was a man down that day so had no time to take it for a spin etc.

The car had a new alternator installed in October, then a week later a new DMF, clutch and cylinder (expensive month!), has done around 2000 miles between then and its last MOT in January without fault. About 300 miles after the MOT this rattle occured. The MOT guy did use a pry bar around the front and rear, but had nothing to say about parts needing replacing.

The knock can occur when accelerating briskly from lower speeds, or when turning towards full lock when parking etc. Took it out for a spin earlier, and noticed that while accelerating, my fans were speeding up, and the ABS/Traction/Battery/Another light were coming on and off. I didn't have my OBD hooked up at the time, stopped and hooked it up and found that when this was happening, the voltage was increasing to around 18.2V! I've read that the Focus smart charge system can increase the output to 18V to restart a dying battery, so I'm wondering if something around the NS front is shorting and pulling the battery down. I didn't use the car for a week, come to use it and the battery was too low to turn it over, had to use a battery pack to get it going. I've had the wheel off, the only wire I can see is the wire to the ABS module, which is seated fine. At other times the voltage lingers around 14.1 to 14.5. While driving, even if it's not knocking, the battery light occasionally comes on for a minute or so, then goes off, and I have noticed the headlights are flickering. The steering wheel also appears to want to sit slightly anti-clockwise by a couple degrees.

Codes pulled state losing communication with the Body Control Module, low voltage, high voltage
P1934 Powertrain
U0140 Network
B1317 Body
C2778 Chassis
P0625 Powertrain
U1900 Network
U2023 Network

It'll be going back in for the discs, pads, rear springs and trailing arm bushes next week, none of which appear to be the cause of this fault, so I am hoping to pinpoint what it could be before it goes back!
The car hasn't been driven a great deal since January, around 500 miles, as work is a few minute walk away now.

Any ideas?

 

[ZG002]

The knock will be a bush, or something along those lines.

As for the other, I'd check your ground and check altanator connections etc. It sounds like your cars losing power, and throwing up warnings etc.

 

[Thebug]

Cv joint?

 

[LadFromWales]

Would any of the above cause an electrical problem at the same time?
Literally as soon as there is clunking from the corner, at the least the battery light will come on, or at most the battery/abs/traction and a blip of voltage to around 18v. The latter can apparently only happen when the engine is cold as the system won't boost the volts like that when the engine is warm. Sometimes the clunking will happen and it'll throw no lights.
There is a curb at a 45 degree angle (parking bay). I have driven towards this, slowly, just so that the NS front wheel meets it but doesn't climb it, which can cause the clunk. When driving it sounds more like a rattle than a clunk. While turning at full lock, or reversing and then going forward (or other way round) it sounds more like a clunk. These slower manoeuvres only throw up the battery light when the clunk occurs.

Cheers

 

[Iamzod]

Your noise & warning lights will be a coincidence, I reckon the noise is either a bottom balljoint or drop link.

I have found garages terrible at diagnosing suspension noises on both of my Mondeos, the last one was a bottom ball joint but I had 2 garages claim it was the ARB bushes which were fine.

 

[ZG002]

Have you checked the alternator connections and mounting bolts?

 

[LadFromWales]

I'll check the alternator connections and mounting bolts tomorrow, as they can be checked easily.
I have been reading up about the lights and have found that the ABS and traction control lights can come on when the computer doesn't get readings from a wheel speed sensor, and the hand brake light comes on also if the computer loses communication entirely with a wheel speed sensor. These lights only flash on briefly so it'd be an intermittent loss of communication.