Hi,

Began having an intermittent electrical problem with my 2009 Focus 1.8 TDCI which first started happening in the week between Christmas and New Year.

The car started flashing like a Christmas tree, immobiliser light flashing constantly, engine malfunction, power steering malfunction, reduced acceleration, mileage and range went blank started showing dashes.

Restarted the car a few times then the issues disappeared and the car ran fine as normal no engine lights etc.

Continued to run fine until a few days later when it happened again but this time after an hour journey and then being parked for around an hour and a half. Same thing again, flashing immobiliser, engine malfunction, reduced acceleration. This time the engine light came on along with the abs light. The ABS light went out but the engine light stayed on.

I have a cheap obd reader from Amazon so plugged it in and got the codes - U0140 and U0155.

Used the car the next day for a 15 minute journey, light still on but when I got back in it to come home the engine light had gone out and all fine as normal?

I started thinking is it the cluster? But it hasn’t ever gone completely blank on me but I do have feint vertical lines going through the LCD but it has been that way for a few years and never had any issues. Gave it a tap when this happened the second time but didn’t make any difference so thinking it isn’t that.

It starts first time on the dot each time without issue. Battery is around 3 years old now but is a good quality Bosch. The car is not used that often in the week as I work from home the majority of the time. Which I can imagine does not help things especially this time of the year. 

Im going to look at getting the battery tested to see how that looks, but I’ve also been told that the earth points can cause problems like this too? Can anyone give me a good indication of where to start please? 

Any help appreciated thank you.

 

Guaranteed to be the cluster.

If you use FORScan to read the codes you'll find there's a lot more

Contact @rd457 on here to get it sorted

7 hours ago, STBlues said:

I started thinking is it the cluster? But it hasn’t ever gone completely blank on me but I do have feint vertical lines going through the LCD but it has been that way for a few years and never had any issues. Gave it a tap when this happened the second time but didn’t make any difference so thinking it isn’t that.

Tapping won't always make a difference. If bashing the dash above makes it behave itself, that's positive confirmation. If it doesn't, that means nothing.

Pretty much guaranteed this is going to be the classic IC cracked solder joint issue that I repair: https://www.ebay.co.uk/itm/314393033915

Vertical lines on the LCD are quite common. That'll probably go away with a replacement LCD (It's rare I get to do an LCD replacement so I can't remember for certain). I'd love to sell you one, but replacements aren't cheap so you probably wouldn't want to bother with it.

23 hours ago, DaveT70 said:

Guaranteed to be the cluster.

If you use FORScan to read the codes you'll find there's a lot more

Contact @rd457 on here to get it sorted

Thanks Dave, I might look at installing FORScan and ordering a suitable OBD reader for it to connect with laptop firstly to see whatever else pops up for me. 

20 hours ago, rd457 said:

Tapping won't always make a difference. If bashing the dash above makes it behave itself, that's positive confirmation. If it doesn't, that means nothing.

Pretty much guaranteed this is going to be the classic IC cracked solder joint issue that I repair: https://www.ebay.co.uk/itm/314393033915

Vertical lines on the LCD are quite common. That'll probably go away with a replacement LCD (It's rare I get to do an LCD replacement so I can't remember for certain). I'd love to sell you one, but replacements aren't cheap so you probably wouldn't want to bother with it.

Thanks rd457, that’s really handy to know. I have saved your eBay page link, going to get forscan setup on my laptop to see what else I can get out of it firstly. Then will look to send off to yourself for repairs thanks for the help!

1 hour ago, STBlues said:

Thanks Dave, I might look at installing FORScan and ordering a suitable OBD reader for it to connect with laptop firstly to see whatever else pops up for me. 

Once you get sorted (don't be tempted to buy a cheap lead with the switch on) if you find loads more "U" communication issues and, more importantly, "THEFT DETECTED" then it's definitely the cluster

Get either the recommended V-Linker or the OBDLink-EX cables

FORScan

On 4/7/2024 at 8:59 PM, unofix said:

FORScan (for use with Windows Laptop) : https://forscan.org/download.html

It's what many Ford owners use including some Ford technicians.

• vLinker FS, cable for laptop: https://www.amazon.co.uk/Vgate-vLinker-Adapter-FORScan-MS-CAN/dp/B0952P4MLP

OR

• OBDLINK EX, cable for laptop: https://www.amazon.co.uk/OBDLINK-EX-FORScan-OBD-Adapter/dp/B081VQVD3F/ref=sr_1_5

For diagnostic use only:

• vLinker FD, for android phone: https://www.amazon.co.uk/Vgate-Bluetooth-vLinker-Scanner-Diagnostic/dp/B08H82WC8L
• vLinker FD+, for iPhone: https://www.amazon.co.uk/Vgate-Bluetooth-vLinker-Scanner-Diagnostic/dp/B08H8JHWP2

 

On 1/15/2026 at 2:19 PM, DaveT70 said:

Once you get sorted (don't be tempted to buy a cheap lead with the switch on) if you find loads more "U" communication issues and, more importantly, "THEFT DETECTED" then it's definitely the cluster

Get either the recommended V-Linker or the OBDLink-EX cables

 

22 hours ago, unofix said:

FORScan

 

I managed to get the v linker reader delivered today. Setup forscan last night and installed the drivers for the reader successfully. 
 

Plugged the reader in and got quite a few codes in return. Does this still point towards the cluster being the main culprit? Or wondering if it could be a battery or alternator  problem.

Going to get the battery tested to check that firstly as didn’t have time on my lunch break to do a live test of the load on it. But the voltage to the modules is dipping more which explains the problems especially when I have everything on I.e lights, fans, radio etc. 

 

The voltages on the second picture, are they with the engine running ?

You need to check the resistance of the MS and HS Canbus systems.

2 minutes ago, unofix said:

The voltages on the second picture, are they with the engine running ?

You need to check the resistance of the MS and HS Canbus systems.

No I only had a small amount of time on my break to quickly pop out and plug it in whilst checking the codes. Going to plug it back in tomorrow to check the voltage with the engine running before I take it for a run. 

Can I check that specifically with forscan? Or will that require a multimeter? Sorry I’m not the most mechanically minded person but trying to get to grips with things.  

Thanks for the answer.

So firstly I would say that your battery State Of Charge (SOC) is very low. It needs the minimum of a 12 hour charge (longer if possible). Do not take it off charge just because the battery charger is saying it's 'full'

You should use a multimeter to measure the battery SOC about one hour after the vehicle is parked. See the attached table below.

FORScan can be set up to show live data including the SOC, the vehicle charging voltage, the battery charging current etc. (see second table)

On 1/15/2026 at 6:14 PM, unofix said:

You need to use a multimeter and measure the resistance of both MS and HS canbus systems at the OBDII port.

Each Canbus should measure 60 Ohms.

 

 

12 minutes ago, unofix said:

Thanks for the answer.

So firstly I would say that your battery State Of Charge (SOC) is very low. It needs the minimum of a 12 hour charge (longer if possible). Do not take it off charge just because the battery charger is saying it's 'full'

You should use a multimeter to measure the battery SOC about one hour after the vehicle is parked. See the attached table below.

FORScan can be set up to show live data including the SOC, the vehicle charging voltage, the battery charging current etc. (see second table)

Thank you for your help with this, really appreciate it. Will look into that next, hoping it is just the battery being low. Doesn’t help things that I do not use it every day coupled with the cold weather. 

On 1/16/2026 at 9:07 PM, unofix said:

  On 1/15/2026 at 6:14 PM, unofix said:

You need to use a multimeter and measure the resistance of both MS and HS canbus systems at the OBDII port.

 

Apologies for delay in response on this. I have picked up a multimeter today and just tested the obd port.

The HS canbus is reading 120 ohms! MS is healthy at 61 so going to book in with rd457 who helpfully provided a link to book in for repair.

On 1/14/2026 at 5:05 PM, rd457 said:

Tapping won't always make a difference. If bashing the dash above makes it behave itself, that's positive confirmation. If it doesn't, that means nothing.

Pretty much guaranteed this is going to be the classic IC cracked solder joint issue that I repair: https://www.ebay.co.uk/itm/314393033915

Vertical lines on the LCD are quite common. That'll probably go away with a replacement LCD (It's rare I get to do an LCD replacement so I can't remember for certain). I'd love to sell you one, but replacements aren't cheap so you probably wouldn't want to bother with it.