advertisement


How easy is ECU replacement on a 2009 Ford Focus?

Sean K

Sean K

pfm Member
My son is looking at a 2009 1.6L.

The seller has posted an inspection report saying the ECU needs relacing as it's causing multiple error messages but that the car otherwise runs fine.

It looks easy enough to source an affordable used one.

I'm handy with most things but wondering if anything rather than remove and replace is needed or whether it would need hooking up to computer with CANBUS, reprogramming, etc?

Cheers
 
I would have a very good look at VIN and engine numbers, followed by a careful check for cut and shut welding
 
I and another guy at work had the same issue on our Focus' of the same age. It is almost certainly the dash display itself, caused by dry solder on the display and can be repaired by an auto electrician. Cost me £200 or so but would have been a little cheaper if the central fault/info module* didn't have to be replaced.
* The red lit central part of the display unit.
If you phone around your local sparkys, someone will have encountered it as it is a common fault on that vintage of Ford cars.
 
Sean K said:
My son is looking at a 2009 1.6L.

The seller has posted an inspection report saying the ECU needs relacing as it's causing multiple error messages but that the car otherwise runs fine.

It looks easy enough to source an affordable used one.

I'm handy with most things but wondering if anything rather than remove and replace is needed or whether it would need hooking up to computer with CANBUS, reprogramming, etc?

Cheers
Click to expand...
There could be many ECUs on a Ford Focus of this age........which one needs replacing?
 
I would agree a price for the car with the ECU fixed and suggest the seller gets the job done upon which you will pay the agreed price. It could well not be as simple as 'the ECU needs replacing'.
 
On a 1987 Porsche 911 I had terrible misfires and non-starting, and was told by the official Porsche service centre in Rome (who have an amazing reputation for both incompetence and thievery) that my ECU needed replacing. "I think, Sir, that we may just be able to find you one second-hand for about 1000 Euro."
It turned out to be a cracked/dry solder joint on a wire leading to or from the ECU under the passenger seat. It took a while to track down, but was mended for peanuts.
There was a place in Rome, so probably one round your way, where I took the ECU and they put it on the bench and checked that there was nothing wrong with it.
Service centres love changing your ECU, but if the car runs fine maybe it is, as already suggested, a problem somewhere else.
 
OP,

How much do similar cars go for with no suspected ECU faults? I doubt it’s worth the risk.
 
I would avoid completely. It could be something simple, as others have said, or you could be getting into a whole world of pain. Very often, ECUs and keys, plus most other electronics in cars, are linked (e.g. on Volvos you can't swap a factory stereo between cars, as they are coded to the ECU. Even indicator modules are).
 
Multiple error codes are more likely to be caused by dry solder joints in the main binnacle board. This can be fixed relatively easily. This will usually manifest itself by the display cycling through different codes and different codes randomly flicking up and some bits of the display occasionally blanking.

When bits of an ECU fail, you generally get more fundamental issues like cylinders failing to fire and the car will probably be undrivable. Fixing this on an older car would usually involve finding a donor car and transplanting the ECU and all the ancillary components tied to it (ICE, immobiliser etc.). You may also need a quick trip to a main dealer to clear any erroneous codes and get it out of limp mode if your mechanic's kit can't identify them. It is not a trivial job and there is no guarantee the replacement ECU, which will most likely be of similar vintage, will fail shortly afterwards.

If I needed a car like this and I could get it really, really cheap, the rest of the car was otherwise a nice one and I had a good honest independent mechanic, I might consider a gamble on it, but don't take that as encouragement to do so.
 
Yeah - coding of various systems to the ECU in modern cars makes replacement likely to be far from simple. If you are not a car nut who enjoys fixing cars - I would run away from such a proposition. The unknowns have got to heavily outweigh the knowns!
 
Been there..................

Forget any kind of DIY as everything has to be remapped, including to the key. One company who supplied a new unit (for the dash), said it did not - they were wrong.

Resoldering of the dry joints is simple enough, but is unlikely to solve the problems for very long. My hassles were about 6 years ago and from memory, the full work cost me about £500, but I could easily be wrong. Don't go via Ford for a new ECU - that will cost a fortune.

Buying a used unit is false economy as they fail with monotonous regularity, and you have no way to check that it is OK without a lot of work and expense.
 
Several have already said it could just be the instrument wiring

I tend to agree having had this same issue in the past
It's a common issue and a fairly easy fix
There's a flexible "circuit board" on the back of the instruments and the problem could lay there....or on solder joints below this
 
I had this with a Vectra 10 years ago. The indy repairer reported dead ECU, the Vauxhall dealer confirmed it. I found another indy who was prepared to remove it and send it to an ECU repairer in Derby. They reported the ECU as fine following testing and diagnosed a fault elsewhere or maybe even a poor connection. Bizarrely the indy repairer refused to accept this diagnosis and said "either pay us to fit a new ECU or come and take it away". A new ECU was over £1000 and more than the car was worth, so I said "no" and they put it back together. After that it was perfectly fine until the car died about a year later from various unrelated faults.

Would I knowingly go there again? No. You *might* be lucky. A test and repair might be a few hundred. A scrapyard ECU would be more trouble than its worth because it would need recoding to the key etc. and in a lot of these cases an ECU without its original key is locked out and can't be recoded, for obvious security reasons. You might well then be into a £1500 repair.
 
Seeker_UK said:
Yes - it's not like Focuses are difficult to come by.
Click to expand...
You're right, seem easy to get round here anyway, there's a Focus or Fiesta stolen every day cos it takes seconds to take one way with gadgets you can buy on eBay or Amazon. Couple of weeks ago there were 3 stolen in one night and we live in a town of under 50,000 people.

A car thiefs easiest pickings, another reason to avoid ;)

UK top ten most common car thefts 2022

1. Ford Fiesta - 5,724 stolen

2. Land Rover Range Rover - 5,209 stolen

3. Ford Focus - 2,048 stolen

I've no doubt insurance would be affected by those stats too, strangely enough I have a Focus ECU here that I bought for my daughters car years ago, never fitted it, it was easier to get rid of the car once I read up on all the pitfalls with swapping the old one out
 
stevec67 said:
I had this with a Vectra 10 years ago. The indy repairer reported dead ECU, the Vauxhall dealer confirmed it. I found another indy who was prepared to remove it and send it to an ECU repairer in Derby. They reported the ECU as fine following testing and diagnosed a fault elsewhere or maybe even a poor connection. Bizarrely the indy repairer refused to accept this diagnosis and said "either pay us to fit a new ECU or come and take it away". A new ECU was over £1000 and more than the car was worth, so I said "no" and they put it back together. After that it was perfectly fine until the car died about a year later from various unrelated faults.

Would I knowingly go there again? No. You *might* be lucky. A test and repair might be a few hundred. A scrapyard ECU would be more trouble than its worth because it would need recoding to the key etc. and in a lot of these cases an ECU without its original key is locked out and can't be recoded, for obvious security reasons. You might well then be into a £1500 repair.
Click to expand...

If I had a car that developed a fault in one of its ECUs, my first port of call would be to find someone who can repair the unit. If not, I'd bite the bullet and get one from a manufacturer. Buying one from a scrappy is, as you infer, a bit of a lottery. Maybe they have got more standardised nowadays, but I remember trying to get an ECU for Mrs Seeker's Audi cab and, AIUI, there were four or five potential candidates that could be fitted and only one would work. The two I got didn't work and weren't on sale or return so we ended up selling the car with a 'faulty roof'.

I certainly wouldn't buy a car with that as a fault.
 
mikeyb said:
You're right, seem easy to get round here anyway, there's a Focus or Fiesta stolen every day cos it takes seconds to take one way with gadgets you can buy on eBay or Amazon. Couple of weeks ago there were 3 stolen in one night and we live in a town of under 50,000 people.

A car thiefs easiest pickings, another reason to avoid ;)

UK top ten most common car thefts 2022

1. Ford Fiesta - 5,724 stolen

2. Land Rover Range Rover - 5,209 stolen

3. Ford Focus - 2,048 stolen

I've no doubt insurance would be affected by those stats too, strangely enough I have a Focus ECU here that I bought for my daughters car years ago, never fitted it, it was easier to get rid of the car once I read up on all the pitfalls with swapping the old one out
Click to expand...

Bearing in mind that the Fiesta and Focus are the two most popular cars on the road, it is not much of a surprise?

I had a Focus for 14 years, great cars, put 180K on the clock, never got nicked.
 
mikeyb said:
You're right, seem easy to get round here anyway, there's a Focus or Fiesta stolen every day cos it takes seconds to take one way with gadgets you can buy on eBay or Amazon. Couple of weeks ago there were 3 stolen in one night and we live in a town of under 50,000 people.

A car thiefs easiest pickings, another reason to avoid ;)

UK top ten most common car thefts 2022

1. Ford Fiesta - 5,724 stolen

2. Land Rover Range Rover - 5,209 stolen

3. Ford Focus - 2,048 stolen
Click to expand...
How do they steal them? Is it just the modern ones with keyless ignition or are the older ones affected? I ask because my cars over the last 10 years (newest the current 09 Audi) are AFAIK impossible to steal without the key. Even with computer and dealer software, but maybe this has moved on. I do know that post 2000 ish when they introduced the crypto keys car thefts were basically unknown without stealing the keys. Now modern cars with keyless door lockingf are routinely entered, as we've all seen on YT. My neighbour's 2021/2022 Range Rover needs a steering lock when he parks it up; I haven't had to use one of them for nearly 20 years.
 
Last edited:
Jamie said:
I had a Focus for 14 years, great cars, put 180K on the clock, never got nicked.
Click to expand...
I had similar from The Indestructible Mondeo, 160k miles until I got bored of repairing minor faults, and to be fair it was getting a bit ratty by then. I traded it in with no MoT, it went back into circulation and died some months later. A shame, it deserved another year or so.
 
You must log in or register to reply here.


advertisement


Back
Top