207 ABS woes

[Nuneatonrob]

Hi folks,

Hope somebody on her can help me out. My brother in law has a 207 which has been a nightmare recently. It's just had a replacement engine due to the head gasket going on the old one and severely warping the head, and now the ABS block has died.

The symptoms were a message saying brake system fault or similar, then abs light on, power steering light came on, power steering died, mileage read out on dash came up ------- and the speedo died and went into limp home mode.

Anyway, seems this is a fairly common problem on early cars, this one being a 07 plate, 1.4 16v S.

The abs block has been sent off to a company for checking and it's come back as completely dead, they can't fix it. So what we are desperate to know is whether or not a ABS block with a slightly different model number is comparable? I can find loads on eBay but not one with the exact same numbers on it.

For reference the numbers in the cars original broken unit is 9662298480 10.0207 -0092.4 on the block and 3TU7B126M9 10.0970-1144.3 00404858E0 on the controller.....

This car has so far been off the road longer than on it this year, so I'm really hoping somebody can help.

Thanks in advance.

Rob

[Lighty]

Think you will need a new one, the numbers are different for a reason, think a new computer is about £300 to £400 , surely this is better than the car being off the road.

[uncle buck]

Hi,
don't know if this will help or not but I can tell you that there are a few people that have changed the ABS unit on Renault Lagunas with no problems, I'm sure some of them used different numbered units, actually some of them only changed the ECU part as this is the part that normally fails.

I changed the full unit on my car when I had an ABS light problem, but the 2nd hand one was the same number as the original.

Depending on the price of a 2nd hand unit you could take a gamble and try one with a different number.

What make is the ABS unit, is it ATE?.....can you post a picture of it just so I can see what it looks like.


Cheers.

[Nuneatonrob]

The main problem with these units is it needs to be coded to the car by a dealer or somebody with the appropriate diag kit. I think this will cost somewhere in the region of £80 to £90 and the replacement unit varies from £60 to £140ish second hand.

Cost is the overriding factor at the moment, fortunately there's a van that can be used in place of the car, but obviously getting the car on the road ASAP would be useful, but as cost effectively as possible.

The unit ate

Thanks for the replies so far.

Rob

[uncle buck]

Are you sure it needs coding to the car, how do you know this?

I must admit I didn't think I was going to be able to just fit a 2nd hand ABS unit to my Laguna without having to have it plugged in but it worked and as I say others have done the same.

The reason I asked if it was an ATE made unit is because that's the same make as what the Lagunas use.

Now here's a bit of a story for you and a few pictures....

Once I removed my old ABS unit I took it to bits, I've read that the problems come from the ECU part of the unit, this part is replaceable on it's own, figuring I had nothing to loose I cut open the ECU to see what was inside.

I found that the pins on the circuit board are a push fit pin, they aren't soldered they are just pushed into a hole and this makes the contact. This technology is now being used on lots of things. The pin has a head on it like the eye of a needle so in theory when it is pushed into the solder lined hole on the circuit board it makes a nice tight contact.
I'll not rabbit on about it but I've researched this push fit technology & I can tell you that there are people in the industry saying that it's not as reliable as the manufactures would have you believe.

Why am I telling you this...well if you're up for a challenge and the old ABS ECU is just going to get thrown out it may be worthwhile cutting the lid off of it to see if your ECU has the push fit pins also (Very likely) if it has you could solder them all as I have a feeling that the units are failing because of bad joint on the circuit boards, I would love to be able to tell you that it will work but I haven't actually tried my soldered ECU back on my car yet.
I did solder each pin / joint on my ECU but as the ABS unit is mounted behind the front bumper in the N/S wheel arch it means that the front bumper has to be removed to get to it and I just haven't had the time to try it, I will try it at some point as I would like to know if my thinking on this is correct.

So if you fancy having a go at it and posibly fixing your problem and also proving my theory, I'll give you as much advice as I can.


Cheers.



Here's some pictures for you.

The ABS unit, The Motor, Valve block, & ECU.




Inside the ECU showing the push fit pins




Close up of push fit pins




Showing the soldered pins

[Nuneatonrob]

Thanks for the reply Uncle Buck. That's a great help.

The original unit was sent off to a company called ecu testing, and they returned it saying that it was completely fried and unrepairable, however, we've nothing to lose by taking it apart and soldering the pins on any push fit chips and giving it a go. On the 207 the unit sits in the front passenger wheel well, and is accessible by simply removing the the wheel and splash guard.

Of course if this method doesn't work, then the alternative is to obtain another unit from a donor car and just try it.

It was a couple of things I read on the internet that said the unit had to be coded to the car, but why this is I've no idea. It's just a bit of a gamble as most of the time electrical components cannot be exchanged....

Cheers,

Rob

[uncle buck]

Hi,
Like I said in my previous post I have no idea if soldering the pins will work as I haven't tried my soldered ECU back on the car yet, I may be barking up the wrong tree completely but I just have a feeling that these solder less pin connections are causing problems.

The way I see it if you have nothing to loose you could give it a try, it may or may not work, you may waste a couple of hours of your time on it only to find that Uncle Buck was talking rubbish... who knows.

I know that the ECU part of the ABS unit is available separately, so for example if you took the car to the dealers to have it fixed they may just fit a new ECU, maybe then the ECU would have to be coded to the car, once again I'm only guessing here going from my experience with my Laguna, someone who knows more than me may be able to tell us if a 2nd hand ECU would need coding.

My ABS problem on the Laguna started as an intermittent problem, the ABS light would come on for a day or two then it would go off for maybe a week or so, this looked to me like a dodgy connection. I had my car plugged in at a Renault specialist using a Renault Can Clip, this couldn't communicate with the ABS ECU so obviously there was a broken connection somewhere, I got a 2nd hand unit bolted it on and it fixed the problem.

With the old ECU heading for the bin I decided to cut it open to take a look, when I saw the push fit pins I didn't know what they were, I researched them and that's when I got to thinking that maybe the pins were the reason that the ECU had failed.

There are videos on you tube of people repairing ABS ECU's but most of these are on older type ECU's that do have soldered connections, just about all of the faults are cracked solder joints that are repaired with a few dabs of the soldering iron.

If you solder the pins and it doesn't work you will have to get a 2nd hand ECU from somewhere, I would try to get one if you can that has the same numbers but then again I'm not sure if this make that much difference. I know with the Laguna some cars had Electronic Stability Control, I think the ABS ECU will control this, so I would imagine a car that has this will have a diffrent ABS ECU than a car that doesn't have it.

Cheers.

[uncle buck]

Anything happening on this Rob ?

[Nuneatonrob]

Wow it's been some time. Nothing has happened with this since I last communicated. I have only just got the block and ecu from my bro in law to have a play with. Renovating a house and work commitments etc etc etc have just got in the way and the car has just sat there growing moss on it for all this time.

Going to try and resurrect this and have a go very soon. I'll let you know

Rob