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Various problems ..UCH ?

66K views 50 replies 13 participants last post by  Troll 
#1 ·
Hi all

Have started to get various problems with my Laguna 1.9Dci 03 estate.

After doing some research it is pointing to the UCH unit .. and it seems on these forums that as soon as anyone mentions this part no one responds to the thread ? But here goes !!

Does anyone know if this part can be opened and fixed i seem to have various problems on my car all on the passenger side.. So my questions is simple .. there must be a bad connection or dry joint or something in this unit that has failed ?? Anyone had any luck repairing them or replacing them (i know lots of other stuff needs replacing too)

Thanks in advance :confused:

This is a link to another thread i started http://www.renaultforums.co.uk/showthread.php?t=109597&highlight=central+locking - Thanks
 
G
#2 ·
As far as i'm aware, it's basically a mini ecu with a built in loom that can be coded once to a car, and thats it.
As for opening it up, worth a go i suppose! If it's dicking about you'll need a new one anyway
 
#3 ·
hi

they can be repaired, but renault do everything they can to discourage this.

there are a few companies in the uk that do component level repair to them, as they are nothing more than mini computers with masses of I/O lines when looked at, as just about everything electrical on the car runs through them.

i have done component level repair to mine the other month, as i hooked up a wire to the wrong pin and fried/overloaded an I/O buffer.
all parts on them are surface mount, so its deffinatly not a DIY fix, i had ot use a webcam microscope on mine to double check i didnt have any short curcuits on the board after i replaced 2 chips and a resister pull up pack.
i did post a pics of the UCH in a previous post last year.

getting a spare unit as scrap for components is about £25

finding out what the I/O lines into the unit are is a pain as the only data can be found on AutoData garage diagnbostics software (silly money to buy and licence.)
if you can get the printouts then you stand a chance of knowing where to start looking to trace the relavent lines though the fusebox and back onto the UCH. (haveing a friendly garage that doesnt mind you pouring over their autodata program and print-to-file all the relavent pages really helps:d )

a new UCH is £210 from a dealership (vat is probably extra ;p) order time is 10-14 days from france special order (remmber to take all documents with you if you need to order one.)
 
#4 ·
Hi Thanks for the response. :)

Took out the fuse box and UCH ... Managed to find a blown diode and a lot of dampness .. picked a coupe of fuse boxes this morning from local scrap yard one from a diesel and one from a petrol .. will try replacing this before moving to the UCH ..

Thanks will post back :cool:
 
#5 ·
hi, having simular problems with my 03 clio 1.2 16v, intermitent windows, indicators, wipers and sometimes wont start, but it all has one thing in common - a rapid clicking noise coming from the uch, sounds like the click of as relay but lots of times repeated, i'm not really interested in going inside the uch, a bit out of my league i'm afraid, if i bought a new or second hand one, can i change it myself?
cheers
 
#6 · (Edited)
The UCH needs to be changed a matching set of ECU, UCH and Keycards (from a same/similar spec/same engine car) if you're not able to get a Renault dealer to program a unit...

I spent today disassembling and cleaning the fusebox and UCH in mine. I found a fair amount of corrosion and there has obviously been quite significant water ingress. However, things that I know run off the UCH work fine on my car so I don't think it's responsible for the faults. Also, things that don't run through the UCH aren't working right, so I suspect a loom/earthing fault. The UCH only had a bit of corrosion on the pins, whereas the fusebox was dreadful inside, so I might try replacing it. I also cleaned the connections on the fusebox behind the glove compartment, which was in a similar state (I'm guessing sunroof drains, but I pressure washed it today and didn't find any dampness in there, so I guess they've since been sorted.) Does anybody know whereabouts in the front footwells the earthing points are? (I know roughly where all of them are from the Haynes manual, but it's not very specific...)

I'd love to be able to afford a CLIP interface... :( I guess it's capable of testing/diagnosing UCH functionality.
 
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#8 ·
just make sure side lights are on, when u pull the battery connection.
shouldnt be any risk once car is electrically dead to rip out all those sensitive modules.
 
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#11 ·
I believe that the uch among other things controls the immobiliser. It checks that the key or card is paired to the car if the key passes this test it sends a coded message down a data wire to the ECU. If the ecu is happy with the information provided by the uch it releases the immobiliser functions. These are normally fuel pump ignition etc, this means as already been stated the key/card, UCH and ECU all have to agree that everything is OK and are matched to each other. It is possible to change a single component but usually means a recoding job with diagnostic equipment. Its to stop 'toe rags' hot wiring your car and giving the police a load of grief lol.
 
#12 ·
so if i found one from a car of my age, with same engine etc.. there's a possibility it might work?
if not, could a regular garage sort it? or would it be a renault jobby?

i also see on ebay that some people selling the uch also include the key! why is this?
cheers
 
#13 ·
I believe you need to replace the keys, uch and ech from the same car as the one you have and they have to be matched ie all of the same working car. Then I think its a replacement job otherwise the components will have to be recoded to match them up to each other. This requires sophisticated diagnostic equipment and knowledge, if you buy off ebay there is a risk that they are not from the same working car! Also the fault may not necessarily be in one of the three components replaced! I see in your original post you have random intermitant electrical faults, not sure about your particular model but there have been problems with water damage contamination. It might be worth getting the uch out and look for any signs of water!
 
#20 ·
It could be argued that your two front windows are two functions, not one. And that then changes the focus to some other common mode failure that might affect both functions. (Damage to just these two parts of the UCH is unlikely, without something expressly causing it, as the actual circuitry would have nothing else in common)
Do your rear windows still work?
Anything else that relies on ignition, etc? Like the speed of internal light dimming?

If you get other (internal) functions to work, then the power and ignition signals are reaching the UCH, and you might then need to check the fuses and power at each stage down-stream. (Not forgetting issues at the control buttons, which might be focussed on the driver's door, where the two systems also converge. Or even the harness for the driver's door, with it's convenient connector in the exposed area near the hinge).

I'm still hypothesising about system diagrams, but most of the relevant issues are either obvious (like switches, motors and fuses) or assumed good (like harnesses, bonding paths, and lack of corrosion in the UCH). Fortunately, most electronics nowadays can survive disconnecting the load (broken wire) without frying the driver. (That's the power driver circuit, not the nut behind the wheel ;) )
 
#19 ·
I'm having problems with the rear wipers and front foglights on my 2001 Clio. My local garage said that this is probably the UCH and that they couldn't replace it as it would need to be programmed. My local Renault garage has just quoted to replace and re-program would cost in the region of £500! Will learn to live without the rear wiper and front foglights!:eek:

Jassyblue
 
#21 ·
Hi tolak, my driver's side switch was failing in that the buttons weren't as good as they used to be and some lights had gone, so I've bought a new one off ebay and will see if - miracle - that fixes it. On my BM there is a control module in the drivers' kick panel for the central locking which runs power to the door and back for heated locks if fitted. It fails at the door hinge stopped the CL from working, so you just rejoin the wire inside the kick panel bypassing the door completely and all sorted. I'll check for any visible damage when I refit the switch.

Otherwise, damage to the UCH would be from water ingress, though I've not had it out to check,

Cheers!

:d
 
#22 ·
Hi tolak, my driver's side switch was failing in that the buttons weren't as good as they used to be and some lights had gone, so I've bought a new one off ebay and will see if - miracle - that fixes it.
Obvious, really, but ensure that the new switch is the same colour as the old switch. (That's the colour of the connector, not the bit you touch). For example, if you fit a one-touch switch where the function is not supported (eg brown switch to white connector) you will blow the fuse F29 on the second fuse panel.
 
#31 ·
Guys,

Just read through all of this and im looking toward the UCH as i have problems with my wipers.

Ive now gotten to the point where as soon as i plug my wiper motor in they go! and wont stop.

When i use the wiper stalk nothing happens and i can only hear a relay when i switch it onto the highest setting.

Would this point towards 1 or 2 relays (different speeds) being faulty or something totally different?

Thanks
 
#33 ·
Update: front windows started working again then stopped, now rears have stopped. Guess I could try another driver's switch replacement but still wondering if it's the UCH...? Everything else works ok just the windows. Couldn't be all fuses / motors / switches, must be a single point of failure somewhere? Thinking new UCH and Indy replace or bba reman?

Cheers!
:d
 
#34 ·
I've got a static immobiliser light, no response from the steering lock at all. I've had the ECU, UCH and steering lock out. The UCH has water damage on at least 3 chips I've sprayed electrical cleaner on them. The main fuse board has been cleaned and fuses cleaned. Both main junction connectors have been cleaned. There was water ingress on the passenger side, due to blockage in the wings under the wiper scuttle. There is the usual rust on the mounts under the dash. (Why do all renault have this?? This is my 5th laguna. Even the Masters have the same issue). I don't want to scrap it as I'd only get £150. Parting out is a waste if time.
Any ideas next. I was going down oute of refurb steering lock, then UCH but where does the UCH refurb?
 
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