Repairing BOSCH 4D0 905 351 ICM Unit

Hi all, here the photos about the reparation of the passat ICM. Thanks again Sigi for give me the tips needed!

My little story is that I didnt get spark on the 5th cilinder of my Passat V5, so I thought I could be the coil, fortunately I count find the replacement (by chance I saved 300€), next reading some post like this I thought I could be the ICM, so I decided to measure it, and I had one transistor broke (you need to use a multimeter and a lot of imagination to find the correct disposition), and at the end, I found this post which helped me to think that could be the same problem, and voila!

So I attach the photos I took

1. This image shows the ICM before getting it



2. My brother opened it with a knife (like Sigi's instrucction)



3. Found the problem (a little leg in the air)



4. With a lot of pacience (and 2 attemps) I could join it



5. The final ICM, still working after one month (I touch wood)



Have a nice weekend and thanks a lot again for this kind of post, any dubt just ask me

Jorge

with a sharp knife along the edges it will come off eventually. when you open it try not to tiuch the silicone inside

the wire you have to solder is aluminum so that means it won't solder you have to make e solder ball and place the aluminum wire inside when it cool it won't move that's it

mine still works fine

Click to expand...

Hey SIGI, thanks for you post!!! Thank GOD, I found this post and I fix my part. The dealer here in my country was asking U$ 460.00 + 145.00 Hand Labor[]

I tell them to give me that part that I going to fix it myself. They toll me it was impossible to fix it because is sealed. I tell them, Dont Worry, if I cant Fixed, you put a new one and I will pay the bill.

Open it with a X-Acto knive. The problem was one wire was loose.

Here are some tips. The pin (connector) side is definitely solderable, as is the wire. The secret to the pin side is to remove all the heat sink gel completely from around it.

Then scratch the surface to clean it until it get like a gold color. Then put the soldering iron on. You need to use a hi wattage Soldering Iron. Keep it down for probably at least a minimum of a minute then try to apply solder to the pin. Once the pin takes the solder, move the wire into it.

As for the other side, the FET side, scratch the surface to clean it until it get like a gold color. Then again, apply a lot of heat. Belive or not, with the help of a friend I use two 40 Watts soldering iron and leave it like a minute, then the wire got soldered. After I finish, I push very hard the solder with a small screw driver and it don't move.

Then put black silicone around the edges and put again the plastic cover.

Took the part again to the dealer, I toll them is fixed. The guy was like WTF! Intall it, start the engine and everything was OK. They check it with the computer and everything was OK.

I have been using the car for a week and everything is OK.

They still charge me the 145.00 for the hand labor but WTF, Thats better than pay 460.oo for that part!!!!

Here some Pics:





THX

Sorry for digging up such an old post. also I only registered to say thanks to the OP, as this saved me a bucket full of money. Same issues as described by previous posters, intermittent misfire. Just not sure why it would be intermittent, but I suppose it's as the components heat up and cool down sometimes they make contact other times not.

Cut mine open with a pocket knife and started checking the wires. I have had misfires on 1, 2 and 3 before and as expected all three of those wires came adrift as soon as I gave them a light tug. #4 is solidly planted in place and wouldn't budge.

Scratched all the contacts clean until a copper colour was showing, I suspect it's covered with either aluminium or silver solder, more likely the latter. Put some solder on there and dipped the loose wires into the solder. Car was misfiring this morning, started it to check before doing the fix, was still misfiring and after the fix misfire was gone.

Then Epoxy glued the cover back on after testing.

My specialized engineer on Carburettor, told me that he, very often, has changed this type of ICM. Can you imagine how many people spend 230 € (200 for ICM and 30 for the work, and imagine that my engineer is a cheap one (but good on his job)) ? For, only 10 people, is 2300€ ! That is why, there are rich people and poor. Does anyboby believe that the engineers do not know that this module can be fixed in 30 minutes with almost no cost ?

I did not know what, exactly the problem was (my car went some times, like a tractor) . First i visit my normal engineer. He told me two things

1. Change Sparks 2. Clean injectors.

I went for Sparks but each one costs 10€(normally 16€), but it was not for sure that this replacement would resolve the problem and i did not want to spend 40€ for nothing.

Cleaning the injectors costs 80€. It was much for me, also would not, for sure resolve the problem. I found a solution, how to clean the injectors by myself. It is very easy (if anybody want me to saw how this can happen, let me know) The only problem is that i do not know how to unplug the injectors.(Does anybody know how ?)

So i went to the specialized on Carburettor and injections, engineer and finaly he told me that the problem was the Ignition Control Module. I consider that this information he gave me it was very helpful, because i could now find bymyself a cheaper ICM and replace it by myself avoide to pay 230€, so i gave to him 30€ just for the diagnosis he made (he did not ask for it. I just gave to him)

After this, i read about thermocompound pastas. I read, somewere, that the performance (heat decrease) is better between metals than between metal and any pasta like Arctic. So there is a danger to increase heat, instead decrease it. So now i am in contact with somebody from Arctic's site, to inform me if there is a danger and what is the correct way to apply this pasta.

Then i saw this site and i must tell " thanks God that there is internet !" Thank you SIGI and all other people. I saw the same ICM with mine and the same problem. The only problem was that it was not easy to found it. It happened after 1-2 days of searching.

Because my ICM, sometimes misfires, sometimes not, i decided not to open it wet. I , first, will aplly the pasta, in case the problem caused from the fact that the pasta already existed (if there existed), have dried and there is a malfunction because the current is influenced of the heat increase,(not from a wire brake).

So i will test it and will come again to announce the results hoping my post help other people to save money and avoide "professionals" without

conscience !