siamblue has now contacted me, apologies everyone for the brief thread hijack :)

PS back on topic, my local friendly auto electrician reckons he can reprogram the 2002 CEMs (if for example I got an S40 CEM that didn't have rear wash/wipe function). Which means if he can do it, others can too. Unless he's talking bullshine of course and he can't really do it....

Hi
What would be the relay for the winshield wipers, just got a V40 and the wipers stop in the position were you switch them off.
Thanks

Thank you to all involved in this thread.

I brought a 2003 V40 1.9D 2 weeks ago with what I thought was a blown near side dipped beam bulb.

Tried changing it to no avail. Pulled out headlight etc to check wiring but all was fine.

Quick google search brought up a few things but in particular this.

Managed to get 2 new relays this am from RS as per link on earlier page, fitted them both (N/S and O/S save doing it again later) and now working like a treat.

Out of curiousity (and after making sure new ones worked), I stripped the 2 old relays to see if there was a difference. The result is the faulty 1 has a dirty/ burnt out contact as per picture;

Faulty N/S relay on the left, Working O/S on the right;

http://i162.photobucket.com/albums/t...20511-1610.jpg

How did we survive without the internet? :)

Thanks again all and I look forward to being a more active member on this friendly forum.

Chris.

fog light and parking light
 

i have similiar problem in that front and rear fog lamps and the dash tell tales dont work neither do front and rear parking lights or switch illumination help! 2002 s40 diesel sport im thinking cem packing up

This is a really good thread:thumbs_up:

Dodgy CEM
 

Hi all,
I have an 02 S40 1.9D Sport. Had a similar problem, n/s dipped beam not working. Bought "fully tested" replacement CEM from Ebay. Fitted and now have n/s dipped beam but no main beams in any of the switch positions. Refitted original CEM and main beams returned. Contacted seller, who says CEM needs to be reprogrammed! Other contributors to this forum have bought CEM's from scrappies and not had to do this.

Have I been conned or just unlucky? Surely whatever car it is from, the main beams should work?

Can I just swap the n/s dipped beam relay to my old CEM?:lightbulb:

Thank you
 

Long time lurker, first time poster. Just finished replacing the faulty relay in the CEM of my 03 S40 and had to offer my appreciation to this thread. With literally zero PCB/solder skills, was able to replace my relay and resolve my right headlight issue within an hour start to finish. $7 with shipping sure beats the Volvo quote (over $1200) or the used option on eBay ($150).

Thanks all! Cheers-

Dodgy CEM again
 

Any ideas?

It is a programmable feature that can be done by anyone with DICE. However, I find it really hard to believe that someone programmed the CEM disabling the main beams

corroded wiring loom under the radiator :lightbulb:

Thanks Gatos, my feelings exactly! Why would anyone disable main beams?
don't think the wiring loom under the rad is at fault, main beams work on my original CEM.

Just discovered CEM is from a 01 V40, is this a problem?

No it shouldn't be a problem. THe only difference between the S40 adn V40 is that the V40 CEM is programmed for the rear wiper. However I have tested and confirm that with VIDA and DICE, you can program an S40 CEM to utilise the rear wiper as well as enable/disable the fog lights and some other functions.

Tell the buyed you want to return this CEM and that you want your money back. The description of the item was incorrect. Even if what he says is true, then Volvo would charge you a fortune to reprogram it. I also have a CEM in case you still need one. I have tested it on my own car and everything works as it should.

Many thanks Gatos, you have confirmed my suspicions and also answered my next question, i.e cost of reprogramming. I will return the unit and demand a refund. I would like to buy your spare CEM, how much do you want for it?

I normally sell them at £30 plus postage. However, in case it does not solve your problem, then you can of course return it back with no questions asked.

I will also need you to confirm what your car has on it, so I can program the relevant values. In your case, you have a 2002 S40 1.9D, so rear wiper is out of the question. However, I need to know if you have front fogs or not. Or I can program it with fogs in case you don'ts have any and would like to add them in the future.

That's great, Gatos.
Please program it for front fogs, I dont have them but would like to fit them,
are they difficult to fit? do you happen to have a set?
Can you take payment via PayPal? if not I can post you a sterling cheque.:thumbs_up:

They are fairly easy to fit I guess. I have them on my car, but I hardly ever use them and find them pretty useless.... lol. But a lot of people like them. Paypal is fine.

I don't have a set of fogs, but Siamblue has one, so you can ask him. He leaves down the road from me, so he can drop them at my place and I can send everything together.

You will also need the headlight switch with the fog lights buttons on it, in which case, I have it for a tenner

Hi,

I'm new here, I got the problem with my dipped head light on both sides, just one day before the scheduled service... good timing...
it is a v40, 2003.
when i took the car to service, the dealer just said this was because of replay in the cem box need to be replaced. Based on there was no voltage on the headlight socket, the fuse in the fuse box was ok. If I replace the new cem box, costs more than 4000 sek... Sorry forgot to mention I'm in Sweden.
So I took the car home, opened the cem box with the wires on and test with voltmeter. Please help me to see if the replay is working. Because I'm so lost and give the basic physics to my teacher :-P

when the key is off,
the voltage between com and NO is 12.15 on both sides

when the key is on
and light switch on
the voltage between com and NO is 11.90 on both sides.

Are these relay working? or the contact got oxidized? Thanks!

Thanks Guys!!
 

:thumbs_up:Problem finally sorted, new CEM from Gatos works fine. Thanks to Gatos and SiamBlue for all your help.:star:

Lesson learned, beware of "fully tested " spares from FleaBay! Dodgy CEM returned for refund. I will source all my spares on this forum in future.

Does anyone know, which of this is the front and rear sidelights (parking lights) relay?

CEM headlight issue
 

hi all the cem I changed my headlight worked immediately done so simple its a joke all tools requited a philips screwdriver
done
thanks to you all this thread really did the biz for me awesome

CEM headlight issue
 

Guy's I brought my CEM from Ebay working no issues
cost and this is true £5.00 post £0.99 for the item
total £5.99
right chuffed

Well done, I got £40 for mine! Took a while to sell though

With one dim dip headlight down, I replaced both dim dipped relays on the CEM with RS Component's part number 2172876 at a cost of less than €10, got a friend to solder them in and it worked a treat! Thanks once again to all who posted to this thread and others.

How do you take the old relay out? and how do you replace it with another?

You will need a soldering/de-soldering iron. If you have never soldiered before it's not the easiest job to do

Hi all and thanks for the info Russell. I too have a suspected CEM problem but I'm unable to track down a replacement for this particular part number (30621304) which appears to be for the LHD version and the only ones I can find are in America.

I'm beginning to wonder if I have the correct CEM in place and would be grateful if anyone can confirm the part number. My car is a 2002 V40 1.9D S, registration number WK02 MZX.

I changed the bulbs and can confirm the new ones are working (tried a different CEM that I thought might work 30858700) but it left the lights on all the time and a meter read at the fuses is showing no power.

Many thanks in advance

Depends what your Chassis number is. Check the last 6 numbers on your VIN.

See here:
Control unit [-2001, L.H.D (30859699)] 30896697
Electronics box [2002-, L.H.D (30621304)] 30638707
Control unit [-2001, R.H.D (30859700)] 30896698
Electronics box [CH 800000-026445, R.H.D] 30621305
Electronics box [CH 026446-, R.H.D] 30638708

Yours will either be the 30621305 or the 30638708

I think I have both in case you want one and I can enable/disable the fogs, rear wiper etc

I am 99 % sure that only difference between LHD and RHD version is in housing - position of mounting tabs.

I think so too.

is your car a LHD ? I have a feeling it may be an import ... and not visited a volvo garage over here ..

Fog Relays
 

I noticed on Russell_s original post, the wiring diagram shows the fog wiring as well. My V40 does not have the fogs, can I simply unsolder the relay for the fogs and place it in the faulty dip's place leaving the fog relay location blank? If so what of the relay numbers is the fog relay? (There are 6 identical relays on my board. Russell_s photo shows 4, an obvious difference in year or country) I'm assuming RLY1 or RLY2.
Thanks for any help you can toss my way.

Hi,
Just want to thanks for this great thread! My right headlight didn't worked for a couple of months now and the fog light (and switch) I installed this summer, I coudn't managed to have them work... Visited 2 dealers and no answer on solution... (I have a V40 2002)
After reading this, I got a used CEM from a V40 2004 with fog, just swap with mine and headlight and fog turn on!!!
I'm a happy man!
Many thanks

CEM for 03 V40
 

Would you by any chance have a CEM for sale for 03 V40? No dipped headlamps but full beams work OK.

Can you check the part number on it and let me know so I can check the ones I have? It should be 8 digits long and starting with 306 or 308. Are you sure it is your CEM that is at fault?

Pretty sure it's the CEM, local auto-electrician diagnosed problem back to the CEM. Same thing happened a couple of years ago, no dipped headlights and volvo quoted €500+ for the part. Eventually got one in a breakers yard although it was on an S40 as not so many V40s sold over here. Although Volvo parts claimed that it was an unusual fault when I rang around beakers yard lots of the CEMs were missing! Part no. I have is 30621305 which is the one from the S40, unfortunately I dumped the original. By the way, great forum.

As far as I am aware of, the part numbers don't differ between the S40 and the V40. The only difference on the V40 is the presense of the rear wiper which the S40 does not have. The only difference I have found out todate between the different part numbers of CEMs is the operation of the high beam. If a different CEM is used, then the high beams will not stay on when you pull and release the indicator stalk. There seems to be a link between stalks and CEMs. I definitely have a 30621305 so if yours was working fine all this time then my one should not be a problem.I will program the rear wiper and test all the functions of the CEM on my car to make sure it is fine. I will PM you my email so you can contact me.

Got the CEM and my headlamps now work perfectly. Thanks a million.

Thanks for letting me know. Hope this one lasts you for some time. Also, if you decide in the future to add fog lights, they will just be plug and play:).

Hello people! I am glad to have found this forum because you seem to be just the person who can maybe help me.

I've been driving around with a 2001 V40 for about a year now, with the rear wiper dead. The volvo dealer first thought the motor was broken, but after further diagnostics they blame the CEM (at a mind blowing cost of course).

From what I've read it looks like a CEM is fairly straightforward to replace with a second hand one. But I don't understand the 'programming' bit fully. Is the programming unique for every car? Is there a wrong CEM I can buy for a V40? You said you have some lying around. What would be your price?

thanks for reading!
best regards,
Zev

Hi Zev and welcome to the forum. When I use the term "programming, it may sound more complicated than it really is. What it really means, is that you can enable/disable a few options with the click of a mouse. See attachment.

The following components and functions can be activated:

The following can be programmed:

• Automatic low beam
• Twin headlamps
• Front fog lamps.
• Tailgate wiper
• Tailgate wiper when reversing.

There are a few different CEMs out there as they have changed something over the years. They are not car specific and you can easily swap them from one car to another. Here are the different models listed in VIDA:

Control unit [-2001, L.H.D (30859699)] 30896697
Electronics box [2002-, L.H.D (30621304)] 30638707
Control unit [-2001, R.H.D (30859700)] 30896698
Electronics box [CH 800000-026445, R.H.D] 30621305
Electronics box [CH 026446-, R.H.D] 30638708

Ideally you should try to replace the CEM with another one with the same part number. Saying that, I have tried a late 2000 CEM on a 2003 car and it worked fine. Only issue I am aware off, is that if you mismatch some CEMs, then the high beams are in "soft touch mode", meaning that when you click the indicator stalk backwards for the High beams, they don't stay on unless if you hold the stalk towards you.

Anyway, back to your problem. It is possible that the previous owner swapped a CEM taken from an S40, which has no rear wiper by default. In this case Volvo should be able to program it in less than 5 minutes. Or, it is possible that your CEM has developed a fault and it needs replacing.