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How to: Volvo C30 S40 V50 C70 CEM Removal and Cleaning
How to remove and clean the Central Electronic Module or CEM for short on a Volvo. This particular car I am working with here is a 2007 Volvo C30 and a similar procedure can also be found on the S40, V50, and C70 models. Dirty connection on the CEM can cause quite a few problems either relating to the security system, ignition, gauges, wipers, power accessories, lighting, safety restraint system, a majority of electrical components in the car. For this car, my radio is experiencing an intermediate operation, especially on more humid days. This problem can also pop up if you’ve had a plugged sunroof drain or left a window open during a rain and water managed to get inside the car. #volvo #volvoc30 #volvos40
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Tools/Supplies Needed:
-3/8” drive ratchet
-3/8” drive 3” extension
-10mm 3/8” drive socket
-electrical contact cleaner
-electrical contact protectant
-clean rags
-electric brushes
Procedure:
-disconnect the battery using a 10mm socket with ratchet and 3” extension, remove the negative terminal
-the CEM is located under the dashboard
-remove the fabric cover which has two plastic clips, by just push the center in with your finger which will disconnect the clip
-to pop down there are two twist clips which need to be disconnect and then the panel can be dropped down
-there will be various electrical connectors both on the top and bottom which need to be disconnected
-for the smaller rectangular connectors, they have a lever which needs to be pulled back, this will lift the connector out of it’s location and then it’s disconnected
-for the largest connectors, there are tangs on each side which needs to be depress and they can then be pulled back
-there will also be a couple black connectors that has a tang which needs to be depress and they can be pulled straight out
-pull back the module and pull up to completely remove
-there will be similar lever style electrical connectors on the bottom that need to be disconnected too
-once fully done, the module can then be removed
-for cleaning, we’ll be using contact cleaner, something which helps dissolve corrosion
-first using a brush to remove any loose debris, try to remove as much as possible
-moving onto the contact cleaner, spray the area, allow it to soak and then agitate the surface using the bush
-wash off the area again using more contact cleaner
-repeat if needed, with some contact cleaners you may need to let the solution soak over night to remove any serious corrosion
-while the connections are free of corrosion, I’ll still go over everything just to be safe
-using the procedure, you can spray down the contacts, agitate the surface using the brush if needed, then wash away the area again with contact cleaner
-I decided to remove both electrical components to clean those areas as well
-depending on the contact cleaner, it may evaporate on it’s own either slowly or fast or you may need to dry the area off using compressed air or a clean cloth
-moving back to the car, I have laid down a shop coat to prevent any overspray from the contact cleaner
-remove any loose debris, this time you can use a toothbrush
-spray the connector using the contact cleaner and agitate using the toothbrush
-wash away any debris, then allow it to dry
-move onto the other connectors using the same process
-I left the module for a couple hours to dry and now I’ll be using an electronic terminal protectant which also helps promote connectivity
-using the supplied brush, apply the solution to the male side of the connectors
-clip the module back into it’s location, each wire has a specific shape so they cannot be mixed up
-push the module back into it’s pivot location
-I left the car sit over night just to be safe so the cleaner’s residue has a chance to dry out or evaporate
-push the module back up and screw in the retaining fasteners
-for the fabric cover, the center of the clips must be pushed out so they’re disengaged
-push the clips back into place, then push the centers in so they’re locked into place
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© 4DIYers 2013
All Rights Reserved
No part of this video or any of its contents may be reproduced, copied, modified or adapted, without the prior written consent of the author.
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Thanks for the information. Very useful. I would not have had the confidence to do this without it. I followed all of the procedure. I have a 2005 V50 car and a 2005 CEM, as it has a date on it. After removing the CEM, I could not see any evidence of either corrosion or dirt. It all looked very clean. Nonetheless, I sprayed each connector, male & female and cleaned with brushes. I will have to wait and see if it fixes my problem which is indicating the CEM is the source of various issues! Fingers crossed. If this doesn't work, I will try a reconditioned unit….. I did read elsewhere that sometimes the welds on the motherboard are a source of problems??? I think I prefer older cars which have more basic electrics!
Volvo 2005 S40i – after heater core leak – dried out restarted fine – removed CEM and cleaned thoroughly With electronic spray cleaner – remnants of antifreeze and corrosion – cleaned fuse blades coated with die electric grease. All tested OK. Replaced back in car after heater core repair. Now, I have a no start, no crank, no dashboard lights. The Key is stuck in the ignition, will move to positiion 1 and 2 with no lights. Cannot start car or remove key. The overhead lights work, brake vacuum assist and fuel pump regulator on engine come on. I must remove negative battery cable to disengage. Any thoughts would be greatly appreciated.
Out of the 2 relays, do you know which is the fuel pump relay? The large one at the bottom or the smaller one at the top?
HELP folks! Trying to diagnose the issue as local garage can’t look at it for over a month 🤦
Dashboard warning appeared saying “break system failure pull over safely” along with the traction control and ABS lights on, and Speedo not working. Breaks worked fine however but once pulled over and switched off the car won’t start as immobiliser is active.
Recovery man did some tests and found the CEM wasn’t getting any power, despite the battery and earth being fine. Fault code reads “lost communication with ABS module” is it the CEM or ABS module is the conundrum…
Thanks in advance!
Can we use canned gas or no ?
I'm going to give this a go as my C30 control panel does not come on along with the heaters
Likely saved me thousands by doing this quick fix, thank you! My 2005 Volvo t5 v50 AWD suddenly started having multiple electrical problems: wipers stuck on, no turn signals, loss of window function, loss of lock function, alarm set off while opening hood, and gas guage failure. I found corrosion at the same spot that was in the video but his looked more severe. Cleaned with no contact cleaner safe for plastic, nylon brush, blew it out like a Nintendo cartridge and presto! Everything works again! I will note that I went pretty light on the cleaner, dried for only a couple minutes and skipped the electrical contact solution. Still worked for me.
Great video
My 2010 s40 T5 AWD just developed strange behavior. I got Anti-skid warning light and transmission shifts to N, once released gas pedal it shifts back to D. Repeated this for half dozen times and just went to normal. Three days later same thing. Transmission otherwise works flawlessl.
Would you think it has potentialy ECM issues
Thank you
Would you think
You are a legend.
My s40 went nuts every warning on dash and car wouldnt start.
Checked under and brown connector not plugged in.
Plugged back in and its perfect again.
Thank you so much
Have you thought about doing pre flight safety with passengers. You have the voice for it. 😃🤣😂
My CEM looks visually good, but im experiencing some gremlings sometimes.. with CCM, CEM and IAM. I might take it a part and give it a spray
Thank you so much! I believe this is the culprit, I've had all sorts of weird electrical gremlins and following your tutorial was able to pull it out and noticed corrosion, just need to get some contact cleaner and give it a go. You are a lifesaver!!
Thank You for the video, I will be attempting to do this soon, what is the material you applied just before reassembly ? Dialectic grease?
hello. does this mean that liquid can get there? how?
there was a fire in my Volvo s40 car in this place, I want to send you photos, you can look for interest. tell me the email address and I will send the photo.
Have a go tomorrow. The car turns off various speeds. Like the ignition switching off and then on again dash lights flash come back on few seconds later .car hesitated then jumped back into life. Once engine wouldn't start after few hiccups. Noticed the cem hanging down pushed all fuses relays to see if they were loose looked good turned the 2 white tabs screwed it back up so the cem was secure car started up fine ran for few months till few hours ago cut out on my son in motorway quickly pulled over no acceleration at 70 . Told him over the phone what I did last time check it hasn't come loose. In-between cursing the car saying scrap it . Its done 247,365 miles starts first time goes like a bomb plenty of poke in engine 2006 2.0d sport wagon. Check for rust on contact or damp . Have to buy contact cleaner and small nylon brush see how it goes .
Thanks for the video!
Do you need to remove the rest of the contact cleaner from the contacts before assembly?
My Volvo C30 is going into limp mode with brake failure and abs light and anti skid. Do you think this’ll help?
Massive thank you for this video! My 04 s40 t5 threw a fit after a stall/quick restart. Wipers on, windows stuck down, interior lights, slight loss of power, no central locking, fuel gauge off. Anti skid and sas airbag warnings on dash. Followed your video step by step apart from the last fluid you applied. Car is sorted 😎👌
I bought a used S40 that is 16 years old. The car was mechanically in great shape but had one electrical problem after another. Brake failure light, immobilizer light, fuel rail code, accelerator pedal code, engine system urgent, p1070, p0240, etc etc I took out the cem, and cleaned it. It didn't look dirty, at least not the connections, but there was dust all around the Box. After cleaning up and putting it back together all codes disappeared even the check engine light is off. These should probably be cleaned every few years. Had I taking it to a dealership, they will have certainly try to sell me a new one. Those uncomfortable working on these cars should not buy one. If you don't mind getting your hands dirty little bit that's worth it
Is dielectric grease what I need for electrical contact after cleaning?
you are the man. i've watched so many of your vids and i'm so grateful you bought my car before me. haha, cheers brother
I’m having trouble with 2005 s40. The emergency flashers and high beams flicker. Not too long ago had a leak in the coolant basin and repaired. Thinking coolant may have corroded the CEM. Will try this as a fix.
Has anyone tried this for anti skid ?? Mines popped up on my 2007 volvo s40 and it will crank over or either start and turn right off I’m going to try this today and hope it works
I’m tackling this one over the weekend, for my ‘06 S40. I have an intermittent problem with driver door controls not working, as well as all of the alarms coming on at once. (It acts as if the main power connection to this CEM is being flaky, causing a restart/initialization)
Im having a CEM problem right now..have 4 codes for the accelerator pedal sensor so after i tried 2 junkyard pedals, i had to take it to the stealership..they just gave me a quote to replace the CEM for $2800..even though its a V50 AWD M66..i was debating scrapping the car..until this video gave me an option, thank you!
Really glad that I found your do-it-yourself video for module issues. I had an interlock device installed 3 years ago 4 years ago actually and I have had issues after it was installed and coincidentally my sunroof had to be fixed due to the tubes in it leaking onto the floor causing pretty significant water accumulation. So I'm not sure if those two circumstances affected the module or if one particular issue was the culprit. What occurs when I drive my car especially when it engages into turbo I will receive a notification on my dash that says anti-skid service required and then my car will go into safety mode taking it out of drive gear and if I drive it for a while it will suddenly pop abruptly into drive and if I didn't continue driving it and needed to stop and put it in park before it has a chance to pop back into gear it will go into immobilization mode locking my key thus leaving my battery on. So one mechanic told me to disconnect what appears to be some type of module in the engine that's wiping out the memory of the cars notification system I guess giving it temporary amnesia wiping out that memory that has a issue and then I'm able to restart it get my key out etc. Volvo dealership had it for a month and said they're getting a miscommunication error but they can't figure out out of the three modules where it's originating from because it doesn't misbehave when it's on the diagnostic itself. So I've been driving it like this for 2 years minimally. I've been using my deceased sisters Passat and it's alternator just went to put on me so I'm back to the Volvo drill that I have to endure randomly it only happens 5-7times a month when driven regularly. And as it is a 2004 S40 I am a single mom and a budget and I can't even fathom spending the money Volvo wants to charge me for a brand new ECM/ECU Module and a reprogramming fee wiping out my nest egg $$
for a car that has a Kelly Blue book value if $2,400.00. So with that said, I'm going to try doing exactly what you so beautifully demonstrated with the best clarity I have seen on any do it yourself tutorial that is available . Thanking you in advance for taking the time to video the process and making it so easy to understand for a person who is somewhat mechanical at least I think I'm really good mechanically but not a professional auto mechanic. Single moms have to do what they have to do and stretch a dollar pretty far. Thank you again I'll let you know if it works!!
We took the CEM out of our 2009 s40 that started great but had crazy electrical issues. It didn't look dirty but cleaned it to see if that would resolve our issues. After reconnecting the CEM the car will not start at all! Can you oro some guidance as to what we should try next?
We took the CEM out of our 2009 s40 that started great but had crazy electrical issues. It didn't look dirty but cleaned it to see if that would resolve our issues. After reconnecting the CEM the car will not start at all! Can you oro some guidance as to what we should try next?
Sir i did same way clean it and plugged it but my car isnit working what can cause the problem?
Great vid. Cheers 👍