How to repair a 2005 S40 CEM

LLW · Dec 9th, 2018, 00:18

Hi
I have a 2005 S40 2.0d. I have just bought the car and it is in "limp mode". I ran a diagnostic tool on it and it came back with DPF pressure sensor fault codes. I continued to check the DPF, EGR and the DPF pressure sensor; all was well. I then discovered a parasitic battery drain; I ran through all the fuses and relays and found fuses F18 and F4 to contain the drain. When looking onto what the fuses power, both send power to the CEM and continue to power fuses F46-47, F56-57, F79, F81-83, F86, F58-59, F74 and F77. When I checked these fuses and their circuits and their relays, all was fine again. Also when disconnecting the green plug on the CEM, my drain stopped. I researched the DPF faults on the forum and found they could be symptoms of a faulty CEM. Thus, I have come to the conclusion that because all the fuses, relays and their circuits are fine, it can only be a faulty CEM. I have taken it out of the car, but does anybody know how to repair it or look for faults on the CEM circuit board? FYI, I did also check the alternator and aircon which are not contributing to the drain. Thanks!

LizardOfBodom · Dec 10th, 2018, 11:14

Hi
CEM is usually not possible to fix if it has internal fault. Its has a lot of mainbord-type circuitry and is a pretty complicated piece of car (well, it is after all its brain) so unless its a simple, visible stuff like rust on pins or lack of connection - you may need to get it cloned. There are companies that does that for you if you get a donor part but you cant just swap it without cloning.

LLW · Dec 10th, 2018, 21:28

Hi thanks for the reply. I got another cem, I'll clone it and see if that helps. Do you know what the normal drainage should be on an S40? Thanks again.

LizardOfBodom · Dec 11th, 2018, 15:56

Quote:

Originally Posted by LLW

Hi thanks for the reply. I got another cem, I'll clone it and see if that helps. Do you know what the normal drainage should be on an S40? Thanks again.

NO clue. Alarm only takes a tiny bit, I left my car for 10 days on airport parking and it lost like 0.1 Volt over that time.

Dec 9th, 2018, 00:18	#1
LLW New Member Last Online: Dec 10th, 2018 21:29 Join Date: Dec 2018 Location: Belfast	How to repair a 2005 S40 CEM Hi I have a 2005 S40 2.0d. I have just bought the car and it is in "limp mode". I ran a diagnostic tool on it and it came back with DPF pressure sensor fault codes. I continued to check the DPF, EGR and the DPF pressure sensor; all was well. I then discovered a parasitic battery drain; I ran through all the fuses and relays and found fuses F18 and F4 to contain the drain. When looking onto what the fuses power, both send power to the CEM and continue to power fuses F46-47, F56-57, F79, F81-83, F86, F58-59, F74 and F77. When I checked these fuses and their circuits and their relays, all was fine again. Also when disconnecting the green plug on the CEM, my drain stopped. I researched the DPF faults on the forum and found they could be symptoms of a faulty CEM. Thus, I have come to the conclusion that because all the fuses, relays and their circuits are fine, it can only be a faulty CEM. I have taken it out of the car, but does anybody know how to repair it or look for faults on the CEM circuit board? FYI, I did also check the alternator and aircon which are not contributing to the drain. Thanks!

Dec 10th, 2018, 11:14	#2
LizardOfBodom WowIcanwriteAnythingHere! Last Online: Mar 26th, 2024 16:05 Join Date: May 2016 Location: Dublin/Meath	Hi CEM is usually not possible to fix if it has internal fault. Its has a lot of mainbord-type circuitry and is a pretty complicated piece of car (well, it is after all its brain) so unless its a simple, visible stuff like rust on pins or lack of connection - you may need to get it cloned. There are companies that does that for you if you get a donor part but you cant just swap it without cloning. __________________ 2005 V50 T5AWD M66, Stage1 Hilton tune E-focus torque mount, E46 bi-xenon retrofit v2 , (also available in PDF form), DTSC fully-off mod, Brembo discs+ATE ceramic pads

Dec 10th, 2018, 21:28	#3
LLW New Member Last Online: Dec 10th, 2018 21:29 Join Date: Dec 2018 Location: Belfast	Hi thanks for the reply. I got another cem, I'll clone it and see if that helps. Do you know what the normal drainage should be on an S40? Thanks again.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)