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Hey guys, I have a strange problem. Passenger door does not lock or unlock with the remote or inside buttons. However keyless go works perfectly fine. Thus, I believe proves the lock actuator works. Would this be indicitive of a bad door module? Is the door module/actuator all in one anyway? This is on a 2009 CLS
Hey guys, I have a strange problem. Passenger door does not lock or unlock with the remote or inside buttons. However keyless go works perfectly fine. Thus, I believe proves the lock actuator works. Would this be indicitive of a bad door module? Is the door module/actuator all in one anyway? This is on a 2009 CLS
Thanks
I think you're starting to understand well how this can work and disfunction
Each door has a master controll unit (DCU) in charge of listening over CANBus-B for messaging requests.
From there is sends order to the latch unit in charge of lock actuator motor and the electric motor of window
The DCU uses pressed-pins that nearly work well. This is likely culprit to either replace or take 10mn to resolder properly.
Use a good scanner to confirm DCU faults both current and transients then figure how to extract these modules likely from the front panel built-in the door pannel for fast repairs.
Solderless CAN-B modules are responsible for battery drain while parked: DCU + Keyless + EIS are valuable repair targets.
Last edited by CaliBenzDriver; 06-12-2024 at 12:59 AM.
Awesome, thank you. I see the DCU is a separate module entirely. I will do some digging and see what I come up with.
My right side door mirror light (built into the mirror for signal/flasher) also doesn't work. I am now curious if this goes through the DCU as well?
yes, 100% guaranteed and so does the tired window motor... once fixed the mirror light will be noticeably brighter, the lock will snap up/down and the window will sound unstoppable compared to right now.
New amazing game: compare how fast each lock and window work to guess how bad your 4x DCU are.
I have the blind-spot LED built into my side mirrors and I remember light being 30% brighter... my front windows used to sound old at 10kMi. It's soldered better than new in 10mn.
... Ok, great to know. I'll leave AGM Batt connected and trickle charge it on leas acid setting. What is the downside to using AGM mode while connected?
I read your post you linked me to, most of it is completely above my head. Benz uses pressed solderless pins on the PCB?
I dont know if my old Weller would be up to the challenge, Im also interested in that Print Kote stuff. Think it would be useful in the DCU?
Unfortunately I can't diag a PCB, in your experience do most PCB just need a touch of solder or do you also come across bad components on the PCB?
Doesn't seem terrible though.
the charger outputs higher voltage (15.xV) to balance cells on AGM batteries.
The problem here is some components have very limited voltage tolerance. The audio Amp uses 16V caps!!!
So personally I dont use AGM mode with my AGM Batt. in circuit. My 8-Yr old old AUX gets very little attention.
Disconnecting all power reboots modules gone wild with bogus CAN traffic such as the CGW/SAM.
The modules I delt with did not need troubleshooting bad component level except perhaps the 3-Ph. in-tank pump controller.
It had ridiculously undersized filtering caps so I supersized that preventively.
My overall quest was to fix the nasty 11.8v Alternator output yoyo that cooks batteries with 90A charge currents.
I may well have succeeded by reworking my ESP... I have not seen voltage commended below 12.5V during accelerations and 12.6V idling. I am not claiming victory just yet, one more month!
06-11-2024, 10:36 PM
