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hoping someone can shed some light on this problem.
i have a w205 c250 cdi. Car starts with eml light on. After a min or two car remains running and dash shows all warning lights. At this point cant communicate with ecu and tcm. Once the car has been switched off it wont turn on again untill battery has been disconnected overnight. All warning lights stay on and it says without changing gear consult workshop. I can communicate with other modules which say no communication with ecm and tcm. I have checked all wires and fuses but cant seem to communicate with either of the modules.
hoping someone can shed some light on this problem.
i have a w205 c250 cdi. Car starts with eml light on. After a min or two car remains running and dash shows all warning lights. At this point cant communicate with ecu and tcm. Once the car has been switched off it wont turn on again untill battery has been disconnected overnight. All warning lights stay on and it says without changing gear consult workshop. I can communicate with other modules which say no communication with ecm and tcm. I have checked all wires and fuses but cant seem to communicate with either of the modules.
FWIW......
The 2nd battery / auxiliary battery.
This control s the transmission and ABS
Do you have an icon of a battery showing in the console message?
This has a voltage regulator which has been replaced aswell. I have also replaced the main battery. No battery icon on the dash. Battery voltage is 12.4
I have the same problem. I have replaced auxiliary, ecm and battery. The car won't cr
It still says auxiliary malfunction, don't shift contact dealer, esp fault. Does any actually any idea other than the ones said earlier? There are at least three people with this problem under this thread. Someone has to have found out something. I need solutions, and overpaying a shop for different ideas is unnecessary. Is rather just tell them what to fix, if I can.
Has anyone figured this out? I have similar issue. Car starts and runs fine after several minutes driving while coming to a stop all dash warning lights light up, blind spot inactive, braking assist not function, do not shift, parking brake warning???? Run scanner and all errors say lost communication with pcm implausible message??
Has anyone figured this out? I have similar issue. Car starts and runs fine after several minutes driving while coming to a stop all dash warning lights light up, blind spot inactive, braking assist not function, do not shift, parking brake warning???? Run scanner and all errors say lost communication with pcm implausible message??
What you describe is a network soft-crash likely caused by LOW Voltage.
Next see how chassis voltage go before/during/after X-Mas tree show
Let is see full scan fault report to see how many modules become unstable. (I know you said it's about "no COM": who's in the party?)
At fome point you can try a simple REBOOT as a temporary fix. Good for how many weeks?
How would I do a simple reboot? Is that the same as disconnecting the battery for several minutes and reconnect cause I try that and the same problem appears. I haven't been able to try much as I've been sick in bed for several days.
How would I do a simple reboot?
Is that the same as disconnecting the battery for several minutes and reconnect cause I try that and the same problem appears. I haven't been able to try much as I've been sick in bed for several days.
Yes all power removed from the vehicle: MAIN + AUX.
Get well soon, it's more important than anything else.
Hello I am also having the same issue on my w205. We managed to remove the Christmas tree lights by replacing a bunch of fuses in the engine bay, trunk, passenger footwell, and the driver side fuse box. https://fuse-box.info/mercedes-benz/...uses-and-relay. we changed many fuses and it has fixed the Christmas tree lights. we also replaced the Auxiliary
battery.
now the issue is that the car starts fine but after sitting for a while, the lights on the car (all interior and exterior lights) start flickering and the engine fan turns on, and the high beam, green lights, and fog lights on the dash come up and when that happens I cannot start the car again or use the indicators or use anything electrical with the car meaning we have to disconnect the battery to then be able to start the car again after connecting the battery 8 hours later.
we think it could be a voltage problem or alternator problem (when we rev the car sometimes all the dash lights disappear and the car is fully functional). car drives absolutely perfectly.
Hello I am also having the same issue on my w205. We managed to remove the Christmas tree lights by replacing a bunch of fuses in the engine bay, trunk, passenger footwell, and the driver side fuse box. https://fuse-box.info/mercedes-benz/...uses-and-relay. we changed many fuses and it has fixed the Christmas tree lights. we also replaced the Auxiliary
battery.
now the issue is that the car starts fine but after sitting for a while, the lights on the car (all interior and exterior lights) start flickering and the engine fan turns on, and the high beam, green lights, and fog lights on the dash come up and when that happens I cannot start the car again or use the indicators or use anything electrical with the car meaning we have to disconnect the battery to then be able to start the car again after connecting the battery 8 hours later.
we think it could be a voltage problem or alternator problem (when we rev the car sometimes all the dash lights disappear and the car is fully functional). car drives absolutely perfectly.
anything we can troubleshoot?
Your conclusion sounds right: low voltage chaos!
Check the voltages at battery terminals
do a comprehensive fault scan.
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