Hi, just bought myself a pretty worn out E240 for 1000$ with some issues

Mainly SBC malfunction and alternator

what i am wondering is can the sbc malfunction br caused by the alternator? I scanned the car with my cheap diag tool where i could see the voltage supply to the pump, all the voltages looked good but one was different from the others. The power supply relay voltage was at 4,31v. Everything else looked fine

should i replace the alternator first or try to dig even deeper into this SBC issue?

Ps. I already have ordered an alternator, just trying to figure somethings out

First, rotate the damn photos if you want help! I'm not a meerkat that can rotate its head 90 degrees!

-Get a better scan tool. You can always sell it with the car if you do not keep the car.
-Voltage is too low. Verify battery and replace if necessary.
-SBC unit shows internal fault. After replacing battery, if SBC still shows internal fault, replace SBC.
-A7/3Y6 is a solenoid internal to the SBC unit. Replacing the SBC unit replaces the solenoid inside.

Replace the SBC.

And rotate the damn photos.

Sorry my bad, first time posting here 😂
i’ve tried switching the batteries to no avail. But we will see what happens when the alternator gets here 👍 the sbc malfunction seems to appear later when i have a charger hooked up to the main battery. So crossing my fingers that thats the problem
+ i just checked the voltages again and now the power supply relay is at 11.5 v weird…

SBC is VERY sensitive to low voltage, especially the small battery up front under the hood / bonnet.

+1^
Low voltage is a killer for these cars.
If you are in the USA, there is a 25-year warranty on the SBC unit. Once voltage issues are resolved, and if the SBC still shows the fault, contact your Mercedes dealer. Mine was a free replacement of the pressure reservoir and a car wash!