2007 E550 4matic has lots errors on ESP ABS SRS speedtronic etc. Which diagnostic tool to use and how to troubleshoot? Go on reading below parts.
Car model and year:
2007 E550 4matic
Errors:
Over the last few weeks I’ve been getting a random “esp inoperative” warning. It doesn’t come on every time I drive the car and it’s usually off after restart.
Last night, I got a “right side low beam out”. Car has an aftermarket hid kit that’s been installed for about a year or so. I replaced the ballast with a spare this morning and it worked.
Took a 300 mile trip today. After about 150 miles the esp inop message popped up. Didn’t think much of it. Drove another hour and got a warning that the right side low beam was out again. Shortly after I stopped for gas and upon restarting car, I got all kinds of errors. Esp, abs, srs, speedtronic, etc.
I turned the car off and went inside the store at the gas station. When I got back in the car, it wouldn’t start. Nothing happened when turning key. No crank etc. after 5-10 mins it did start. I headed back on the road, and noticed it wasn’t shifting right. From a stop it was revving a lot to get going. All the warning lights were still on, the speedometer needle was bouncing around and the nav was (and still) stuck about 50 miles back from where I am now. Once on the highway it ran fine.
I was able to get my bt obd2 scanner and torque working at one point but it no longer does. It showed 14 codes at that time but I wasn’t able to jot them down.
At this point, the car is home. It starts every time but all the same warnings flash and as soon as it starts, the cooling fan is on full blast and won’t go off. At one point I also got a red battery icon. The battery is about 6 months old. It’s an AGM from advanced auto. I’ve since put it on a charger and fully charged it and all the same issues persist.
I thought this was an alternator or voltage regulator but since it’s charged now and having the same problem I’m not sure. Maybe an ecu issue but hoping someone has some ideas on how to proceed before towing to dealer.
Diagnostic tool to use:
Guide / Experience:
Check the voltage when the car is running. You can switch to the voltage display by switching the cluster to temperature and then hitting the odometer reset button three times with the ignition on, but without the engine running. Then once you start it, it should tell you the voltage. All those errors sound like a low voltage problem. You also have a battery control module. Search the old threads about that one. Usually voltage problems are either alternator, voltage regulator or battery control module. Your esp inoperative is a separate problem. Probably the steering angle sensor. If you search the threads you’ll find that too, there’s also a youtube video on how to replace it. You should get a real scanner that can do MB codes. I like to use a cheap Launch  x431 easydiag plus 2.0.
Make sure you get the plus version which comes with software for 2 vehicle manufacturer, there are cheaper versions, but it doesn’t come with the 2 free vehicle manufacturer software and it’s another $50 to add a vehicle manufacturer. Worked to tell me I had a bad steering angle sensor (it can also be a few other things like a wheel speed sensor, brake light switch or yaw sensor).
Finally:
Car ended up going to the dealer. They’re telling me the central gateway is/was wet and showing signs of corrosion and requires replacing. Will be a few days before that’s done. They don’t know if that is everything it will need at this point but they tell me they can’t diagnose further until that is replaced.. Looking at about $850 for this repair.
It went there for diagnostic since my friends shop was unable to read from OBD with snap-on (normally he can). Dealer was unable to connect with MB Star SDS. When they told me it was the CG, I decided to let them do this repair. If they’d told me it was an alternator and voltage regulator, I’d have had them replaced elsewhere or done it myself. When I brought it to the dealer, I was certain that replacing either of those items wasn’t going to restore all the cars systems or dash readouts or OBD. My guess was a bad alt or VR took out the ECU.