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Hello, I've never posted here before and don't know nearly enough about cars. My C300, 2011 rwd will not start. It worked fine yesterday. It is parked in my tiny garage which is unfortunate for getting to a shop.
The lights turn on and the AC. So I think the battery must be working. There was a some noise when tried to first start it, but trying after that there is no noise of the engine trying to turn on.
All of the warning lights appear on the dash when trying to start. None of these were lit up when I drove the car yesterday.
Last maintenance was in June/July. No problems I had seen or heard. The only known issue with the car is it is missing one tire pressure sensor, so i keep an eye on that tire.
Just moved to socal from norcal, so my usual mechanic can't help and i haven't found a new one yet. Also I'm hoping I don't have to tow it out of the tiny garage it is in.
Is there any thing I should check or try to troubleshoot? Other than just calling for a tow to a new mechanic.
Thank you! The lights on the dash when try to start.
Do you own a Multimeter, if so I would check the voltage at the battery terminals, sometimes batteries can fail rather suddenly. Fully charged battery should be around 12.6V.
If the voltage check is okay, it could be the starter relay, solenoid, or the starter itself. Those can fail without warning, too. I would not initially suspect the EIS (ignition switch) or ESL (steering lock) because you do not have a warning on the instrument cluster. The brake light switch and the shift lever park position sensor have occasionally failed on these cars causing a no start, but that should also show on the center display. The warning lights being all on is a normal key on at start condition.
Trouble shooting from here depends on your level of experience and tools you have.
The next step is easy. With key out of the ignition, check fuse number 7. The fuse box is under the hood on the driver side back corner of the engine compartment.
The starter relay is labeled M.
The fuse doesn’t usually blow unless something else is wrong, but it’s easy to check.
Let us know your progress.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
I would get a Mercedes-specific scan tool and scan for codes. Otherwise, you are shooting in the dark. Every Mercedes owner should have a scan tool before anything else.
If the steering wheel unlocks and you can turn it that is a good sign.
Try starting the car in neutral.
Try jump starting it, jumper cables or battery booster. Hook the battery to a charger for awhile if thats all you have.
if you hear a click sound when turning the key to start that is a good sign, power is at least getting to the starter solenoid switch. Then either the battery doesnt have enough charge to crank the engine, or the starter is bad.
A Mercedes specific obd scanner like the Launch for $120-ish is a great investment.
If you dont have a multimeter handy to check the battery voltage you can look it up on the dash using the steering wheel buttons.
Follow the instructions for calling up the workshop menu below. Dont bother with the reading out of workshop code. You should see what is pictured in the photo on your dash. Click on Vehicle data and you should see a menu for voltage.
I would get a Mercedes-specific scan tool and scan for codes. Otherwise, you are shooting in the dark. Every Mercedes owner should have a scan tool before anything else.
Okay. Thank you everyone for the suggestions! We couldn't find the existing multimeter. We just moved so finding things is tricky. I did get a scan tool though. I finally did the scan and got a lot of errors basically saying the power is too low for a large majority of systems to function.
So this leads me to believe it is definitely the battery. So I need to either jump it or replace it. Which the manual literally doesnt tell you how to do because it doesn't want you to do. Lol.
Even if the jump works, is it likely I need to replace the battery anyways? Its about 6 years old i believe.
I'm going too look into if I can jump it properly with my fiance's prius, but that feels like it shouldn't work. Lol. Or get a jump pack I suppose. Especially as the car is still in the garage without much room.
Thank you everyone. Also the scan tool is a great purchase.
Can’t give any advice on jump starting with a Prius. If you’re tight on space, the battery booster may be the easy option. Over night on a 5 amp charger would work, too, if you have one and if the battery will charge.
If it comes to changing the battery, that’s easy in a W204. It’s under the cabin air intake plenum on the passenger side of the engine compartment against the firewall. There are 3 (maybe 4) spring clips. Lift up the plenum and the battery is right there.
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