Keithb

My 09 C63 has been doing something I think is a little odd recently.

I unlock it, insert the key and turn, nothing. Dash / instrument panel lights up, but nothing when I turn the key. No clicking, no errors, nothing. Most of the time if I turn it off, remove the key, lock and unlock, it will fire up no problems.
Once or twice it's given me the warning that ESP is not active and the runflat is not active. But same thing, remove key, lock, unlock, turn key, engine fires just fine. I drive off, no errors or warnings and the car runs just fine.

This has happened both when the car has been run earlier the same day and when it's been parked for a few days.

I'm wondering if this is a battery / charging issue or perhaps a sensor somewhere?

Anyone else have thins issue?

jptaylor

my initial guess would be battery.....when mine went about 1.5yr ago it did the EXACT same thing

w203ck

Maybe a connection issue with the battery terminals or control module. No way a battery would drain to that extent within such a short amount of time.

jptaylor

Sure it can...these cars are UBER sensitive to voltage and it only takes a weak cell to give them fits....like I said, mine did the exact same thing as described....it would crank fine, fine, fine and then it just wouldn't start...charge it then it would crank fine,fine,fine and no start....put a new AGM battery in and have had zero issues since....I got my AGM from Advance and my cost was around $130, I believe their retail was around $175 which still isn't that bad

QWKSNKE

If it isn't the battery, it's the ignition switch. Mine in my 2008 went out all of sudden last summer. I too thought it was the battery but the 8 year old battery checked good.
Does your steering wheel unlock when you turn the key? Can you move the trans selector out of Park? If no, it's the ignition switch. Bad news is, it's not a DIY fix. It has to go to a dealer or independent shop who specializes in mercedes cars and has the authority to order theft system parts.
Cost me $750 for part and labor. (Plus tow) Dealer estimate was around $1500

C63fora2w1

First thing I thought of was a bad ground.. check your negative battery cable

ChatWithaNinja

this happens to me once in a while as well.
Thanks for the test ideas. I'll try that next time this happens. I do know that the battery isn't correct for the car according to my mechanic (post purchase inspection) so I'm hoping the battery is my problem.
If not the battery and it is the ignition I'll do a pre-emptive strike on that... things like that fail only in the worst possible moments...

FCPEuro

Be sure to verify your steering column is unlocking, this could be early signs of an ESL issue.

--Kyle

QWKSNKE

this is exactly what i was referring to in my above post

Keithb

Since it doesn't happen often, I'll try to remember to try that next time. Thanks

ChatWithaNinja

So I'm bringing this one back to hand out some results. I finally had the ignition issue happen again and I was able to shift and turn the wheel so I am looking at a battery issue.
Like I mentioned before, my post purchase inspection showed that the battery wasn't spec, so I'm confident (and happy) that is the issue and not the ignition switch.

thanks for the help!

BLKROKT

Did you try changing the intake manifold gaskets? Bet that fixes it!

- Dave

Jasonoff

Gotta remove the engine for that. It only takes an hour though...

bluejae

check battery terminal connections. make sure they are very tight.
check ground cable
test battery for bad cells and maybe even check the alternator

Keithb

So, a quick update on this.

I had it happen again on the weekend. This time however, nothing I did would get the car to start.
Lock/unlock - nothing
Boost with a donor - nothing
Leave it it for a few minutes and try again - nothing.

Same symptom - instrument panel lights up, trac control and run flat inactive warnings come up, no start, no starter clicking - nothing at all.

Steering wheel unlocked and I was able to move the shift lever up and down, even tried to start in N - nothing.

Called CAA - got towed to local garage. Once there, after car came off the tow truck, thought I'd try one more time and FFS it fired first turn.

Shop has had it for a couple of days, have tested battery, alternator etc, etc, say they can't find anything, no codes no nothing. All connections are tight nothing loose.

Rather frustrating.

Thoughts?