thatboynii

Hi there,

Got into my car yesterday and I was unable to start it. The doors were already unlocked (sometimes my 1yr old son gets hold of the keys) - but when I put the key in the ignition I couldn't even get it to turn and do that electrical click sound it makes, so it wouldn't start. The key fob won't lock the car either, however the light is appearing on the key fob when you press the button. I had the batteries replaced in both key fobs and still nothing.

Any ideas on what might have happened?

Thanks in advance

edgarinho10

Any of the lights inside the vehicle on when you open the door? Dashboard, stereo, etc?

In other words is the battery working to begin with?

gmphertford

If battery power all ok then suspect ignition switch or steering lock, also if have spare key try that

thatboynii

Theres no lights on anywhere in the car. I can't even turn the key in the ignition to get any lights if you know what I mean?

I'm about to check the battery so will let you know.

thatboynii

Also no luck with spare key.

gmphertford

Is the battery voltage ok, check that 1st

LILBENZ230

Sounds like possible EIS failure. The keys should start the car even with no batteries in them at all.

I agree that checking the battery voltage of the car is a good idea, certainly doesn't hurt to check something simple.

Jayjosh

I have this same problem, can anybody help, what’s the solution please

Makkax1

Most probably just a low / dead battery or a blown fuse. Even a slightly low battery can cause loads of issues on W203. Can't remember what fuse numbers to check but there's at least 3. The most common one to go is the one for the starter motor. I think there's an EIS / ESL sticky on here, which probably isn't your issue but I know it lists the fuses to check for non-start / no battery power.

Lou-in-NJ

If Makkax1 "has the same problem", then the key doesn't even turn. That's an indication that the FOB's RFID capsule is not being sensed by the electronic starter lock. This could be due to a low battery, it could also be the lock since these have been known to fail. Check your car battery voltage with a digital volt meter while the car is not running, and make sure it is at least 12.4 volts. A new battery at rest will be 12.6 volts, and if your engine is running, the voltage should be between 13.6 - 14 volts.

C230 Sport Coup

Yes check everything and pray it's NOT the "Electronic Ignition Switch" or EIS for short.
Used to cost $1K to replace, likely more now. Only the dealer can do it, or someone authorized by the dealer
who can code the new EIS to the car. I've seen where it's possible
to send in your EIS along a used one and have the pertinant data chips swapped to the
replacement, and therefore possible to DIY, but DIY'in means pulling the whole dash apart to get to it.
Knock on wood. I haven't had to do it. But like everyone says check the sticky on EIS and
check fuses, and car battery etc. Battery can be dead in key and it should still work, it has inductive power, it just won't open the doors. I've noticed alot of failures of various things on these cars is due to cold solder joints Even back then mfg. were phasing out lead.
On the auto shift module for instance I've seen a number of people repair it by baking the circuit board in their oven! I wonder if it could be possible to do that with this as well? Hmmmmm

Lou-in-NJ

C230 Sport Coup, 100% agree it is solder joints. It is very rare that solid state devices just crap-out, and impossibly rare that they will work intermittently. So whenever something works sometimes and not others, it's usually a connection problem, and I agree with you that it is likely micro-fractures around soldered connections. You can use the oven method to re-flow the entire board if you know what you're doing, or use a grounded tip, surface-mount soldering iron to touch-up all the connections. Most electronics repair techs will tell you to de-solder each connection and use new solder since just re-flowing old solder means you are mixing the surface oxidation of the old solder into the re-flow, which makes for a weaker connection. With that said, my son used the kitchen oven to reflow a board in an iMAC, and it worked for a few more years after that. Also, it should be clear to readers, that as you say, the battery in the FOB is irrelevant to the ignition lock and starting of the car, when we talk about the battery, we mean the vehicle's battery, not the FOB's battery.

Makkax1

I did have exactly the same issue, including central locking not working. It was a crap battery.