jim1966

I have 2003 c240 and parked car when i came back out key wouldn't turn tried it for about 2 days then all of a sudden key now turns. I am at a loss. Any help is appreciated

Plutoe

Could be all sorts of things---low voltage--failing key--failing ignition module---what happens with your spare key!!

jim1966

Spare key does same both didn't turn and now both do. As soon as temp got above 35-40 it worked

RCPDesigns

Just to be clear, when you say "the key wouldn't turn" do you mean that you could not turn the key... or do you mean that when you turn the key the car wouldn't start?

When the battery gets weak these cars do strange things. You should get the battery checked. Be sure and understand how to replace the battery if you go that route. There is a certain order you must follow or you risk frying the rear SAM.

jim1966

key wouldn't turn in ignition like it was locked. i drove to work was fine temperature was 18 degrees when i parked, 4 hours later key wouldn't turn. sat for 3 days tried ignition everyday, no go tried to jump in case was battery, tried both keys. On 3rd day temperature went to 45 and ignition worked so I drove home and put in garage. I spoke to mechanic he told me that really hard to diagnose if its working. I am at a loss and don't want to throw parts at the problem.

jim1966

ok new symptom. Car ignition turned and car started. put in drive and stalled. Any suggestions and could the two be related.

RCPDesigns

OK, so we are on the same page. There are a few things to look at. I'll start with the easiest and least expensive. (though you may have already tried them).

1a) Steering lock is jammed. Try gently moving the steering wheel. It can get locked and the EIS unlock doesn't unlock it and thus you can't turn the key. Another forum member posted that their car had been parked with the wheel turned and in such a way that a curb (or something) was putting pressure on the wheel (and thus steering system).

1b) Steering lock is broken. You'll need someone to check this for you. I've only heard of this happening once and, unfortunately, it was discovered after replacing the FOB and EIS.

2) Car battery. I know you tried jumping, but I'll repeat this anyway. Crazy stuff happens in these cars when the battery isn't in top shape. The FOB is energized by the EIS. In addition the EIS will change the codes used in the key. As a result, a low battery could either keep the key from energizing or the EIS will refuse to send the codes to the key because a loss of voltage would render the system dead (this is why you don't leave you key in the ignition when you disconnect the battery).

2) Car battery. yeah, I'm repeating this. My daughter's W203 was having a bunch of strange intermittent electronic issues. Replaced the battery (which seemed fine and measured 12 volts when checked with a volt meter) and all was fine.

3) Foggy/dirty cover on EIS. Temp change (along with other weather conditions) might have fogged the cover up. Make sure it is clean and clear.

4) EIS cold/cracked solder joint. The S-Class guys have this problem. Heat the ignition slot with a hairdryer, insert the key and it turns and starts. Have the dealer replace the EIS or have a heat source handy while you wait for Spring. If I found a hairdryer fixed the problem, I'd park my car at the dealer on a cold night. Then demonstrate that a hair dryer fixes the problem and demand they replace the EIS at their cost. Nothing says defect like that. Expect to pay $1000 to have the EIS replaced.

RCPDesigns

What happened when you tried to restart? Where do you live and what is the weather like right now? I think your close to having the EIS replaced. I'd try the battery first though... much cheaper.

jim1966

Now car ignition turns (but is in garage about 45 degrees) car starts and when put in gear stalls. The battery is about 1 1/2 years old. everything works in car lights, radio etc.

RCPDesigns

The EIS and/or the key can cause the car to stall, however, it is similar to removing the key and as such could happen at any time. Stalling when putting the car in gear sounds more like a problem on its own. Have you tried placing you foot on the brake and revving the engine before going into gear? The idea is to eliminate 'load' as being a factor in the stall. If the engine is running strongly and instantly dies when put in gear, then that sounds like a switch issue (though not sure which one).

jim1966

I would agree that it sounds like a separate issue however it never has done it before the other problem started. I really know nothing much about mechanics other than doing oil changes brakes and simple stuff but I would think that two problems happening at the same time could be unrelated. However I have been wrong before at least once.

RCPDesigns

Putting the car in gear will add some load to the engine. If the engine stalls because of the load then it is a separate problem. If the engine is running strong (add light throttle pressure) and it all but shuts off just when you move the gear selector, then I would think it is the same problem and the EIS (or something) is killing the engine. The W211 had some crazy 'stop light switch' that caused all kinds of havoc when it went out... and it was a $10 switch on the brake pedal. I think at this point your best bet is to let the car warm up and see if you can drive it. You need to figure out if you've got two problems or one. If you've got one problem it is the EIS system and the battery is part of that system. Bear in mind that just because the radio, lights and everything electrical works... it doesn't mean the battery is good. Trust me on that.