jjdejd

Have a 2001 S430 with 34k miles. Battery is 10 months old. During the last week, I’ve noticed an issue when starting the car. Sometimes I’ll turn the key and nothing. Then I’ll try again and it starts? Is the switch difficult to change? Thanks

wallyp

You don't have an "ignition switch". You have an "EIS", which is a complex, expensive electronic device that serves the function of an ignition switch. You need to really, really determine what the problem actually is before you get into replacing the EIS!
You do have a start relay, which would be one good place to start testing.

Start here http://www.benzworld.org/forums/w220...ml#post5758809 and learn enough to do some simple testing, and how to get help by asking meaningful questions, so that we can try to give you meaningful answers.

tusabes

Not difficult but it's one of 4 parts coded together , so you either need to get a new one programmed by a dealer to your car (over $1000), get yours repaired since it's already programned ,

or or if you get a used one you must swap the key , ignition switch , shifter and ECU taken from the same donor car . All 4 parts must be swapped if replacing with a used one .

jjdejd

Crazy question. Could the battery in the key fob be getting low. I think the last time I changed it was almost five years ago?

wallyp

The battery or batteries in the remote key fob play no part in starting the car. The power to start the car is inductively transmitted from the EIS to the fob when the fob is inserted. The battery/batteries power the IR "summer unlocking" where the doors are unlocked, the windows and sunroof opened, and the driver's seat ventilation (if equipped) is turned on; as well as the RF door unlocking, door/trunk unlocking, and panic mode.

tusabes

Please describe what's happening in more detail - can you turn the key and will the dash lights come on and Windows work etc , but if just won't crank to start sometimes ? Or does nothing electrical come on at all?

jjdejd

I’ll have to check that info the next time it happens. It’s an intermittent problem.

S430AMG

With this type of an issue I would start at the battery, even if it's fairly new.

Put the car on and press/hold Reset on the Climate control. Once the funky menu comes up scroll to Option 22 I believe, it will show you the battery voltage, it should be above 13v while the car is running.

jjdejd

I checked the voltage while running it was 14.2v. Guess I’m back to the switch. The program is, it is so intermittent, I have a hard time figuring this out!

ItalianJoe1

Very common for the older EIS units to fail, the contacts break inside so they work intermittently.

knowbenz

EIS stands for Electronic Ignition Switch so yes he does have an Ignition Switch. EIS fail on a regular basis.

MacVidMB-V8

2nd key makes diagnosis much easier

shooffnyc

Cold weather also plays part in messing the EIS up. Someone on the forum had shown how cold weather delays the ignition from some contact points. That's one possibility.
For me, on my 01 S600, it was the starter. It was an intermittent problem. Where sometimes I would put the key in and tried but no start. Leaving the key in there for some time, up to 40 mins, then the car would all of a sudden start. Next day it would be fine. Replacing the starter fixed the issue. There was someone else who also had intermittent starting issue on their S500 and their issue was also the starter. Just some FYI. Hope the info helps. Good luck.

jjdejd

After having some time to observe this problem, it seems that the car will not start only occasionally in the morning. I’m in Florida and it’s not to cold, but I was just visiting my son in SC and it happened three times in five days first thing in the morning?? It was near freezing most mornings. I was also wondering if it could be the starter. Is there a way to test it? Thanks for everyone’s input.

knowbenz

If you have an SDS you can check actual values of circuit 50 output from EIS. Or on right fuse box there is a six pin corrector with a solid purple wire, that goes to starter solenoid. should have 12v coming out when starting the car.

jjdejd

This morning my wife told me she heard a clicking sound like the electronic starter on her stove when she had to try three times yesterday morning. I’m wondering if it’s the ignition starter relay. She said the sound came from under the dash.

knowbenz

The relay is in right front fuse box also

Dalplex

My observation is under 16 Celsius, the suspected EIS is unlikely work, which means can not turn the key.

if above 22 Celsius, the same EIS works 100%.

John Choi

mine does same thing, warm weather the key will turn but cold temp , the is not able to tune over to next position. 2003 CL55 amg, EIS is getting old and falling apart...

Dalplex

Check this video as proof that temperature is part of the reason.

John Choi

should I use a a hot pad to warm up the ignition module from the front?