2004 E320 4Matic no start
 

Ladies and Gents,

I believe the "neutral safety switch" on the car is faulty. All the electrics (starter/battery/etc.) work fine yet the car will not crank. When turning the ignition key, the headlights do not temporarily turn off which leads me to believe its the "neutral safety switch". However, I believe this generation of transmission does not have one. Is this simply a matter of cleaning the contact points?

At first I believed it to be the brake light switch as the car would start and shift without the brake pedal depressed. I replaced that with no result.
The car isn't throwing any codes (I have a iCarsoft MBII reader). I did replace the conductor plate and plug several months ago and its been perfect since. It worked fine, then all of a sudden, this.

Totally stumped.



Thanks for your kind assistance.

How does the starter work fine if the car won't crank?

The NSS won't cause this issue.

If this is a 722.6 trans, there is a reed switch on the conductor plate that eventually operated a relay for the starter. I don't have a wiring diagram.

The brakes don't need to be applied to start the car unless this is a verified feature I'm unaware of.

If you turn the key to the on position then jumper over the starter, does the engine run?

Have not tried that.


Is it possible its the crank position sensor? I had to replace it in my old 2000 E320 but the car would crank, just not start.

Thank you!

Is the engine turning over or you don't hear anything from it? If it is doing nothing try turning the key while pushing the gearshift over towards the right and see if it makes any difference. I had an 05 E class that every now and then, especially when hot, would start after pushing the gearshift lever over to the right slightly. Ran it like that for a couple of years before trading it on the GLK.

New Starter.

This is turning into a random throwing of parts without performing diagnosis first.


Whats a "reed switch"? I replaced the conductor plate several months ago.

A reed switch is a glass tube with small leak contacts inside. When a magnet is placed near the contacts, they open or close depending on the design. This reed switch is in the conductor plate. With a good scan tool you when read the status of this switch and watch it change state when you move the shifter. If this trans has an electric motor operating the transmission linkage, I would need to see a wiring diagram to confirm NSS location.

The brakes don't need to be applied to start the car unless this is a verified feature I'm unaware of. Didn't know that. My previous E320 (2000) did if memory serves.

Pressing the brakes to unlock the shifter is all the 00 would of had.( thank the people that drive an auto trans with one foot for causing their 80's Audi to run "away" with the fix being a shifter interlock ) Newer keyless ignition cars might have press brake before start but I'm not sure. In any event it is good practice to press the brake before starting.


If you turn the key to the on position then jumper over the starter, does the

Is it possible its the crank position sensor? I had to replace it in my old 2000 E320 but the c[/COLOR]ar would crank, just not start.

Thank you![/QUOTE]

The crankshaft position sensor tells the engine computer engine speed and position. It has no affect on cranking.

I have an 2004 E500 and from time to time, I have the same issue. Turning the key will just produce a clicking sound but the engine will not crank. I am lucky because my car has Keyless Go. So, just pressing the button on the gear shift lever starts the car.

My battery went down and I replaced it. After that the key started working and I'm able to start the car with the key also. You might try and unplug the battery for a few hours and then reconnect. This may or may not work - worth a try since it doesn't cost you anything.

If not, then you might have to replace the the ignition key module. Search and you will find people have had similar issues where they solution was to replace the module.