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sebastian manrique
sebastian manrique, Auto Mechanic
Category: Car
Satisfied Customers: 2516
Experience:  Director Ejecutivo at Multiservicios Cruz de las Mercedes
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My 2006 S350 won’t start, They don’t seem to be corroded, I

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My 2006 S350 won’t start
JA: Have you checked the battery, particularly the terminal connections? Are they corroded?
Customer: They don’t seem to be corroded
JA: Are you fixing your S350 yourself? What have you tried so far?
Customer: I have tried jump starting it, and I can’t seem to find the diagram for my fuse boxes specific to this model. I don’t have the original owners manual either. I’m trying to fix it myself.
JA: Anything else you want the Mechanic to know before I connect you?
Customer: Yes, when I turn the key, all electronics turn on, but when I try to start it, I hear a click and a whir, but that’s it.

Hi, my name is***** your mechanic automotive expert, and I will be happy to assist you today. In some cases, I may need more information to assist better. I apologize for any delay.

Customer: replied 12 days ago.
No problem, thank you for your assistance!
So the other day right after a car wash, I parked my 2006 Mercedes S350, then came back a few hours later, tried to start it, and it wouldn’t turn on. All the electronics turned on, and when I tried to start it, I heard a click and a whir, but nothing else.
Customer: replied 12 days ago.
I’m trying to see if any fuses need to be replaced, but my car does not have the fuse diagram anywhere, and I cannot find it online for my specific model.

Dear customer, I understand. I want to explain you, the first thing I notice is that you present an important symptom of a deconfiguration in the system of recognition of the key and immobilizer, let me explain how your immobilizer system works.

The electronic immobilizer protects your vehicle by means of an electronic code integrated in the key. This is composed of an invariable personal code and a second code that the immobilizer modifies each time the engine is started.

When starting the vehicle, the immobilizer checks the personal code and the variable. If both codes are correct, the immobilizer sends a new coded signal to the engine control to unlock the engine. Without this signal, the engine can not be started, even by a bypass.

If you have a problem in the key or in the immobilizer, your vehicle will not turn on, this happens a lot when we perform works in the vehicle.
In addition if the battery has charging problems can cause this starting problems as well and cause the noise you hear.

Tthere are another factors like a problem with the battery, fuses, cylinder of the key or some sensor like the CKP sensor. Starter relay etc.

Therefore, i recommend you first try with another battery or taking out the battery and charging it to test it.
If the battery is ok, we should check the starter realy, it is located in the engine bay fuse box.
Then, if the realys and fuses are ok, we proceed to perform the diagnostic to deactivate the immobilizer becuase is the one that could caiuse the issue.

Customer: replied 12 days ago.
I have tested the battery and it seems to be okay. Where is the starter relay on this particular vehicle? I will try that next

The fuse box is located in the engine compartment (left-side on LHD, or right-side on RHD).

The starter relay is the H and J.

Here i want to share with you the diagrams you can check it yourself.

https://fuse-box.info/mercedes-benz/mercedes-benz-cl-class-s-class-c216-w221-2006-2014-fuses-and-relay

Customer: replied 12 days ago.
On this model, I have two fuse boxes, one on each side of the engine bay.

Yes, one is the pre fuse box, that one doesn't have relays and the fuse box that has in addition to the fuses the relays.

Customer: replied 12 days ago.
I believe I have found those relays, let me check to see if they’re okay

Ok great!

Customer: replied 12 days ago.
The fuses seem to be okay as far as I can tell, but the area around them is a little dirty. Could that have caused an issue? I have electronic cleaner, should I try to spray and clean it?

Yes, it is a good way to test. in addition, the fuses and relays should be checked with a tester if it is possible.

Customer: replied 12 days ago.
I do not own a tester. Would it be worth to just buy two new fuses to try out? Or just purchase the tester
Customer: replied 12 days ago.
The relay for J seemed to be more difficult to put back in

No, it is not worthy.
the relays you can interchange them, if they are same amp to test.

Customer: replied 12 days ago.
Ok let me try interchanging them. If the car still doesn’t start, what should my next step be?

The diagnostic tool with MB software as the immobilizer might be active.

Customer: replied 12 days ago.
Where can I get that tool?
Customer: replied 12 days ago.
I switched the relays but it still will not crank

Then, likely the problem is the immobilizer.
the pro tools are quite expensive so it is better to locate some garage with the tool or mechanic.

sebastian manrique and other Car Specialists are ready to help you
Customer: replied 12 days ago.
What does the tool do? Does it go around the immobilizer?