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Old 07-04-2011, 09:14 AM   #1 (permalink)
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Date registered: Jul 2011
Vehicle: 2001 C240, W203
Location: Rhode Island
Posts: 2
Post Key wont turn, engine wont start

So wo days ago I went out to start my car and the key fob would not turn at all. After taking it out and jiggling it several times I got it to turn to the start position but it will not start, despite all gauges, lights, and aftermarket stereo coming on. I decided to keep playing around with it and I eventually got it to start but this time nothing electrical including all dash gauges, windows, lights did not work but the aftermarket stereo did. This cycle continues and I can only get it to start once out of every 10 times I would say. I ran a scan a pulled up 3 codes 2 with the engine not running: P0120- Throttle/Pedal position sensor, P0700- Transmission Control System and 1 while running: P0600- serial communication link.

Just had a new battery put in about 8 months ago so don't think it is related to that. I am thinking it could be a wiring problem but not sure where a harness that contains all three of these things would be located. Any suggestions?
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Old 07-05-2011, 06:05 PM   #2 (permalink)
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Date registered: Jul 2011
Vehicle: 2001 C240, W203
Location: Rhode Island
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Update

I played around with it more today searching for any signs of something wrong, so I am going to write out a detailed list of all my symptoms and problems I have discovered:

- Insert key into ignition and the sound you hear when the key is recognized isn't there, until I attempt to turn the key
- I am unable to turn the key to any position if I hesitate or let it sit in the ignition for a few seconds
- In a quick insert and turn method key turns but engine does not start
- after trying above method a few times engine will start and do one of the following;
- start normally but my check engine light is on or
- more commonly start but after a few seconds all electrical dies including, lights, windows, gas gauge, rpm gauge, blinkers and so on and as soon as everything dies the fan turns on to full speed and continues to run full blast.

I talked to a family member who has done numerous work on my car in the past and he thinks that the throttle position sensor is the culprit for all three error codes and the problems described above but he has not actually looked at the car yet. I just don't understand how that could effect so many electrical things.

I have checked all fuses and tried to find any wires that looked ruined but have found no problems.

Does anyone know of a way to test the throttle pedal sensor before I just assume thats the problem and spend the money? Or has nybody experienced anything similar with some helpful ideas? Really need to get my car back on the road and don't/ cant really afford to bring it to the dealer right now.
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Old 07-05-2011, 06:40 PM   #3 (permalink)
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Vehicle: CURRENT: 2007 CLK550 Cabriolet, 2002 C240 FORMER: 2001 ML320
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If you do not get the servo sound upon inserting the key, that means that the DAS system does not recognize the key. This is definitely not a TPS problem, it;s something electrical between the ignition switch, DAS and the ECM.
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Old 07-06-2011, 09:00 AM   #4 (permalink)
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I am having the same issues. My car usually starts in the morning, but if I have have made stops for groceries, gas etc..., while starting my key turns 90% of the time, but the engine does not start. The lights, radio work fine and the key is also recognized most of the time, so the battery seems okay.

When I am faced with the issue, I have to do the insert key, try to start the engine, if it fails remove the key and try again. Eventually it works.

Any ideas on what might be wrong?

Last edited by c240inSD; 07-06-2011 at 09:02 AM.
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Old 07-06-2011, 05:53 PM   #5 (permalink)
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Quote:
Originally Posted by c240inSD View Post
I am having the same issues. My car usually starts in the morning, but if I have have made stops for groceries, gas etc..., while starting my key turns 90% of the time, but the engine does not start. The lights, radio work fine and the key is also recognized most of the time, so the battery seems okay.

When I am faced with the issue, I have to do the insert key, try to start the engine, if it fails remove the key and try again. Eventually it works.

Any ideas on what might be wrong?
So the starter does not rotate at all? This could be the battery. Bad batteries can manifest themselves in different ways.
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