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W221 & Audio Moderator
2013 S550
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10,874 Posts
Discussion Starter #1 (Edited)
NOTE: What follows is meant to be a suggestion as to what may be causing the problems. However, there may be other causes of the problem that can be found ONLY by proper STAR (DAS) diagnosis. While the components below may be the cause more often than not, proceeding without proper diagnosis can result in just throwing parts at the problem, and failure to cure it.

Poor Acceleration - Suspect a bad accelerator module - see Acceleration Problem - MBWorld.org Forums - How to change accelerator pedal module, post 5 at http://www.benzworld.org/forums/w220-s-class/1349537-error-code-p0120-w220.html

Excessively long cranking time when starting cold, rough running on an intermittent basis, poor idle, stumbling or hesitation, a drop in mileage and stalling upon acceleration – suspect a Camshaft Position Sensor failure. A photo of the CAMSHAFT position sensor is at - post 2, http://www.benzworld.org/forums/w220-s-class/1563398-yet-another-cam-position-sensor-question.html

Car stalls after engine has warmed up – suspect a bad Crankshaft Position Sensor - http://www.benzworld.org/forums/w220-s-class/1307031-2000-s500-problem-please-help.html. A photo of a crankshaft position sensor is at post 11, http://www.benzworld.org/forums/w220-s-class/1563398-yet-another-cam-position-sensor-question-2.html

NOTE that the Crankshaft Position Sensor and the Camshaft Position Sensor are different modules, but they must work in synch to keep the engine running. Read more: Camshaft Position Sensor Failure Symptoms | eHow and Differences Between a Camshaft Sensor & a Crankshaft Sensor | eHow

Loss of power, misfiring - Suspect a bad Mass Air Flow (MAF) Sensor - especially with code P20D4. Also, don't overlook a bad accelerator module as cause of loss of power, especially if there is no roughness or misfire.

Common Symptoms of a bad Manifold Absolute Pressure (MAP) sensor are:
1) A rich or lean fuel mixture*resulting in a gas smell after the engine has warmed up, or engine knocking or pinging at times for no apparent reason
2) Excessive fuel consumption
3) Rough idle
4) Hesitation or slight jerking during acceleration, or when putting the vehicle into drive
5) stalling or dying immediately after you try to give the engine gas to start the car moving

Check Engine Light – Diagnosis of a Check Engine Light should be done with STAR Diagnostics; codes should be read to avoid misidentifying the problem and throwing money and parts at it.

Car will not turn over or key refuses to turn in ignition, especially in cold temperatures: This is an indication of an Electronic Ignition System failure. The EIS is coded to your car as an anti-theft measure, and it is expensive to replace. However, Many expensive Mercedes electronic components can be repaired rather than replaced, including the EIS. some of the other items include Engine Control Unit (ECU), Navigation Command Unit, Instrument Cluster, Throttle Body, Central Lock Vacuum Pump, CD Changer, Amplifier, A/C Control Unit, Gear Shifter, Seat "Brain," and Airmatic system components. See Mercedes Comand Repair M and B Specialist - Mercedes Electronic Repair
 

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Premium Member
2000 CLK 430 Cabriolet 2003 S500 4Matic 2004 S55 2005 CLK 500 Cabriolet 2008 S 450
Joined
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780 Posts
Good work Skylaw. I've had the S500, S55, CLK 430 an d CLK 500. I'm really leaning towards a W 221. This piece of work will come in handy, for sure. Again - GOOD WORK!
 

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Outstanding Contributor Always Remembered RI
Zotye Auto 1.5T T600 2016
Joined
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52,804 Posts
Great post as usual my friend but I must add a word of caution here, to say suspect this or that is not a good way to start any form of diagnosis, fault codes are number one.

For instance a problem starting a hot engine is almost always the CPS BUT many other parts can cause this so fault codes are the way to go first. Thus avoiding the "throw parts at a problem syndrome".
 

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W221 & Audio Moderator
2013 S550
Joined
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10,874 Posts
Discussion Starter #4
You are correct, Eric - replacing parts without diagnosis is always taking a risk, and in many cases, a foolhardy risk. For things like the Camshaft and Crankshaft Position Sensors, the cost of parts isn't particularly high (but the effort to replace them can be significant for shade tree mechanics). Still, your point is well-taken, and I have added a caveat at the top of the first post.

For parts like the EIS, which is very expensive new, diagnosis ahead of replacement is the only way to go; the main thing here is the part can be repaired rather than replaced.

The only way to be certain is with proper diagnosis.
 

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Registered
Joined
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4 Posts
I’ve searched the form skylaw and your information has kept my 3 Mercedes on the road thank u so much. My problem is different. My 04 s55 amg seems to hit a brick wall around 125 mph. I made a post I would realy appreciate if you could email me I’m stumped. [email protected]
 

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Registered
2001 210.082 +494, 2008 221.176 +494
Joined
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154 Posts
NOTE: What follows is meant to be a suggestion as to what may be causing the problems. However, there may be other causes of the problem that can be found ONLY by proper STAR (DAS) diagnosis. While the components below may be the cause more often than not, proceeding without proper diagnosis can result in just throwing parts at the problem, and failure to cure it.

Poor Acceleration - Suspect a bad accelerator module - see Acceleration Problem - MBWorld.org Forums - How to change accelerator pedal module, post 5 at http://www.benzworld.org/forums/w220-s-class/1349537-error-code-p0120-w220.html

Excessively long cranking time when starting cold, rough running on an intermittent basis, poor idle, stumbling or hesitation, a drop in mileage and stalling upon acceleration – suspect a Camshaft Position Sensor failure. A photo of the CAMSHAFT position sensor is at - post 2, http://www.benzworld.org/forums/w220-s-class/1563398-yet-another-cam-position-sensor-question.html

Car stalls after engine has warmed up – suspect a bad Crankshaft Position Sensor - http://www.benzworld.org/forums/w220-s-class/1307031-2000-s500-problem-please-help.html. A photo of a crankshaft position sensor is at post 11, http://www.benzworld.org/forums/w220-s-class/1563398-yet-another-cam-position-sensor-question-2.html

NOTE that the Crankshaft Position Sensor and the Camshaft Position Sensor are different modules, but they must work in synch to keep the engine running. Read more: Camshaft Position Sensor Failure Symptoms | eHow and Differences Between a Camshaft Sensor & a Crankshaft Sensor | eHow

Loss of power, misfiring - Suspect a bad Mass Air Flow (MAF) Sensor - especially with code P20D4. Also, don't overlook a bad accelerator module as cause of loss of power, especially if there is no roughness or misfire.

Common Symptoms of a bad Manifold Absolute Pressure (MAP) sensor are:
1) A rich or lean fuel mixture*resulting in a gas smell after the engine has warmed up, or engine knocking or pinging at times for no apparent reason
2) Excessive fuel consumption
3) Rough idle
4) Hesitation or slight jerking during acceleration, or when putting the vehicle into drive
5) stalling or dying immediately after you try to give the engine gas to start the car moving

Check Engine Light – Diagnosis of a Check Engine Light should be done with STAR Diagnostics; codes should be read to avoid misidentifying the problem and throwing money and parts at it.

Car will not turn over or key refuses to turn in ignition, especially in cold temperatures: This is an indication of an Electronic Ignition System failure. The EIS is coded to your car as an anti-theft measure, and it is expensive to replace. However, Many expensive Mercedes electronic components can be repaired rather than replaced, including the EIS. some of the other items include Engine Control Unit (ECU), Navigation Command Unit, Instrument Cluster, Throttle Body, Central Lock Vacuum Pump, CD Changer, Amplifier, A/C Control Unit, Gear Shifter, Seat "Brain," and Airmatic system components. See Mercedes Comand Repair M and B Specialist - Mercedes Electronic Repair
FWIW, I can make used SmartKey EIS components (and many others) appear “new” if anyone can source a used one and sends it to me. It can be programmed “as new” but dealer tools would be required and the dealer is unlikely to perform such as service. If anyone has an older MB that makes it cost prohibitive of puchasing a new EIS, ELV, ESM, IC, etc, they are welcome to contact me via PM to describe their needs.
 
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