pmercury

iTrader: (2)

Customer Concern: Misfire at idle
Caution- 180 volt system- wait three minutes after turning key off before unplugging connectors on ignition system.
Average Reported Mileage: 91749

Tests/Procedures:

1. Install scan tool and check for diagnostic trouble codes. Identify what cylinders are misfiring to help with correct diagnostic route to take.

2. Isolate misfires to a bank or a cylinder quarter. With system misfire on cylinder quarter, suspect faulty coil or fuel issue. With misfires on one bank in order of firing order on that bank, testing of center power unit is needed.

3. Testing voltage output of center power unit can be done at both left and right coil connectors to compare readings. Turn key on and test with voltmeter for 175 to 190 volts between pins 8 and 16. Test for battery voltage between pins 8 and 15. Test for 21 to 25 volts between pins 8 and 14.

4. If voltages are incorrect, first verify power supply to center power unit. With key on test for voltage at pins 5 and 4. There needs to be battery voltage. Replace power supply N91 if voltage is good in but missing output voltage.

5. With scan tool data stream, verify oxygen sensors are working the same. Inspect lambda control. Compare good cylinders with misfiring cylinders, move oxygen sensors to verify faulty sensor.

6. Remove electrical connections on oil pressure sensor. If oil found, check both engine coils, engine computer, and ignition coil control unit to inspect for oil in wiring harness. Replace oil damaged components.

7. If misfires are on individual cylinders, remove ignition coils and inspect red boots for carbon tracking. If tracking is found, a new coil is needed. Remove spark plugs and inspect for oil fouling. Only install recommended spark plugs on this engine.

Tech Tips: See Mercedes service bulletin P-B-07.61/18e.
Engine has four front oxygen sensors, one for each quarter cylinder group.
If oil is found in any part of wiring harness, all components must be inspected for oil. Oil level sensor may also leak oil into harness. Due to the Ionic measurement used in misfire identification, it is recommended that factory plugs are used. If incorrect plugs are installed, it could give the control unit false information that would cause a misfire.

Diagnostic Codes
P0300
P2050


Potential Causes

Engine Control Unit
Ignition Coil
Ignition System Main Unit N91
Oil Pressure Sensor
Oxygen (O2) Sensor
Spark Plugs
Wiring Harness


Confirmed Fix Summary
Confirmed Fix

22 - Replaced Ignition System Main Unit N91
6 - Replaced Ignition Coil(s)
6 - Replaced Ignition Coil Pack(s)
3 - Replaced Spark Plug(s)
3 - Replaced Engine Oil Pressure Sensor
2 - Replaced All Oxygen (O2) Sensors
2 - Replaced Both Ignition Module/Coil Pack Assemblies
2 - Replaced Bank 1 Ignition Control Module Assembly
2 - Replaced Both Ignition Module/Coil Pack Assemblies and Replaced Spark Plug(s)
2 - Replaced Ignition Coil(s) and Replaced Spark Plug(s)
2 - Replaced Bank 2 Ignition Control Module Assembly
2 - Replaced Left Bank Ignition Coil
1 - Relearned Flywheel Ring Gear Adaptation and Replaced Mass Air Flow (MAF) Sensor
1 - Replaced Engine Oil Pressure Sensor and Replaced Engine Wiring Harness and Replaced Mass Air Flow (MAF) Sensor
1 - Replaced Both Ignition Module/Coil Pack Assemblies and Replaced Ignition System Main Unit N91
1 - Replaced Right Bank Ignition Coil
1 - Replaced Engine Oil Pressure Sensor and Replaced Engine Wiring Harness
1 - Replaced Ignition Coil Pack(s) and Cleaned Spark Plug Tubes and Replaced Spark Plug(s) and Replaced Valve Cover Gaskets
1 - Replaced Ignition Coil(s) and Replaced Ignition System Main Unit N91
1 - Replaced All Oxygen (O2) Sensors and Replaced Engine Oil Pressure Sensor and Replaced Ignition Coil(s)
1 - Replaced Mass Air Flow (MAF) Sensor
1 - Replaced Front Oxygen (O2) Sensor
1 - Replaced Vacuum Hose/Line(s)
1 - Replaced Fuel Pump
1 - Replaced Engine Oil Pressure Sensor and Replaced Engine Wiring Harness and Replaced Left Front Oxygen (O2) Sensor
1 - Repaired Ignition Coil Connector(s)
1 - Replaced Mass Air Flow (MAF) Sensor and Replaced Spark Plug(s)
1 - Replaced Coil On Plug (COP) Connector



Confirmed Fix Details
Tech Reported Fix Details Confirmed Fix



October 30, 2014 2006 Mercedes-Benz S65 AMG, 6.0L, V12, USA *
Ignition System Main Unit N91
- Replaced ignition coil assembly's high voltage regulator. mounted on top of the engine it was not supplying the needed 180 volts to bank 1
Replaced Ignition System Main Unit N91

January 18, 2010 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Ignition System Main Unit N91
- the center power unit was intermittent. installed a new m/b module& this 1 is cured
Replaced Ignition System Main Unit N91

January 18, 2017 2008 Mercedes-Benz S600, 5.5L, V12, USA *
Ignition System Main Unit N91
- no battery voltage to right side ignition coil module.
Replaced Ignition System Main Unit N91

March 20, 2014 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Ignition System Main Unit N91
- Replased Ignition Control Unit N90
Replaced Ignition System Main Unit N91

July 6, 2011 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Ignition System Main Unit N91
- Ignition system unit N91
Replaced Ignition System Main Unit N91

April 5, 2014 2007 Mercedes-Benz S65 AMG, 6.0L, V12, Des 275.982, USA *
Ignition System Main Unit N91
- IGNITION MODULE
Replaced Ignition System Main Unit N91

January 30, 2020 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Ignition System Main Unit N91 Replaced Ignition System Main Unit N91

April 6, 2019 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Ignition System Main Unit N91 Replaced Ignition System Main Unit N91

March 31, 2018 2005 Mercedes-Benz SL65 AMG, 6.0L, V12, Des 275.981, USA *
Ignition System Main Unit N91
70,000 miles Replaced Ignition System Main Unit N91

March 31, 2018 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Ignition System Main Unit N91
66,115 miles Replaced Ignition System Main Unit N91

May 21, 2015 2004 Mercedes-Benz SL600, 5.5L, V12, MFI, USA *
Ignition Coil Pack(s)
- 2004 Mercedes SL 600 Left Ignition Pack defective. Left side not running, After test fuel good, Main Ign. Control good, all voltage good at all pin tests. 52,461miles
Replaced Ignition Coil Pack(s)

December 16, 2012 2006 Mercedes-Benz S65 AMG, 6.0L, V12, USA *
Ignition Coil Pack(s)
- Replaced right side coil pack.
Replaced Ignition Coil Pack(s)

September 22, 2012 2002 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Ignition Coil Pack(s)
- right bank coil packs
Replaced Ignition Coil Pack(s)

February 17, 2017 2001 Mercedes-Benz S600, 5.8L, V12, USA *
Ignition Coil Pack(s) Replaced Ignition Coil Pack(s)

May 11, 2016 2007 Mercedes-Benz CL600, 5.5L, V12, Des 275.953, USA *
Ignition Coil Pack(s) Replaced Ignition Coil Pack(s)

September 14, 2015 2011 Mercedes-Benz CLS550, 5.5L, V8, USA *
Ignition Coil Pack(s)
80,937 miles Replaced Ignition Coil Pack(s)

July 17, 2015 2002 Mercedes-Benz SL600, 6.0L, V12, Des 120.983, USA *
Ignition Coil(s)
- Check to see if driver is working to coil pack, replace coil unit if miss-fires are all on 1 side, and receiving comand
Replaced Ignition Coil(s)

April 11, 2013 2001 Mercedes-Benz SL600, 6.0L, V12, Des 120.983, USA *
Ignition Coil(s)
- coil
Replaced Ignition Coil(s)

October 15, 2019 2007 Mercedes-Benz S600, 5.5L, V12, Des 275.953, USA *
Ignition Coil(s) Replaced Ignition Coil(s)

January 10, 2019 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Ignition Coil(s) Replaced Ignition Coil(s)

January 12, 2017 2007 Mercedes-Benz S600, 5.5L, V12, Des 275.953, USA *
Ignition Coil(s) Replaced Ignition Coil(s)

May 28, 2015 2009 Mercedes-Benz CLS550, 5.5L, V8, USA *
Ignition Coil(s) Replaced Ignition Coil(s)

March 27, 2018 2002 Mercedes-Benz S600, 5.8L, V12, MFI, USA *
Engine Oil Pressure Sensor
- Found oil in harness at all ignition components including inside M/E ECU. Cleaned out all wiring as best as possible as well as all components. Replaced leaking oil pressure sensor and seal. Clear all DTC'S and road test; all good.
Replaced Engine Oil Pressure Sensor

March 31, 2018 2002 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Engine Oil Pressure Sensor
77,000 miles Engine Oil Pressure Sensor

June 19, 2012 2002 Mercedes-Benz S600, 5.8L, V12, MFI, USA *
Engine Oil Pressure Sensor
57,993 miles Replaced Engine Oil Pressure Sensor

November 9, 2016 2005 Mercedes-Benz SL600, 5.5L, V12, MFI, USA
Spark Plug(s) Replaced Spark Plug(s)

January 15, 2019 2006 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Spark Plug(s)
- Installed the correct spark plugs.
Replaced Spark Plug(s)

July 4, 2017 2005 Mercedes-Benz SL65 AMG, 6.0L, V12, Des 275.981, USA *
Spark Plug(s) Replaced Spark Plug(s)

August 15, 2018 2002 Mercedes-Benz S600, 5.8L, V12, MFI, USA *
All Oxygen (O2) Sensors Replaced All Oxygen (O2) Sensors

February 12, 2014 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
All Oxygen (O2) Sensors
163,056 miles Replaced All Oxygen (O2) Sensors

August 6, 2016 2007 Mercedes-Benz S600, 5.5L, V12, Des 275.953, USA *
Bank 1 Ignition Control Module Assembly
- This is a replacement of a replacement. The first coil module was faulty on the first 3 cylinders (cyl 1,2,3) of the module. Showed very low Ionic Current Signal for one spark plug of each cyl. codes were 20EF, 20E7. Could not feel a misfire.
Replaced Bank 1 Ignition Control Module Assembly

August 6, 2016 2006 Mercedes-Benz S65 AMG, 6.0L, V12, USA *
Bank 1 Ignition Control Module Assembly
60,450 miles Replaced Bank 1 Ignition Control Module Assembly

August 6, 2016 2006 Mercedes-Benz S65 AMG, 6.0L, V12, Canada *
Bank 2 Ignition Control Module Assembly
- Had misfires on only three cylinders 7, 8, and 9.

50,000 miles Replaced Bank 2 Ignition Control Module Assembly

August 6, 2016 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Bank 2 Ignition Control Module Assembly
75,262 miles Replaced Bank 2 Ignition Control Module Assembly

March 30, 2018 2008 Mercedes-Benz S65 AMG, 6.0L, V12, Des 275.982, USA *
Both Ignition Module/Coil Pack Assemblies Replaced Both Ignition Module/Coil Pack Assemblies

June 30, 2015 2004 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Both Ignition Module/Coil Pack Assemblies
107,000 miles Replaced Both Ignition Module/Coil Pack Assemblies

March 31, 2018 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Both Ignition Module/Coil Pack Assemblies
Spark Plug(s)
63,867 miles Replaced Both Ignition Module/Coil Pack Assemblies and Replaced Spark Plug(s)

March 31, 2018 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Both Ignition Module/Coil Pack Assemblies
- Right bank coil had failed, customer had both replaced.

Spark Plug(s)
59,908 miles Replaced Both Ignition Module/Coil Pack Assemblies and Replaced Spark Plug(s)

November 29, 2010 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Ignition Coil(s)
Spark Plug(s)
- running rough, P0300, P0304, P0311. cyl 11 hard misfire. Check voltage at both coils, and to power unit. Remove Bank 2 coil and found cyl 11 plug tube arching to valve cover. (very noticable spot) Replace bank 2 coil unit and all 24 spark plugs.
Replaced Ignition Coil(s) and Replaced Spark Plug(s)

August 9, 2014 2001 Mercedes-Benz S600, 5.8L, V12, USA *
Ignition Coil(s)
Spark Plug(s)
- replaced plus and coil on pass side drove it hard
Replaced Ignition Coil(s) and Replaced Spark Plug(s)

March 31, 2018 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Left Bank Ignition Coil
111,000 miles Replaced Left Bank Ignition Coil

March 31, 2018 2004 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Left Bank Ignition Coil
- Engine misfired on cylinders 7 and 9.

93,466 miles Replaced Left Bank Ignition Coil

March 5, 2015 2002 Mercedes-Benz S600, 5.8L, V12, MFI, USA *
All Oxygen (O2) Sensors
Engine Oil Pressure Sensor
Ignition Coil(s)
- Oil pressure switch leaked through harness. replaced 4 upstream o2 sensors and left side coil module. vehicle runs great
Replaced All Oxygen (O2) Sensors and Replaced Engine Oil Pressure Sensor and Replaced Ignition Coil(s)

June 30, 2015 2003 Mercedes-Benz S600, 5.5L, V12, MFI, USA *
Both Ignition Module/Coil Pack Assemblies
Ignition System Main Unit N91
110,000 miles Replaced Both Ignition Module/Coil Pack Assemblies and Replaced Ignition System Main Unit N91

March 31, 2018 2002 Mercedes-Benz S600, 5.8L, V12, MFI, USA *
Coil On Plug (COP) Connector
69,000 miles Replaced Coil On Plug (COP) Connector

November 5, 2014 2001 Mercedes-Benz S600, 5.8L, V12, USA *
Engine Oil Pressure Sensor
Engine Wiring Harness
166,000 miles Replaced Engine Oil Pressure Sensor and Replaced Engine Wiring Harness

March 31, 2018 2002 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Engine Oil Pressure Sensor
- Sensor pushed oil into wiring harness.

Engine Wiring Harness
- Was contaminated with oil.

Left Front Oxygen (O2) Sensor
- Sensor was damaged by oil. This caused cylinders 10-12 to misfire.

44,000 miles Replaced Engine Oil Pressure Sensor and Replaced Engine Wiring Harness and Replaced Left Front Oxygen (O2) Sensor

June 17, 2013 2001 Mercedes-Benz S600, 5.8L, V12, USA *
Engine Oil Pressure Sensor
Engine Wiring Harness
Mass Air Flow (MAF) Sensor
84,000 miles Replaced Engine Oil Pressure Sensor and Replaced Engine Wiring Harness and Replaced Mass Air Flow (MAF) Sensor

March 31, 2018 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Flywheel Ring Gear Adaptation
Mass Air Flow (MAF) Sensor
136,931 miles Relearned Flywheel Ring Gear Adaptation and Replaced Mass Air Flow (MAF) Sensor

March 31, 2018 2002 Mercedes-Benz S600, 5.8L, V12, MFI, USA *
Front Oxygen (O2) Sensor
- Found that Front Oxygen sensor for Quadrant 4-6 was not working. Swapped sensor to different quad rent and found the fault followed the sensor. There were also several fault codes related to the operation of that Oxygen sensor including P207f and P2082.

73,000 miles Replaced Front Oxygen (O2) Sensor

December 18, 2015 2006 Mercedes-Benz SL65 AMG, 6.0L, V12, Des 275.981, USA *
Fuel Pump Replaced Fuel Pump

February 17, 2013 2007 Mercedes-Benz S600, 5.5L, V12, Des 275.953, USA *
Ignition Coil Connector(s)
- I took the black cover off the coil pack, I found that each coil has 3 electric prongs. On 1 for the prongs the wire that is soldered had cracked. I re soldered prong fixed the problem. Also saver my customer $1300 bucks on a new coil
Repaired Ignition Coil Connector(s)

March 29, 2011 2005 Mercedes-Benz SL600, 5.5L, V12, MFI, USA
Ignition Coil Pack(s)
Spark Plug Tubes
Spark Plug(s)
Valve Cover Gaskets
- p0301 p0307 p0308, oil evident from valve cover gaskets into grounded boots on coil packs. replaced valve cover gaskets and both coil packs along with all 24 MBZ spark plugs.
Replaced Ignition Coil Pack(s) and Cleaned Spark Plug Tubes and Replaced Spark Plug(s) and Replaced Valve Cover Gaskets

February 28, 2014 2004 Mercedes-Benz SL600, 5.5L, V12, MFI, USA *
Ignition Coil(s)
Ignition System Main Unit N91
- replace ignition coils power transformer
Replaced Ignition Coil(s) and Replaced Ignition System Main Unit N91

February 20, 2013 2002 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Mass Air Flow (MAF) Sensor
133,000 miles Replaced Mass Air Flow (MAF) Sensor

August 14, 2013 2001 Mercedes-Benz S600, 5.8L, V12, Canada *
Mass Air Flow (MAF) Sensor
- Had misfires on all cylinders once throttle was pressed. Engine was flooding out and all spark tests showed ok. Replaced air flow sensor and engine runs perfect.

Spark Plug(s)
- Had the incorrect spark plugs installed.

107,000 miles Replaced Mass Air Flow (MAF) Sensor and Replaced Spark Plug(s)

May 14, 2014 2001 Mercedes-Benz CL600, 5.8L, V12, SOHC, USA *
Right Bank Ignition Coil
138,765 miles Replaced Right Bank Ignition Coil

August 17, 2010 2000 Mercedes-Benz SL600, 6.0L, V12, Des 120.983, USA *
Vacuum Hose/Line(s)
- Vacuum leak at hose from RH throttle body.


Vehicle Application:
2005 CL600 5.5
2006 CL600 5.5
2007 CL600 5.5
2001 CL600 5.8
2002 CL600 5.8
2011 CLS550 5.5
2003 S600 5.5
2004 S600 5.5
2005 S600 5.5
2006 S600 5.5
2007 S600 5.5
2008 S600 5.5
2001 S600 5.8
2002 S600 5.8
2006 S65 AMG 6.0
2005 SL600 5.5
2005 SL65 AMG 6.0