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Fig. 3: Diagnosis Test Oscilloscope  / Good Image Contactless High Voltage Distribution Primary Side 
(Single Image) Engine Idling  
BASIC KNOWLEDGE 
SPARK PLUGS, LOCATI  ON/TASK/DESIGN/FUNCT ION - GF15.10-P-3101F 
ENGINE 104, 111, 112, 113/, 119, 120, 137, 166 (except, 112.96, 113.98/99)    
Fig. 4: Identifying Spark Plug
 
 
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IGNITION COILS, LOCATION - GF15.10-P-3102-01A 
Fig. 5: Identifying Cylinder 1 To 6 Ignition Coil - Location On Engine 112
 Spark plugs, locationOne or two spark plugs are 
located in the cylinder head 
per cylinder. 
 Spark plugs, taskThe spark plugs ignite the 
suctioned and compressed 
fuel-air mixture due to arcing 
between the electrodes. 
 Spark plugs, designIn the manufacturer's specific 
type symbols, all the spark 
plug features are assigned (e. 
g. heat rating, shape of 
seating, thread, width across 
flats, electrode material, 
spark position). 
 Spark plugs, functionThe ignition voltage travels to 
the spark plugs from directly 
connected ignition coils or 
over the ignition lines from 
the ignition coils causing 
arcing in the air gap between 
the center and ground 
electrodes. 
 
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Fig. 6: Identifying Cylinder 1 To 8 Ignition Coil - Location Engine 113 
IGNITION COILS, FUNCTION - GF15.10-P-3102-02A 
Each spark plug is actuated separately via its own ignition coil by the ME control unit. Both ignition coils of a 
cylinder are combined to form a dual ignition coil. 
The ME control unit actuates the primary wirings (L1) of the double ignition coils at circuits 1 a or 1 b with 
ground. 
The primary current flow is interrupted at the moment of ignition timing point. As a result of the sudden 
collapse of the magnetic field the ignition voltage is generated in the secondary windings (L2). The ignition 
voltage flows through the high voltage connection (4a and 4b) and through the spark plug connector to the 
respective spark plug (R4). 
The voltage supply of the double ignition coils is protected at circuit 15 (a). 
Diodes are built-in to suppress additional ignition sparks when the primary current is switched on. 
  
Because of the diodes, it is not possible to measure the resistance in the secondary windings. 
 
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Fig. 7: Identifying Ignition Coils, Function 
IGNITION COILS, LO CATION/TASK/DESIGN/FUNCTION - GF15.10-P-3102A 
ENGINE  
112.910 /911 /912 /913 /914 /916 /917 /920 /921 /922 /923   /940 /941 /942 /943 /944 /946 /947 /949 /953 /954 /9
5
ENGINE 113.940 /941 /942 /943 /948 /960 /961 /963 /965 /966 /967 /968 /969   
Fig. 8: Identifying Ignition Coil Components 
- Shown On Engine 112
 
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ME-SFI IGNITION SYSTEM FUNCTION DIAGRAM - GF15.12-P-0001-01A 
Fig. 9: Identifying ME-SFI Ignition System Components - Engine 112 
ME-SFI IGNITION SYSTEM FUNCTION DIAGRAM - GF15.12-P-0001-01B 
 Ignition coils, location GF15.10-P-3102-01A
 Ignition coils, taskSupplying adequate 
ignition energy in all 
operating conditions for 
the particular ignition 
circuit. 
 Ignition coils, designOne double ignition coil 
for each cylinder. Attached 
to cylinder head cover. 
 Ignition coils, function GF15.10-P-3102-02A
 
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Fig. 10: Identifying ME-SFI Ignition System Components - Engine 113 
ME-SFI IGNITION SYSTEM SIGNAL ASSIGNMENT - GF15.12-P-0001-02A
 
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Fig. 11: Identifying ME-SFI Ignition System  Signal Assignment - Signal Assignment Engine 112 
ME-SFI IGNITION SYSTEM SING LE ASSIGNMENT - GF15.12-P-0001-02B 
Fig. 12: Identifying ME-SFI Ignition System Signal Assignment - Signal Assignment Engine 113  
   
TNA rpm signal on ME2.8 with 3 pulses for each engine revolution 
ME-SFI IGNITION SYSTEM   FUNCTION - GF15.12-P-0001F 
ENGINE 104.941 /943 /944 /991 /994 as of 1.8.96
 
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ENGINE 104.995  
with CODE (494a) USA version  
with CODE (807) Model year 1997  
with CODE (808) Model year 1998  
with CODE (498) as of Model Year 97 Japanese version  
ENGINE 111.921 /942 as of 1.9.98,  
111.943,  
111.944 as of 1.8.96,  
111.946 as of 1.6.98,  
111.947/973,  
111.975 as of 1.8.96  
ENGINE 111.945  
in MODEL 208.335 /435 as of 1.6.98,  
202.020/080 as of 1.9.98  
ENGINE 111.974  
with CODE (494a) USA version  
with CODE (807) Model year 1997  
with CODE (808) Model year 1998  
ENGINE 
112.910 /911 /912 /913 /914 /916 /917 /920 /921 /922 /923 /940 /941 /942 /943 /944 /946 /947 /949 /953 /954 /9
5
ENGINE 113.940 /941 /942 /943 /948 /960 /961 /963 /965 /966 /967 /968 /969  
ENGINE 119.980 /981 /982 /985  
ENGINE 120.982/983  
ENGINE 137.970  
 
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