Remove/install ignition coils - AR15.12-P-2003MT

ENGINE 133 in MODEL 117, 156, 176 

ENGINE 270 in MODEL 117, 156, 176, 242, 246.2 

Shown on ENGINE 270.910 in MODEL 117 

Fig 1: Ignition Coils Remove/Install Components - Shown On Engine 270.910

Courtesy of MERCEDES-BENZ USA

Shown on ENGINE 133 in MODEL 176 

Fig 2: Ignition Coils Remove/Install Components - Shown On Engine 133

Courtesy of MERCEDES-BENZ USA

	Risk of death  caused by contact with parts conducting high voltages.	Do not touch parts which conduct high voltages. Persons who have electronic implants (e.g. cardiac pacemakers) may not perform any work on the ignition system.	AS15.10-Z-0001-01A
	Risk of injury  . Skin or eye injuries may result when handling hot or glowing objects.	Wear protective gloves, protective clothing and safety glasses, if necessary.	AS00.00-Z-0002-01A
	Notes on avoiding damage to ignition system		AH15.10-P-0002-01V
	Remove/install
1	Switch off ignition
2	Remove upper engine cover (1)
3.1	Remove air intake pipe (2)	ENGINE 270 in MODEL 117, 156, 176, 242, 246.2 without CODE 494 (US version)
			AR09.10-P-8131MT
3.2	Detach air intake pipe (2) at turbocharger and air filter housing and lay outside the working area	ENGINE 270 in MODEL 117, 156 with CODE 494 (US version)
			AR09.10-P-8131MTU
		The vent lines, the oil separator and the air intake pipe (2) are firmly connected together. Therefore the oil separator, the vent lines and the air intake pipe(2) must be replaced after disconnection of the connection.
3.3	Detach holder (8) on turbocharger and place vent lines and purge lines to one side	ENGINE 133 in MODEL 117, 156, 176 Do not bend vent and purge lines too strongly. Leaks and damage can occur otherwise and this must be replaced.
		Bolt, bracket for vent line	*BA09.40-P-1008-01X
4	Detach coolant hose from holder (9) and place to one side	ENGINE 133 in MODEL 117, 156, 176
5	Disconnect electrical connection for oxygen sensor upstream catalytic converter (G3/2x1) from bracket (9)	ENGINE 133 in MODEL 117, 156, 176
6	Remove bracket (9)	ENGINE 133 in MODEL 117, 156, 176
7	Disconnect electrical connection on ignition coils (T1/1 to T1/4)
8	Remove screw/bolts (3) for ignition coils (T1/1 to T1/4)	Screw/bolt, ignition coil to cylinder head cover	*BA15.10-P-1001-04A
9	Detach ignition coils (T1/1 up to T1/4) with spark plug connectors (a) upwards and remove
	Check
10	Check ignition coils (T1/1 up to T1/4) and spark plug connectors (a) for damage and replace if necessary
11	Check protective hose and spark plug connector at ignition coil (T1/1 up to T1/4) and replace if necessary	For renewal of the spark plug connector (a), the cutouts are fully engaged in the boat shells on both sides.
12	Install in the reverse order
13	Read out fault memory using the diagnostic system and clear if necessary
			AD00.00-P-2000-04A