Remove/install heated O2 sensor - AR07.52-P-5303MT

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

Shown on model 246.2 

Fig 1: Heated O2 Sensor Remove/Install Components - Shown On Model 246.2

Courtesy of MERCEDES-BENZ USA

	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
	Remove/install
1	Switch off ignition
2	Lift vehicle on vehicle lift		AR00.60-P-1000AK
3	Remove engine cover
	Remove oxygen sensor upstream of catalytic converter (G3/2)
4	Unclip electrical line for oxygen sensor upstream of CAT (G3/2) on bracket (3)
5	Disconnect electrical connection for oxygen sensor upstream of CAT (G3/2x1) of oxygen sensor upstream of CAT (G3/2)
6	Remove oxygen sensor upstream of CAT (G3/2) from CAT	Coat thread with heat-resistant lubricant. Ensure that electrical line for oxygen sensor upstream of CAT (G3/2) is routed correctly.
		Oxygen sensor upstream of catalytic converter	*BA14.00-P-1005-01A
		Paste, hot lubrication 1 kg, DB supply specification 6879.20	*BR00.45-Z-1005-06A
		Engine mount wrench set	Fig 2
	Remove oxygen sensor downstream of catalytic converter (G3/1)
7	Remove engine compartment paneling		AR61.20-P-1105NKB
8	Disconnect electrical connection for oxygen sensor downstream of catalytic converter (G3/1x1)
9	Remove oxygen sensor downstream of CAT (G3/1) from CAT	Coat thread with heat-resistant lubricant. Ensure that line for oxygen sensor downstream of CAT (G3/1) is routed properly.
		Oxygen sensor at catalytic converter	*BA14.00-P-1002-01A
		Paste, hot lubrication 1 kg, DB supply specification 6879.20	*BR00.45-Z-1005-06A
		Engine mount wrench set	Fig 2
10	Install in the reverse order
11	Read out fault memory using the diagnostic system and clear if necessary
			AD00.00-P-2000-04A
	Risk of accident  from vehicle starting off by itself when engine running. Risk of injury  (bruises and burns) resulting from working on the engine while it is being started or when it is running.	Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
12	Carry out an engine test run and check exhaust system for leaktightness

Fig 2: Identifying Engine Mount Wrench Set (001 589 01 16 00)

Courtesy of MERCEDES-BENZ USA