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

MODEL 217 with ENGINE 279 

MODEL 222 with ENGINE 277, 279 

Fig 1: Heated O2 Sensor Remove/Install Components

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 and remove transmitter key
2	Remove lower engine compartment paneling		AR61.20-P-1105LF
3	Detach front exhaust system on exhaust manifold	MODEL 222 with ENGINE 277 with CODE Z07 (Top protection)	AR49.10-P-7100LF
4	Unclip electrical connection (7) or (8) of the oxygen sensor on the left downstream of catalytic converter (3) or the oxygen sensor on the left downstream of catalytic converter (4) from the retaining clamps on automatic transmission	Ensure electrical lines are routed correctly.
5	Disconnect electrical connection (7) for left oxygen sensor downstream of catalytic converter (3).
6	Disconnect electrical connection (8) for right oxygen sensor downstream of catalytic converter (4).
7	Unclip electrical connection (5) or (6) of the oxygen sensor on the left downstream of catalytic converter (1) or the oxygen sensor on the right downstream of catalytic converter (2) from the retaining clamps on the respective charge air cooler on the left or right
8	Unclip electrical line for oxygen sensor on the left upstream of catalytic converter (1) or the electrical line for oxygen sensor on the right upstream of catalytic converter (2) at holder on automatic transmission	Ensure electrical lines are routed correctly.
9	Disconnect electrical connection (5) for left oxygen sensor upstream of catalytic converter (1).
10	Disconnect electrical connection (6) for right oxygen sensor upstream of catalytic converter (2)
11	Remove left oxygen sensor upstream of CAT (1) or right oxygen sensor upstream of CAT (2) or left oxygen sensor downstream of CAT (3) or right oxygen sensor downstream of CAT (4)	Coat thread with hot lubrication paste. Oxygen sensor at catalytic converter	*BA14.00-P-1002-01A
		Oxygen sensor upstream of catalytic converter	*BA14.00-P-1005-01A
		Paste, hot lubrication 1 kg, DBL 6879.20	*BR00.45-Z-1005-06A
		Box wrench bit	Figure
12	Install in the reverse order
13	Read out fault memory using the diagnostic system and clear if necessary
			AD00.00-P-2000-04B
	Check
	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
14	Carry out an engine test run and check exhaust system for leaktightness

Fig 2: Identifying Box Wrench Bit (000 589 71 03 00)

Courtesy of MERCEDES-BENZ USA