Remove/Install NOx Sensor With Control Unit Downstream Of SCR Catalytic Converter - AR49.20-P-2062OGR

Engine 642 in model 166 

with code U42 (BlueTEC diesel exhaust treatment (SCR)) 

Engine 642 in model 166 

with code U77 (Diesel Emission control BLUETEC (SCR)) 

Fig 1: NOx Sensor With Control Unit Downstream Of SCR Catalytic Converter Components Location - Engine 642 In Model 166 With Codes U42 And U77

Courtesy of MERCEDES-BENZ USA

	Risk of death  caused by vehicle slipping or toppling off of the lifting platform.	Align vehicle between vehicle lift columns and position the four support plates at the vehicle lift support points specified by the vehicle manufacturer.	AS00.00-Z-0010-01A
	Risk of burn injuries,  suffocation and poisoning when working on the exhaust system and the components connected to it. Risk of suffocation and risk of poisoning caused by inhalation of gaseous and solid components of the exhaust. Risk of poisoning  caused by skin contact with solid components of the exhaust.	Wear protective clothing and safety glasses. Use the extraction system. Move people out of the hazard area.	AS49.00-Z-0001-01A
	Risk of injury  caused by scraping or cutting body parts on sharp vehicle parts	Always wear protective gloves when working on or near sharp and non-deburred vehicle parts. Deburr repair panels.	AS00.00-Z-0017-01A
	Information on preventing damage to electronic components due to electrostatic discharge		AH54.00-P-0001-01A
	Notes on avoiding damage through contamination and foreign objects		AH00.00-P-5000-01A
	Note on calculation of tightening torque when using insertion or socket tools with various effective lengths		AH00.00-P-0015-01CW
	Notes on safety-relevant components		AH00.00-Z-0019-01A
	Remove/install
1	Remove right underfloor paneling.		AR61.30-P-1001GQ
2	Unhook line (4b) from the clamps (5).
3	Release and disconnect electrical connector from NOx sensor control unit downstream of the SCR catalytic converter (N37/8).
4	Unscrew Nuts (3).
5	Remove NOx sensor downstream of SCR catalytic converter (N37/8b1) from the exhaust pipe and remove with the NOx sensor control unit downstream of the SCR catalytic converter (N37/8).	Coat thread of NOx sensor downstream of SCR catalytic converter (N37/8b1) with heat-resistant lubricating paste
		Paste, hot lubrication 1 kg, DBL 6879.20	*BR00.45-Z-1005-06A
		NOx sensor downstream of SCR catalytic converter	*BA14.40-P-1004-02A
		Box wrench bit	Fig 2
6	Install in the reverse order.
7	Connect diagnostic system and read out fault memory and delete.	When installing a new NOx sensor downstream of the SCR catalytic converter (N37/8b1), perform reset routine.
			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
8	Perform engine test run and check exhaust system in terms of leak tightness.

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

Courtesy of MERCEDES-BENZ USA