Fitment

GM diesel vehicles with SCR AdBlue Euro 5 Euro 6 emission system including

• Chevrolet Silverado 2500HD 6.6L Duramax diesel (2010–2014 LML platform)
• Chevrolet Silverado 3500HD 6.6L Duramax diesel
• GMC Sierra 2500HD 6.6L Duramax diesel
• GMC Sierra 3500HD 6.6L Duramax diesel
• Chevrolet Express 2500 / 3500 6.6L diesel
• GMC Savana 2500 / 3500 6.6L diesel
• Selected GM heavy-duty Duramax SCR systems (LML / early SCR generation)

OE reference
12638377
5WK96631B
19260744 (possible cross reference variant depending on calibration)

FAQ

What is this NOx sensor used for

It measures nitrogen oxide levels in diesel exhaust gas and sends data to ECU for SCR AdBlue emission control system

Is this inlet or outlet sensor

It is commonly used as SCR Position 1 (upstream NOx sensor before SCR catalyst)

Are 12638377 and 5WK96631B interchangeable

Yes, 5WK96631B is the Continental OEM reference for GM 12638377

What system does it work with

SCR Selective Catalytic Reduction system using AdBlue injection for Euro 5 and Euro 6 diesel emission compliance

What are common failure symptoms

Engine warning light SCR AdBlue fault reduced power limp mode NOx sensor communication error emission efficiency faults