Overview - Heated Oxygen Sensor And Exhaust Temperature Regulation

Vehicles with an Selective Catalytic Reduction (SCR) Catalytic Converter 

Fig 1: Heated Oxygen Sensor Exploded View

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1. Nut
   • 2 Nm
2. NOx Sensor Control Module 2 -J881- with NOx Sensor 2 -G687-
   • NOx Sensor 2 -G687- tightening specification: 50 Nm
   • Removing and installing, refer to NOx Sensor 2 -G687-, REMOVING AND INSTALLING, VEHICLES WITH A TURBOCHARGER WITH SELECTIVE CATALYTIC REDUCTION SYSTEM VERSION 2 .
3. Front Exhaust Pipe
4. Particulate Filter
5. Exhaust Gas Temperature Sensor 3 -G495-
   • 45 Nm
   • Component location, refer to appropriate service information.
   • Removing and installing, refer to appropriate service information. .
6. Heated Oxygen Sensor -G39- with Oxygen Sensor Heater -Z19-
   • 50 Nm
   • Component location, refer to Tightening specification 
   • Removing and installing, refer to Heated Oxygen Sensor -G39- WITH Oxygen Sensor Heater -Z19-, REMOVING AND INSTALLING .
   • Coat new oxygen sensors with an assembly paste
   • Only the thread may be coated with hot bolt paste on a used oxygen sensor, refer to the Parts information.
   • Assembly paste or hot bolt paste must not enter the slots on the sensor body.
7. NOx Sensor Control Module -J583- with NOx Sensor -G295-
   • Component location, refer to appropriate service information.
   • NOx Sensor -G295- tightening specification: 50 Nm
   • Removing and installing, refer to appropriate service information. .
8. Nut
   • 2 Nm
9. Exhaust Gas Temperature Sensor 2 -G448-
   • 45 Nm
   • Component location, refer to appropriate service information.
   • Removing and installing, refer to Exhaust Gas Temperature Sensor 2 - G448-, REMOVING AND INSTALLING .
10. Exhaust Pressure Sensor 1 -G450- Pressure Line
    • 45 Nm
    • Insert it into the particulate filter, clip it into the bracket and then tighten it
11. Bolt
    • 4 Nm
12. Differential Pressure Sensor -G505-
    • Removing and installing, refer to Differential Pressure Sensor -G505-, REMOVING AND INSTALLING .
13. Exhaust Gas Temperature Sensor 4 -G648-
    • Removing and installing, refer to appropriate service information. .
    • 45 Nm
14. Turbocharger
15. Exhaust Gas Temperature Sensor 1 -G235-
    • 45 Nm
    • Removing and installing, refer to appropriate service information. .
16. SCR Catalytic Converter
17. Particulate Sensor -G784-
    • Only installed on vehicles with engine code CPNB
    • Removing and installing, refer to appropriate service information. .
18. Nut
    • 2 Nm

Courtesy of AUDI OF AMERICA, LLC

For Removing and installing the Reducing Agent Injector - N474-, refer to Reducing Agent Metering System, Vehicles with a SCR (Selective Catalytic Reduction) Catalytic Converter.

Courtesy of AUDI OF AMERICA, LLC

1. Exhaust Gas Temperature Sensor 3 -G495-
2. Exhaust Gas Temperature Sensor 2 - G448-
3. NOx Sensor -G295-
4. Heated Oxygen Sensor -G39-
5. Connector for the Exhaust Gas Temperature Sensor 2 - G448-
6. Exhaust Gas Temperature Sensor 3 -G495- connector
7. Heated Oxygen Sensor -G39- connector