NOx sensor 4M0907807G — Audi Q7 / SQ7

The NOx sensor is a central component of exhaust aftertreatment. It consists of
a probe and a control unit, is integrated into the exhaust system as a complete unit,
and detects nitrogen oxides (NOx) in the exhaust flow. Its use ensures compliance
with strict emission standards such as Euro 5 and Euro 6.

Areas of Application

• Modern diesel vehicles with exhaust aftertreatment (e.g., SCR, LNT)
• On-board monitoring and regulation of emissions

Operating Principle

• Operation at high exhaust temperatures
• Dual-chamber principle: NOx is catalytically split, and the resulting oxygen is measured
• Signal transmission via CAN bus to the Engine Control Unit (ECU)

Technical Highlights

• High-precision NOx detection under real driving conditions
• Fast response time during dynamic load changes
• Robust design for continuous operation at high temperatures
• Integrated control unit for signal conditioning and diagnostics

Benefits

• Reliable compliance with Euro 5/Euro 6 limits
• Optimized exhaust aftertreatment (e.g., AdBlue dosing)
• Reduced emissions and improved efficiency
• High measurement accuracy ⇒ reduced need for recalibration
• Quality replacement available in OE specification

Interfaces & Communication

• CAN bus for data transmission to the ECU
• OBD-capable status and error messages

Installation Instructions

• Mount directly in the exhaust tract according to manufacturer specifications
• Position thermally correct (observe heat protection)
• Electrical connection to ECU/CAN network; check tightness and cable routing

Scope of Delivery

• NOx probe with integrated control unit
• Mounting hardware (model-dependent)
• Installation and safety instructions

Note: Due to the high technical complexity and the required measurement accuracy,
the use of replacement parts in OE quality is recommended.