FITMENT:
Compatible with Mercedes-Benz diesel vehicles equipped with SCR (AdBlue/DEF) Euro 6 systems, including:

• E-Class W213 / S213 / C238 / A238 (E200d / E220d / E300d OM654 engines)
• CLS C257 / X257 (CLS 220d / 300d)
• S-Class W222 / V222 (OM654 diesel variants)
• C-Class W205 (selected OM654 facelift diesel models)
• Some GL/GLC/Sprinter variants using OM654 SCR architecture

OEM / Cross reference numbers:

• A0009057108
• 0009057108
• 5WK97381 / 5WK9 7381 (SNS381A)
• A0009054704 / A0009054604 (related supersessions)

This NOx sensor is part of the Mercedes OM654 SCR aftertreatment system, used to measure nitrogen oxide levels in exhaust gases for AdBlue dosing control and emissions compliance.

FUNCTION:

• Measures NOx concentration in diesel exhaust
• Sends real-time data to ECU via CAN communication
• Controls SCR (AdBlue/DEF) injection strategy
• Monitors catalyst efficiency and emissions performance
• Ensures Euro 6 compliance and prevents engine derate

INSTALLATION POSITION:

• SCR system inlet or outlet sensor (depends on engine calibration)
• Mounted on exhaust system near DPF and SCR catalyst

IMPORTANT NOTE:
Mercedes OM654 NOx sensors like A0009057108 are highly calibration-sensitive smart sensors, meaning:

• Same physical design may have different software versions
• Upgraded versions may require both sensors replaced
• ECU adaptation/reset may be required after installation
  

Always match OEM number or VIN before ordering.

FAQ:

Q1: Is this inlet or outlet sensor?
A1: It can be used as inlet or outlet depending on W213/C238 SCR configuration and ECU mapping.

Q2: What vehicles use it most?
A2: E220d / E300d W213, CLS C257, S-Class W222 diesel OM654 engines.

Q3: What are failure symptoms?
A3: SCR/AdBlue warning light, engine derate, NOx sensor fault codes, limp mode.

Q4: Are all A0009057108 sensors identical?
A4: No — there are software/calibration variants (V2/V3 type differences in some systems).

Q5: Does installation require programming?
A5: Yes, many Mercedes OM654 systems require SCR reset or ECU adaptation after replacement.