Fault codes for SBC, DPF, EGR, AdBlue/SCR and NOx

Mercedes SBC fault codes

These codes come from the reviewed SBC diagnostic reference and are grouped by the assembly concerned.

• C249FCheck the operating time of the SBC hydraulic unit (A7/3).Service and counter messages
• C2498, C235A, C235C, C2359Service threshold reached.Service and counter messages
• C2130Hydraulic unit A7/3: internal fault.Hydraulic unit and pressure accumulator (A7/3)
• C2131Pressure accumulator faulty.Hydraulic unit and pressure accumulator (A7/3)
• C2132Pressure accumulator: check precharge pressure.Hydraulic unit and pressure accumulator (A7/3)
• C2494Check the power supply to the pedal travel sensor (B37/1).Pedal travel sensor (B37/1)
• C215CCheck component S9/1 (brake light switch).Brake light switch (S9/1)
• C2100Control unit A7/3n1 (SBC control unit): internal fault.SBC control unit (A7/3n1)
• C2495Check the wake-up procedure of control unit A7/3n1.SBC control unit (A7/3n1)

Diesel particulate filter (DPF)

• P2002, P2003P2002 and P2003: understanding DPF efficiency faultsDiesel particulate filter (DPF)
• P242F, P2463, P2458P242F, P2463 and P2458: ash, soot and regenerationDiesel particulate filter (DPF)
• P244A, P244B, P2452, P2453, P2454, P2455P244A, P244B and P2452–P2455: DPF differential pressureDiesel particulate filter (DPF)

View DPF diagnostics & regeneration

Exhaust gas recirculation (EGR)

• P0401, P0402P0401 and P0402: EGR flow too low or too highExhaust gas recirculation (EGR / AGR)
• P0403, P0404, P0405, P0406, P0409, P2413P0403–P0406, P0409 and P2413: EGR control and sensorsExhaust gas recirculation (EGR / AGR)

View EGR diagnostics

AdBlue and the SCR system

• P202A, P203A, P203B, P203C, P203D, P203E, P203F, P205BP202A, P203A–P203F and P205B: AdBlue tank and levelSCR system and AdBlue
• P2047, P208A, P208B, P20E8, P20E9P2047, P208A/P208B and P20E8/P20E9: AdBlue pressureSCR system and AdBlue
• P204F, P207FP204F and P207F: AdBlue system performance and qualitySCR system and AdBlue
• P20EE, P2BADP20EE and P2BAD: SCR efficiency and NOx levelsSCR system and AdBlue

View AdBlue and SCR diagnostics

NOx sensors

• P2200, P2201, P2202, P2203, P2204, P229E, P229FP2200–P2204, P229E and P229F: NOx sensor fault codesNOx sensors

View NOx sensor diagnostics

Why we do not list every code

We only list codes whose meaning we can support with the relevant manufacturer reference or standardised generic OBD definitions. We do not create blanket explanations for unverified or manufacturer-specific meanings.

A generic code and a manufacturer-specific diagnostic description may differ in detail. Diagnosis must therefore also consider the fault status, freeze-frame data and live readings from the actual vehicle.

SBC model series covered here

• W211 (E-Class)
• W219 (CLS)
• R230 (SL)