Mercedes-Benz Diagnostic Trouble Codes

Common OBD2 fault codes found on Mercedes-Benz vehicles with model-specific causes, known issues, TSBs, and adjusted repair cost estimates. Each guide is tailored for Mercedes-Benz owners.

Fuel System

P0170Moderate

Fuel Trim Malfunction (Bank 1)

Mercedes C-Class • 2007-2024

The M271 and M274 engines can develop intake manifold swirl flap issues that cause vacuum leaks and ...

P0191Moderate

Fuel Rail Pressure Sensor Circuit Range/Performance

Mercedes C-Class • 2008-2024

The M274 2.0T and OM651 diesel engines use Bosch fuel rail pressure sensors. On the diesel, P0191 ca...

Misfire

P0304High

Cylinder 4 Misfire Detected

Mercedes C-Class • 2007-2024

The M274 2.0-litre turbo engine in the C200/C250 (W205) has documented issues with ignition coil fai...

Electrical

P0606Critical

ECM/PCM Processor Fault

Mercedes C-Class • 2007-2024

W204 and W205 C-Class models with the ME9.7 and MED40 ECUs can develop P0606 from moisture intrusion...

Transmission

P0700High

Transmission Control System Malfunction

Mercedes C-Class • 2007-2024

The W204 C-Class with the 722.9 (7G-Tronic) transmission commonly triggers P0700 due to conductor pl...

P0720High

Output Speed Sensor Circuit Malfunction

Mercedes C-Class • 2007-2024

The W204 and W205 C-Class with the 722.9 (7G-Tronic) transmission uses a speed sensor integrated int...

P0741Moderate

Torque Converter Clutch Circuit Performance/Stuck Off

Mercedes C-Class • 2007-2024

The W204 C-Class with the 722.9 (7G-Tronic) transmission is known for TCC shudder and lockup issues....

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