Mercedes-Benz Engine Control Fault Codes List
MR fault codes in Mercedes-Benz vehicles detect if there are malfunctions with the engine – speed is too high, charge pressure deviation is too large, charge pressure for braking operation is not reached or the oil pressure is too low.
Fault codes
| Code | Description |
|---|---|
| MR0101 | Can-L-Link To The Faulty Fr |
| MR0102 | Data From The Control Unit Fr (Motion Control) Wrong |
| MR0104 | Can-Connection To Faulty Fr |
| MR0149 | Can Parameterization Error |
| MR0204 | Can-High-Wire To The Scr-Module Frame (Euro 4 Or Euro 5) Is Faulty. |
| MR0308 | Crankshaft Position Sensor, A Short To Ground |
| MR0309 | Crankshaft Position Sensor, A Circuit Break |
| MR0310 | Crankshaft Position Sensor: The Signal Is Too Weak |
| MR0311 | Crankshaft Position Sensor: Incorrect Synchronization Of Crankshaft And Camshaft Signals. |
| MR0312 | Crankshaft Position Sensor: No Signal |
| MR0313 | Crankshaft Position Sensor: Wrong Polarity. |
| MR0408 | Sensor Camshaft Position, A Short To Ground |
| MR0409 | Sensor Camshaft Position, A Circuit Break |
| MR0412 | Camshaft Position Sensor: No Signal |
| MR0413 | Camshaft Position Sensor: Wrong Polarity |
| MR0530 | Exceeding Speed |
| MR0612 | Signal 'Fan Speed' Is Missing. |
| MR0631 | Fan Speed Too Low. |
| MR0722 | After The Temperature Of The Catalyst Is Too High. |
| MR0782 | The Catalyst Is Absent. |
| MR0788 | Before The Catalyst Temperature Is Too High (The Threshold Value Is Exceeded 1). |
| MR0789 | Before The Catalyst Temperature Is Too High (The Threshold Value Is Exceeded 2). |
| MR0797 | Before The Catalyst Temperature Is Too High (Reduced Engine Power). |
| MR0815 | Temperature Sensor Before The Catalytic Converter Is A Circuit Break Or Short Circuit To Positive. |
| MR0816 | Temperature Sensor Before Catalytic Converter Has A Short To Ground. |
| MR0915 | Temperature Sensor After The Catalytic Converter Has A Circuit Break Or Short Circuit To Positive. |
| MR0916 | Temperature Sensor After The Catalytic Converter Has A Short To Ground. |
| MR1015 | Oil Temperature Sensor Has Exceeded The Measuring Range (Short To Positive, A Circuit Break). |
| MR1016 | Oil Temperature Sensor Has Not Reached The Minimum Value Of The Measuring Range (Short To Ground). |
| MR1115 | Fuel Temperature Sensor Has Exceeded The Measuring Range (Short To Positive, A Circuit Break). |
| MR1116 | Fuel Temperature Sensor Has Not Reached The Minimum Value Of The Measuring Range (Short To Ground). |
| MR1215 | Combined Sensor 'Boost Pressure And The Temperature Of The Charge Air': Temperature Sensor, The Measurement Range Is Exceeded (Short To Positive, A Circuit Break) |
| MR1216 | Combined Sensor 'Boost Pressure And The Temperature Of The Charge Air': The Temperature Sensor Is Not Reached At Least The Measuring Range (Short To Ground) |
| MR1315 | The Atmospheric Pressure Sensor, Measuring Range Is Exceeded (Short To Positive, A Circuit Break). |
| MR1316 | The Atmospheric Pressure Sensor Is Not Reached The Minimum Value Of The Measuring Range (Short To Ground). |
| MR1415 | Combined Sensor 'Boost Pressure And The Temperature Of The Charge Air': A Pressure Sensor, The Measurement Range Is Exceeded (Short To Positive, A Circuit Break) |
| MR1416 | Combined Sensor 'Boost Pressure And The Temperature Of The Charge Air': Pressure Sensor Does Not Reach The Minimum Measuring Range (Short To Ground) |
| MR1417 | Combined Sensor 'Boost Pressure And The Temperature Of The Charge Air': A Pressure Sensor, The Measured Value Is Invalid |
| MR1515 | Sensor, The Measurement Range Is Exceeded The Coolant Temperature (Short To Positive, A Circuit Break). |
| MR1516 | The Coolant Temperature Sensor Is Not Reached The Minimum Value Of The Measuring Range (Short To Ground). |
| MR1615 | Oil Pressure Sensor, Measuring Range Is Exceeded (Short To Positive, A Circuit Break). |
| MR1616 | Oil Pressure Switch Not Reached The Minimum Value Of The Measuring Range (Short To Ground). |
| MR1617 | Oil Pressure Sensor, The Measured Value Is Invalid |
| MR1715 | Combined Active Exceeded The Measuring Range |
| MR1716 | Combined Active Reach The Minimum Measuring Range |
| MR1717 | Combined Active Implausible Signal |
| MR1818 | Discharge Circuit Is Faulty |
| MR1820 | Boost Pressure Is Exceeded |
| MR1822 | The Temperature Of The Charge Air Is Exceeded |
| MR1873 | The Speed Of The Turbocharger Is A Violation Of Uniform Motion. |
| MR1874 | Deviation Setpoint Charge Air Pressure Regulation Is Too High. |
| MR1876 | Charge Pressure For Braking Mode Is Not Enough. |
| MR1878 | Discharge Circuit Is Faulty |
| MR1917 | The Measured Fuel Pressure Sensor Value Is Invalid. |
| MR2017 | The Measured Oil Pressure Sensor Value Is Invalid. |
| MR2020 | The Oil Pressure Is Too Low. |
| MR2021 | The Oil Pressure Is Too Low. |
| MR2026 | Engine Oil Level Is Too High Or Too Low. |
| MR2122 | The Coolant Temperature Is Too High. |
| MR2219 | Mr Terminal 15 Of The Control Unit Or Fr Has A Circuit Break. |
| MR2319 | Mr Terminal 50 Of The Control Unit Or Fr Has A Circuit Break. |
| MR2415 | The Differential Fuel Pressure Sensor Has A Circuit Break. |
| MR2416 | The Differential Fuel Pressure Sensor Has Short To Positive, Mass. |
| MR2509 | The Oil Level Sensor: A Circuit Break |
| MR2515 | Oil Level Sensor Short Circuit To Positive, The Measurement Range Is Exceeded |
| MR2516 | Oil Level Sensor, A Short To Ground, Do Not Reach The Minimum Measuring Range |
| MR2517 | The Oil Level Sensor: The Measured Value Is Invalid |
| MR2612 | Turbocharger Speed Sensor Is A Circuit Break, Short To Ground, Short To Positive. |
| MR2615 | Turbocharger Speed Sensor Is Short To Positive, A Circuit Break. |
| MR2616 | Turbocharger Speed Sensor Is Short To Ground. |
| MR2712 | Signal Speed Of The Generator Is Missing (Time Out) .Or Turbocharger Speed Sensor Is A Circuit Break, Short To Ground, Short To Positive (Turbocharger 2). |
| MR2804 | Nox Sensor Is A Violation Of Bonds. |
| MR2815 | Nox Sensor Has A Short Circuit To Plus, A Circuit Break. |
| MR2816 | Nox Sensor Has A Short Circuit To Ground. |
| MR2971 | Too High Emission Of Nitrogen Oxides (1 Threshold Is Exceeded) |
| MR2972 | Too High Emission Of Nitrogen Oxides (2 Threshold Value Is Exceeded) |
| MR3015 | The Fuel Pressure Sensor, Measuring Range Is Exceeded (Short To Positive, A Circuit Break) |
| MR3016 | The Fuel Pressure Sensor, Will Not Reach The Minimum Measuring Range (Short To Ground) |
| MR3115 | Temperature Sensor 2 Has Charge Air Gap Circuits. |
| MR3116 | Temperature Sensor 2 Charge Air Has A Short Circuit. |
| MR3215 | Egr Sensor Temperature Has A Discontinuity Circuits. |
| MR3216 | Temperature Sensor For Exhaust Gas Recirculation System Has A Short Circuit. |
| MR3332 | Recirculated Exhaust Gas Temperature Sensor: Value Out Of Range. |
| MR3415 | Humidity Sensor Has A Short Circuit To Positive, A Circuit Break. |
| MR3416 | Humidity Sensor Has A Short Circuit To Ground. |
| MR3515 | Air Temperature Sensor Has A Short Circuit To Positive, A Circuit Break. |
| MR3516 | Air Temperature Sensor Has A Short Circuit To Ground. |
| MR3604 | No Can Message 'Temperature'. |
| MR3617 | Measured Ambient Air Temperature Sensor Value Is Invalid. |
| MR3706 | Valve Incorporating Scr Compressed Air Has A Short To Ground. |
| MR3707 | Valve Switching Compressed Air Scr Has Short To Positive. |
| MR3709 | Valve Incorporating Scr Compressed Air Has A Circuit Break. |
| MR3817 | The Measured Values Of The Temperature Sensors On Unreliable Catalyst. |
| MR3906 | Adblue Pump Has A Short To Ground. |
| MR3907 | Adblue Pump Has A Short Circuit To Positive. |
| MR3909 | Adblue Pump Is A Circuit Break. |
| MR4024 | Internal Fault In The Control Unit |
| MR4034 | Internal Fault In The Control Unit |
| MR4035 | Internal Fault In The Control Unit |
| MR4036 | Internal Fault In The Control Unit |
| MR4037 | Internal Fault In The Control Unit |
| MR4038 | Internal Fault In The Control Unit |
| MR4039 | Starter Control (Output Stage) Faulty |
| MR4040 | Internal Fault In The Control Unit |
| MR4041 | Internal Fault In The Control Unit |
| MR4047 | Internal Fault In The Control Unit |
| MR4048 | Internal Fault In The Control Unit |
| MR4049 | Invalid Parameterization Of Proportional Valves |
| MR4050 | Internal Fault In The Control Unit |
| MR4051 | Internal Fault In The Control Unit |
| MR4052 | Internal Fault In The Control Unit |
| MR4053 | Internal Fault In The Control Unit |
| MR4054 | Internal Fault In The Control Unit |
| MR4056 | Internal Fault In The Control Unit |
| MR4058 | Mr Data Block Adjusting Engine Control Unit (Pld) Has Been Changed. |
| MR4092 | Internal Fault In The Control Unit |
| MR4149 | Engine Brake Parameterized Incorrectly. |
| MR4200 | Proportional Valve 5 Has Short To Positive. |
| MR4201 | Proportional Valve 5 Has A Short To Ground. |
| MR4202 | Proportional Valve 7 Has A Short To Ground. |
| MR4203 | Proportional Valve 7 Is A Circuit Break. |
| MR4204 | Proportional Valve 7 Has A Short Circuit To Positive. |
| Code | Description |
|---|---|
| MR4205 | Throttle Position Sensor Has A Short Circuit To Positive, A Circuit Break. |
| MR4206 | Throttle Position Sensor Has A Short To Ground. |
| MR4207 | Temperature Sensor To A Diesel Oxidation Catalyst Has A Short Circuit To Positive, A Circuit Break. |
| MR4208 | Temperature Sensor To A Diesel Oxidation Catalyst Has A Short To Ground. |
| MR4209 | Temperature Sensor For The Diesel Oxidation Catalyst Has A Short Circuit To Positive, A Circuit Break. |
| MR4210 | Temperature Sensor For The Diesel Oxidation Catalyst Has A Short To Ground. |
| MR4211 | Differential Pressure Sensor Before The Particulate Filter Has Short To Positive, A Circuit Break. |
| MR4212 | Differential Pressure Sensor In Front Of The Diesel Particulate Filter Has A Short To Ground. |
| MR4213 | Differential Pressure Sensor For The Diesel Particulate Filter Has A Short Circuit To Positive, A Circuit Break. |
| MR4214 | Differential Pressure Sensor For The Diesel Particulate Filter Has A Short To Ground. |
| MR4215 | Differential Pressure In The Particulate Filter Is Too Large. |
| MR4216 | Differential Pressure In The Particulate Filter Is Too Small. |
| MR4217 | Adjusting Throttle Deviation Is Too Large. |
| MR4218 | Set Up The Throttle Failed. |
| MR4219 | Diffuser In Adblue Dispenser Is Clogged. |
| MR4220 | Dispenser Dirty |
| MR4221 | Heating Of The Diffuser Has A Circuit Break. |
| MR4222 | Heating Of The Diffuser Has A Short To Ground. |
| MR4223 | Heating Of The Diffuser Has A Short Circuit To Positive. |
| MR4224 | Internal Fault In The Control Unit |
| MR4225 | Proportional Valve 1 Has A Number Of Short To Positive. |
| MR4226 | Proportional Valve Number 1 Has A Short To Ground. |
| MR4227 | Internal Fault In The Control Unit |
| MR4228 | No Sort Components. |
| MR4229 | Measured Value Sort Temperature Sensors (Pair A) Is Uncertain. |
| MR4230 | Measured Value Sort Temperature (Pair B) Sensors Unreliable. |
| MR4231 | Diesel Particulate Filter Is Not Installed. |
| MR4232 | The Measured Value Of The Differential Pressure Sensor In Front Of The Particulate Filter Is Uncertain. |
| MR4233 | The Measured Differential Pressure Sensor Value After The Particulate Filter Is Uncertain. |
| MR4234 | Too High Emission Of Nitrogen Oxides As A Result Of Unknown Cause (2 Threshold Value Is Exceeded) |
| MR4235 | Too High Emission Of Nitrogen Oxides Due To The Low Quality Of Adblue |
| MR4236 | Too High Vfros Nitrogen Oxides Due To Insufficient Dosing Of Adblue |
| MR4237 | Measured Value Of The Nox Sensor Is Uncertain. |
| MR4238 | The Temperature In The Particulate Filter Is Too Low. |
| MR4239 | Sensor Unit 1 In The Mr Control Unit Has A Short Circuit. |
| MR4240 | Sensor Unit 2 In The Mr Control Unit Has A Short Circuit. |
| MR4241 | Sensor Unit 1 In The Scr Module On The Frame Has A Closure. |
| MR4242 | Sensor Unit 2 In The Scr Module On The Frame Has A Closure. |
| MR4243 | Sensor Unit 3 In The Scr Module On The Frame Has A Closure. |
| MR4244 | Nox Sensor Malfunction |
| MR4245 | Faulty Structural Unit 'Of Nox Sensor'. |
| MR4246 | Too High An Initial Release Of Nitric Oxide |
| MR4247 | Faulty Constructive 'Catalyst' Node. |
| MR4248 | Poor Quality Or Insufficient Dosing Of Adblue Adblue |
| MR4249 | Too High Emission Of Nitrogen Oxides |
| MR4415 | Differential Pressure Sensor Before The Particulate Filter Has Short To Positive, A Circuit Break. |
| MR4416 | Differential Pressure Sensor In Front Of The Diesel Particulate Filter Has A Short To Ground. |
| MR4805 | Pump-Nozzle Number 1 Has Short To Positive. |
| MR4806 | Return Pump Nozzles Number 1 Has A Short To Ground. |
| MR4905 | Pump-Nozzle 2 Has A Number Of Short To Positive. |
| MR4906 | Return Of The Pump-Injector Number 2 Has A Short To Ground. |
| MR5026 | Pump-Injector Cylinder 1: The Valve Does Not Open |
| MR5027 | Pump-Injector Cylinder 1: Fault Management |
| MR5028 | Pump-Injector Cylinder 1: Short Circuit |
| MR5126 | Pump-Injector Cylinder 2: The Valve Does Not Open |
| MR5127 | Pump-Injector Cylinder 2: Control Fault |
| MR5128 | Pump-Injector 2 Short Circuit |
| MR5226 | Pump-Injector Cylinder 3: The Valve Does Not Open |
| MR5227 | Pump-Injector Cylinder 3: Fault Management |
| MR5228 | Pump-Injector Cylinder 3: Short Circuit |
| MR5326 | Pump-Injector Cylinder 4: The Valve Does Not Open |
| MR5327 | Pump-Injector Cylinder 4: Fault Management |
| MR5328 | Pump-Cylinder Injector 4 Short Circuit |
| MR5426 | Pump-Injector Cylinder 5: The Valve Does Not Open |
| MR5427 | Pump-Injector Cylinder 5: Fault Management |
| MR5428 | Pump-Injector Cylinder 5: Short Circuit |
| MR5526 | Pump-Injector Cylinder 6: The Valve Does Not Open |
| MR5527 | Pump-Injector Cylinder 6: Control Fault |
| MR5528 | Pump-Injector Cylinder 6: Short Circuit |
| MR5626 | Pump-Injector Cylinder 7: The Valve Does Not Open |
| MR5627 | Pump-Cylinder Injector 7: Control Fault |
| MR5628 | Pump-Injector Cylinder 7: Short Circuit |
| MR5726 | Pump-Injector Cylinder 8: The Valve Does Not Open |
| MR5727 | Pump-Injector Cylinder 8: Fault Management |
| MR5728 | Pump-Injector Cylinder 8: Short Circuit |
| MR5806 | Adblue Heating Pipe Has A Short To Ground. |
| MR5807 | Adblue Heating Pipe Has A Short Circuit To Positive. |
| MR5809 | Adblue Heating Pipe Has A Circuit Break. |
| MR5869 | Adblue Heating Pipe Is Defective. |
| MR5906 | Solenoid Valve For Heating Adblue Tank Has A Short To Ground. |
| MR5907 | Solenoid Valve For Heating Adblue Tank Has Short To Positive. |
| MR5909 | Magnetic Adblue Heating Valve Has A Gap Circuits. |
| MR5969 | Valve Heating Adblue Tank Is Defective. |
| MR6015 | Adblue Level Sensor Has A Short Circuit To Positive, A Circuit Break. |
| MR6016 | Adblue Level Sensor Has A Short Circuit To Ground. |
| MR6029 | Adblue Tank Fill Level Is Too Low. |
| MR6115 | Adblue Tank Temperature Sensor Has Short To Positive, A Circuit Break. |
| MR6116 | Adblue Tank Temperature Sensor Is Short To Ground. |
| MR6169 | Sensor 'Fill Rate / Temperature Of The Adblue Tank' Is Defective. |
| MR6293 | Internal Fault In The Scr Module On The Frame |
| MR6327 | Activating The Obd Lamp Broken. |
| MR6409 | Heating Flange Has A Gap Circuits. |
| MR6432 | Problem Heated Flange |
| MR6506 | Diagnostic Separator Wire Has A Short Circuit To Ground. |
| MR6564 | Diagnostic Cable Separator Has A Circuit Break Or Short Circuit To Positive. |
| MR6678 | Exhaust Gas Recirculation Valve Is Faulty. |
| MR6679 | The Temperature Difference Between The Exhaust Gases And Cooling Fluid Is Unreliable. |
| MR6720 | Adblue Pressure Is Too High. |
| MR6721 | Adblue Pressure Is Too Low. |
| MR6770 | Adblue Pressure Drop At Pump Run Too Little. |
| MR6777 | Adblue Pump Current Consumption Is Too High. |
| MR6820 | Scr Compressed Air Pressure Is Too High. |
| MR6821 | Compressed Air Pressure Is Too Low Scr. |
| MR6883 | Air Supply Scr Compressed Air System Is Broken. |
| MR6949 | Parameterization Error |
| MR6994 | Exhaust Gas Aftertreatment System Is Turned Off And The Diagnostic Program Is Active |
| MR6995 | Exhaust Gas Aftertreatment System Is Turned Off And The Diagnostic Program Is Active |
| MR7006 | Proportional Valve 1 Has A Short To Ground. |
| MR7007 | Proportional Valve 1 Has A Short Circuit To Positive. |
| MR7009 | Proportional Valve 1 Has A Circuit Break. |
| MR7106 | Solenoid Valve 3: Fan Stage 1 Has A Short To Ground. |
| MR7107 | Proportional Valve 3 Has A Short Circuit To Positive. |
| MR7109 | Solenoid Valve 3: Fan Stage 1 Is A Circuit Break. |
| MR7112 | Solenoid Valve 3: Increases The Fan Drive - No Fan Speed |
| MR7206 | Solenoid Valve 4: Fan Stage 2 Is Shorted To Ground. |
| MR7207 | Proportional Valve 4 Has A Short Circuit To Positive. |
| MR7209 | Solenoid Valve 4: Fan Stage 2 Is A Circuit Break. |
| MR7305 | Solenoid Valve 2: Brake Decompression Valve Has A Short Circuit To Positive. |
| MR7306 | Solenoid Valve 2: Brake Decompression Valve Has A Short To Ground. |
| MR7307 | Proportional Valve 2 Has A Short Circuit To Positive. |
| MR7309 | Proportional Valve 2 Has A Circuit Break. |
| MR7317 | Solenoid Valve 2: Brake Decompression Valve Has A Circuit Break Or Short Circuit To Ground. |
Fault codes categories
Gear Shift Fault Codes List
Gear Shift (GS) code will immediately identify if there are any malfunctions related to the gear shit functioning.
Learn more
Engine Control Fault Codes
MR codes will help you identify engine-related malfunctions – usually, they are closely related to the vehicle’s speed, pressure, breaking or oil pressure.
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Maintenance System Fault Codes
WS codes will help you identify maintenance system malfunctions – usually these are related to internal, temperature sensors, brake pads or oil temperature faults.
Learn more
Automatic Transmission Programming Fault Codes
ATP codes will help you identify any malfunctions related to the gearbox and indirectly indicate other malfunctions connected to the vehicle transmission.
Learn more