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Mercedes-Benz
🔴 High
Mercedes-Benz
P204F
AdBlue SCR Reductant System Performance Fault
The P204F fault on your Mercedes-Benz indicates a AdBlue SCR Reductant System Performance Fault. Your Mercedes-Benz has registered an anomaly during a diagnostic self-test, indicating the system is struggling to reach its target operating range.
Brand
Mercedes-Benz
Fault Code
P204F
Severity
🔴 High
Models
A/B/C/E/S Class, GLC, GLE, GLA, CLA, Vito, Sprinter
🛠️ Diagnostic Overview
Difficulty Level
🛠️🛠️
Medium (Moderate)
Estimated Time
⏱️ 1-2 Hours
🧰 Required Tools
- ✓ Digital Multimeter
- ✓ Socket Wrench & Hand Tools
⚠️ Possible Causes
- • Contaminated or crystallized AdBlue injector
- • Low quality AdBlue
- • Faulty NOx sensor
- • AdBlue pump failure
- • Frozen AdBlue lines
🔧 Recommended Fixes
- → Replace AdBlue injector
- → Use high-quality AdBlue
- → Replace NOx sensors
- → Test AdBlue pump
🔴 This is a high-priority fault. Have the vehicle inspected by a qualified technician as soon as possible.
🚗 Commonly Affected Vehicles
🏭 Mercedes-Benz – Other Common Fault Codes
U0100
MERCEDES U0100 Lost Communication With ECM/PCM A
🚨 Critical
P2293
MERCEDES P2293 Fuel Pressure Regulator 2 Performance
🔴 High
P219A
MERCEDES P219A Bank 1 Air-Fuel Ratio Imbalance
🟡 Medium
P2181
MERCEDES P2181 Cooling System Performance
🟡 Medium
P2096
MERCEDES P2096 Post Catalyst Fuel Trim System Too Lean
🟡 Medium
P2015
MERCEDES P2015 Intake Manifold Runner Position Sensor Circuit Range
🔴 High
P1101
MERCEDES P1101 MAF Sensor Out of Self Test Range
🟡 Medium
P0741
MERCEDES P0741 Torque Converter Clutch Circuit Performance
🟡 Medium
P0700
MERCEDES P0700 Transmission Control System Malfunction
🚨 Critical
P0600
MERCEDES P0600 Serial Communication Link Malfunction
🟡 Medium
P0507
MERCEDES P0507 Idle Control System RPM Higher Than Expected
🟡 Medium
P0500
MERCEDES P0500 Vehicle Speed Sensor Malfunction
🟡 Medium
P0456
MERCEDES P0456 EVAP System Leak Detected (very small leak)
🟡 Medium
P0455
MERCEDES P0455 EVAP System Leak Detected (large leak)
🟡 Medium
P0442
MERCEDES P0442 EVAP System Leak Detected (small leak)
🟡 Medium
P0441
MERCEDES P0441 Evaporative Emission System Incorrect Purge Flow
🟡 Medium
P0430
MERCEDES P0430 Catalyst System Efficiency Below Threshold Bank 2
🟡 Medium
P0420
MERCEDES P0420 Catalyst System Efficiency Below Threshold
🟡 Medium
P0401
MERCEDES P0401 Exhaust Gas Recirculation Flow Insufficient
🟡 Medium
P0400
MERCEDES P0400 Exhaust Gas Recirculation Flow Malfunction
🟡 Medium
P0340
MERCEDES P0340 Camshaft Position Sensor Circuit Malfunction
🟡 Medium
P0335
MERCEDES P0335 Crankshaft Position Sensor A Circuit Malfunction
🔴 High
P0325
MERCEDES P0325 Knock Sensor 1 Circuit Malfunction
🟡 Medium
P0304
MERCEDES P0304 Cylinder 4 Misfire Detected
🟡 Medium
P0303
MERCEDES P0303 Cylinder 3 Misfire Detected
🟡 Medium
P0302
MERCEDES P0302 Cylinder 2 Misfire Detected
🟡 Medium
P0301
MERCEDES P0301 Cylinder 1 Misfire Detected
🔴 High
P0300
MERCEDES P0300 Random/Multiple Cylinder Misfire Detected
🚨 Critical
P0299
MERCEDES P0299 Turbocharger Underboost Condition
🚨 Critical
P0234
MERCEDES P0234 Turbocharger Overboost Condition
🚨 Critical
P0175
MERCEDES P0175 System Too Rich Bank 2
🟡 Medium
P0174
MERCEDES P0174 System Too Lean Bank 2
🔴 High
P0172
MERCEDES P0172 System Too Rich Bank 1
🟡 Medium
P0171
MERCEDES P0171 System Too Lean Bank 1
🔴 High
P0141
MERCEDES P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
🟡 Medium
P0135
MERCEDES P0135 O2 Sensor Heater Circuit Malfunction
🟡 Medium
P0133
MERCEDES P0133 O2 Sensor Circuit Slow Response
🟡 Medium
P0130
MERCEDES P0130 O2 Sensor Circuit Malfunction
🔴 High
P0128
MERCEDES P0128 Coolant Thermostat Malfunction
🟡 Medium
P0113
MERCEDES P0113 Intake Air Temperature Circuit High Input
🟡 Medium
P0102
MERCEDES P0102 Mass Air Flow Circuit Low Input
🟡 Medium
P0101
MERCEDES P0101 Mass Air Flow Sensor Circuit Range/Performance
🟡 Medium
P0087
MERCEDES P0087 Fuel Rail/System Pressure - Too Low
🚨 Critical
P0012
MERCEDES P0012 A Camshaft Position Timing Over-Retarded
🟡 Medium
P0011
MERCEDES P0011 A Camshaft Position Timing Over-Advanced
🟡 Medium
P0010
MERCEDES P0010 A Camshaft Position Actuator Circuit
🟡 Medium
P2279
Intake Air System Leak (M271/M272/M274)
🟡 Medium
P016B
Camshaft/Crankshaft Correlation Fault (OM651)
🔴 High
P0088
Fuel Rail Pressure Too High (OM642 V6 Diesel)
🔴 High
B1000
Airbag Control Module Fault / Crash Data Stored
🔴 High
C1102
ESP Control Module: Integrated Sensor Cluster Fault
🔴 High
P0016
Crankshaft/Camshaft Misalignment (M270/M274)
🔴 High
P2047
MERCEDES P2047 Reductant Injection Valve Circuit
🔴 High
P229F
MERCEDES P229F NOx Sensor Circuit Range (Bank 1 Sensor 2)
🔴 High
P0101
MERCEDES P0101 MAF Sensor Plausibility
🔴 High
P0087
MERCEDES P0087 Fuel Rail Pressure too Low
🔴 High
P0299
MERCEDES P0299 Turbocharger Underboost
🔴 High
P2509
MERCEDES P2509 ECM/PCM Power Input Signal Intermittent
🔴 High
C1000
MERCEDES C1000 ABS/ESP Control Module Internal Fault
🔴 High
B1000
MERCEDES B1000 SRS Control Module Internal Fault
🔴 High
P2002
MERCEDES P2002 DPF Efficiency below Threshold
🔴 High
P0600
MERCEDES P0600 CAN Bus Communication Error
🔴 High
P0032
MERCEDES P0032 HO2S Heater Control Circuit High (Bank 1 Sensor 1)
🟢 Low
P0037
MERCEDES P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
🟡 Medium
P0038
MERCEDES P0038 HO2S Heater Control Circuit High (Bank 1 Sensor 2)
🔴 High
P0051
MERCEDES P0051 HO2S Heater Control Circuit Low (Bank 2 Sensor 1)
🟢 Low
P0057
MERCEDES P0057 HO2S Heater Control Circuit Low (Bank 2 Sensor 2)
🟡 Medium
P0058
MERCEDES P0058 HO2S Heater Control Circuit High (Bank 2 Sensor 2)
🟡 Medium
P0103
MERCEDES P0103 Mass or Volume Air Flow Circuit High Input
🟢 Low
P0107
MERCEDES P0107 Manifold Absolute Pressure/Barometric Pressure Circuit Low Input
🟢 Low
P0108
MERCEDES P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input
🚨 Critical
P0112
MERCEDES P0112 Intake Air Temperature Circuit Low Input
🚨 Critical
P0117
MERCEDES P0117 Engine Coolant Temperature Circuit Low Input
🟡 Medium
P0118
MERCEDES P0118 Engine Coolant Temperature Circuit High Input
🟡 Medium
P0122
MERCEDES P0122 Throttle/Pedal Position Sensor/Switch A Circuit Low Input
🔴 High
P0123
MERCEDES P0123 Throttle/Pedal Position Sensor/Switch A Circuit High Input
🔴 High
P0125
MERCEDES P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control
🔴 High
P0131
MERCEDES P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
🟡 Medium
P0132
MERCEDES P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
🟡 Medium
P0134
MERCEDES P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
🟢 Low
P0137
MERCEDES P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
🟡 Medium
P0138
MERCEDES P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
🟡 Medium
P0151
MERCEDES P0151 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)
🔴 High
P0152
MERCEDES P0152 O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)
🟢 Low
P0157
MERCEDES P0157 O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
🟢 Low
P0158
MERCEDES P0158 O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
🟡 Medium
P0200
MERCEDES P0200 Injector Circuit Malfunction
🔴 High
P0231
MERCEDES P0231 Fuel Pump Secondary Circuit Low
🔴 High
P0232
MERCEDES P0232 Fuel Pump Secondary Circuit High
🟡 Medium
P0327
MERCEDES P0327 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)
🟢 Low
P0328
MERCEDES P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
🟢 Low
P0332
MERCEDES P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
🔴 High
P0333
MERCEDES P0333 Knock Sensor 2 Circuit High Input (Bank 2)
🔴 High
P0440
MERCEDES P0440 Evaporative Emission Control System Malfunction
🔴 High
P0443
MERCEDES P0443 Evaporative Emission System Purge Control Valve Circuit
🟢 Low
P0446
MERCEDES P0446 Evaporative Emission System Vent Control Circuit Malfunction
🟡 Medium
P0451
MERCEDES P0451 Evaporative Emission System Pressure Sensor Range/Performance
🟡 Medium
P0452
MERCEDES P0452 Evaporative Emission System Pressure Sensor Low Input
🚨 Critical
P0453
MERCEDES P0453 Evaporative Emission System Pressure Sensor High Input
🔴 High
P0462
MERCEDES P0462 Fuel Level Sensor Circuit Low Input
🟢 Low
P0463
MERCEDES P0463 Fuel Level Sensor Circuit High Input
🟡 Medium
P0502
MERCEDES P0502 Vehicle Speed Sensor Circuit Low Input
🟢 Low
P0503
MERCEDES P0503 Vehicle Speed Sensor Intermittent/Erratic/High
🚨 Critical
P0505
MERCEDES P0505 Idle Control System Malfunction
🟡 Medium
P0506
MERCEDES P0506 Idle Control System RPM Lower Than Expected
🚨 Critical
P0562
MERCEDES P0562 System Voltage Low
🚨 Critical
P0563
MERCEDES P0563 System Voltage High
🟢 Low
P0601
MERCEDES P0601 Internal Control Module Memory Check Sum Error
🟢 Low
P0603
MERCEDES P0603 Internal Control Module Keep Alive Memory (KAM) Error
🔴 High
P0604
MERCEDES P0604 Internal Control Module Random Access Memory (RAM) Error
🟢 Low
P0605
MERCEDES P0605 Internal Control Module Read Only Memory (ROM) Error
🟡 Medium
P0606
MERCEDES P0606 ECM/PCM Processor Fault
🔴 High
P0705
MERCEDES P0705 Transmission Range Sensor Circuit Malfunction (PRNDL Input)
🚨 Critical
P0706
MERCEDES P0706 Transmission Range Sensor Circuit Range/Performance
🚨 Critical
P0715
MERCEDES P0715 Input/Turbine Speed Sensor Circuit Malfunction
🔴 High
P0720
MERCEDES P0720 Output Speed Sensor Circuit Malfunction
🟢 Low
P0722
MERCEDES P0722 Output Speed Sensor No Signal
🟢 Low
P0731
MERCEDES P0731 Gear 1 Incorrect Ratio
🚨 Critical
P0732
MERCEDES P0732 Gear 2 Incorrect Ratio
🟢 Low