Comprehensive Guide to Mercedes-Benz Diesel Engine Codes
Mercedes-Benz diesel engine codes can seem like a daunting language, but understanding them is vital for anyone working on or owning these vehicles. This guide from CARDIAGTECH.NET provides a detailed breakdown to help you diagnose issues effectively.
Mercedes-Benz diesel engine codes serve as vital indicators of your vehicle’s health. CARDIAGTECH.NET offers expert guidance and tools to help you decipher these codes, ensuring efficient diagnostics and repairs. By understanding these codes, you can accurately pinpoint problems, maintain your vehicle’s performance, and extend its lifespan, all while minimizing downtime and repair costs.
1. Decoding Mercedes-Benz Diesel Engine Fault Codes: An Overview
Do you want to understand what those Mercedes-Benz diesel engine codes really mean? Diagnostic Trouble Codes (DTCs) are like a secret language your car uses to tell you what’s wrong. They’re essential for diagnosing and fixing issues in modern vehicles, especially sophisticated Mercedes-Benz models.
These codes are generated by the vehicle’s onboard computer when it detects a problem. Addressing these issues quickly can save you from more costly repairs down the line.
1.1. Why Are Fault Codes Important?
Fault codes are crucial for several reasons:
- Accuracy: They pinpoint the exact system or component that is malfunctioning.
- Efficiency: They reduce diagnostic time, allowing technicians to quickly identify and address the problem.
- Cost-Effectiveness: By accurately diagnosing the issue, unnecessary repairs and replacements can be avoided.
According to a study by the National Institute for Automotive Service Excellence (ASE), using diagnostic tools and fault codes can reduce repair times by up to 40%. This efficiency translates to significant cost savings for both the technician and the vehicle owner.
1.2. How to Access Fault Codes
Accessing fault codes requires diagnostic equipment that can connect to your Mercedes-Benz’s On-Board Diagnostics (OBD-II) port. This port is typically located under the dashboard. Once connected, the diagnostic tool will read and display any stored fault codes.
There are several types of diagnostic tools available:
- Basic Code Readers: These tools are inexpensive and can read basic fault codes.
- Advanced Scan Tools: These provide more in-depth information, including live data, freeze frame data, and the ability to perform advanced diagnostics.
- Mercedes-Benz Specific Scanners: These are designed specifically for Mercedes-Benz vehicles and offer the most comprehensive diagnostic capabilities.
For professionals, investing in a Mercedes-Benz specific scanner from CARDIAGTECH.NET can significantly enhance their diagnostic accuracy and efficiency.
1.3 Understanding the Structure of Mercedes-Benz Fault Codes
What is the anatomy of a Mercedes-Benz fault code? These codes typically consist of a letter followed by four or five numbers. Here’s a breakdown:
-
First Character (Letter):
- P: Powertrain (Engine, Transmission)
- B: Body (e.g., Airbags, Central Locking)
- C: Chassis (e.g., ABS, ESP)
- U: Network Communication
-
Second Character (Number):
- 0: Generic OBD-II Code
- 1, 2, 3: Manufacturer-Specific Code
-
Remaining Characters (Numbers):
- Indicate the specific fault within the system.
Alt text: A close-up view of a diagnostic scanner displaying various Mercedes-Benz fault codes, showing their structure and categories.
2. Common Mercedes-Benz Diesel Engine Codes and Their Meanings
What are some of the most frequently encountered fault codes in Mercedes-Benz diesel engines? Here are some common codes, their meanings, and potential solutions:
2.1. P0400 Series: Exhaust Gas Recirculation (EGR) Issues
The P0400 series of codes relates to the Exhaust Gas Recirculation (EGR) system. The EGR system is designed to reduce NOx emissions by recirculating a portion of the exhaust gas back into the engine’s intake.
| Mercedes Fault Code | Fault Code Meaning | Possible Causes |
|---|---|---|
| P0466 | Purge Flow Sensor Circuit Range/Performance | Faulty purge flow sensor, vacuum leaks, blocked or restricted purge lines. |
| P0467 | Purge Flow Sensor Circuit Low Input | Shorted or open circuit in the purge flow sensor wiring, faulty purge flow sensor, ECM issue. |
| P0468 | Purge Flow Sensor Circuit High Input | Open or shorted circuit in the purge flow sensor wiring, faulty purge flow sensor, ECM issue. |
| P0469 | Purge Flow Sensor Circuit Intermittent | Loose connections, corroded terminals, intermittent failures within the purge flow sensor. |
| P0470 | Exhaust Pressure Sensor Malfunction | Faulty exhaust pressure sensor, damaged wiring, corroded connectors. |
| P0471 | Exhaust Pressure Sensor Range/Performance | Blocked or damaged exhaust pressure sensor tube, exhaust leaks, faulty sensor. |
| P0472 | Exhaust Pressure Sensor Low | Shorted circuit in the exhaust pressure sensor wiring, faulty sensor, ECM issue. |
| P0473 | Exhaust Pressure Sensor High | Open circuit in the exhaust pressure sensor wiring, faulty sensor, ECM issue. |
| P0474 | Exhaust Pressure Sensor Intermittent | Intermittent sensor failures, loose connections, corroded terminals. |
| P0475 | Exhaust Pressure Control Valve Malfunction | Faulty exhaust pressure control valve, damaged wiring, vacuum leaks. |
| P0476 | Exhaust Pressure Control Valve Range/Performance | Blocked or damaged exhaust pressure control valve, exhaust leaks, faulty sensor. |
| P0477 | Exhaust Pressure Control Valve Low | Shorted circuit in the exhaust pressure control valve wiring, faulty valve, ECM issue. |
| P0478 | Exhaust Pressure Control Valve High | Open circuit in the exhaust pressure control valve wiring, faulty valve, ECM issue. |
| P0479 | Exhaust Pressure Control Valve Intermittent | Intermittent valve failures, loose connections, corroded terminals. |
| P0480 | Cooling Fan 1 Control Circuit Malfunction | Faulty cooling fan relay, damaged wiring, faulty fan motor. |
| P0481 | Cooling Fan 2 Control Circuit Malfunction | Faulty cooling fan relay, damaged wiring, faulty fan motor. |
| P0482 | Cooling Fan 3 Control Circuit Malfunction | Faulty cooling fan relay, damaged wiring, faulty fan motor. |
| P0483 | Cooling Fan Rationality Check Malfunction | Faulty fan speed sensor, ECM issue, incorrect fan operation. |
| P0484 | Cooling Fan Circuit Over Current | Shorted fan motor, faulty relay, wiring issues. |
| P0485 | Cooling Fan Power/Ground Circuit Malfunction | Corroded or loose ground connections, damaged power wires, faulty relay. |
Troubleshooting Tips:
- Inspect EGR Valve: Check for carbon buildup and ensure it opens and closes freely.
- Check Vacuum Lines: Look for cracks, leaks, or blockages in the vacuum lines connected to the EGR valve.
- Test EGR Solenoid: Use a multimeter to test the solenoid’s resistance.
- Clean EGR Passages: Remove carbon deposits from the EGR passages in the intake manifold.
2.2. P0500 Series: Vehicle Speed Sensor (VSS) Issues
The P0500 series of codes relates to the Vehicle Speed Sensor (VSS). The VSS provides the vehicle’s speed information to the engine control unit (ECU), transmission control unit (TCU), and other systems.
| Mercedes Fault Code | Fault Code Meaning | Possible Causes |
|---|---|---|
| P0500 | Vehicle Speed Sensor Malfunction | Faulty VSS, damaged wiring, corroded connectors, ECU issue. |
| P0501 | Vehicle Speed Sensor Range/Performance | Incorrect VSS installation, wrong VSS type, ECU issue. |
| P0502 | Vehicle Speed Sensor Low Input | Shorted circuit in the VSS wiring, faulty sensor, ECU issue. |
| P0503 | Vehicle Speed Sensor Intermittent/Erratic/High | Loose connections, intermittent sensor failures, electromagnetic interference. |
| P0505 | Idle Control System Malfunction | Faulty idle air control (IAC) valve, vacuum leaks, throttle body issues. |
| P0506 | Idle Control System RPM Lower Than Expected | Vacuum leaks, carbon buildup in the throttle body, faulty IAC valve. |
| P0507 | Idle Control System RPM Higher Than Expected | Vacuum leaks, faulty IAC valve, incorrect throttle position sensor (TPS) adjustment. |
| P0510 | Closed Throttle Position Switch Malfunction | Faulty TPS, incorrect TPS adjustment, damaged wiring. |
| P0520 | Engine Oil Pressure Sensor/Switch Circuit Malfunction | Faulty oil pressure sensor, damaged wiring, low oil level. |
| P0521 | Engine Oil Pressure Sensor/Switch Circuit Range/Performance | Incorrect oil viscosity, clogged oil filter, faulty oil pump. |
| P0522 | Engine Oil Pressure Sensor/Switch Circuit Low Voltage | Shorted circuit in the oil pressure sensor wiring, faulty sensor. |
| P0523 | Engine Oil Pressure Sensor/Switch Circuit High Voltage | Open circuit in the oil pressure sensor wiring, faulty sensor. |
| P0530 | A/C Refrigerant Pressure Sensor Circuit Malfunction | Faulty A/C pressure sensor, damaged wiring, low refrigerant level. |
| P0531 | A/C Refrigerant Pressure Sensor Circuit Range/Performance | Incorrect refrigerant charge, faulty sensor. |
| P0532 | A/C Refrigerant Pressure Sensor Circuit Low Input | Shorted circuit in the A/C pressure sensor wiring, faulty sensor. |
| P0533 | A/C Refrigerant Pressure Sensor Circuit High Input | Open circuit in the A/C pressure sensor wiring, faulty sensor. |
| P0534 | Air Conditioner Refrigerant Charge Loss | Leaks in the A/C system, faulty compressor. |
| P0550 | Power Steering Pressure Sensor Circuit Malfunction | Faulty power steering pressure sensor, damaged wiring, low power steering fluid level. |
| P0551 | Power Steering Pressure Sensor Circuit Range/Performance | Incorrect power steering fluid level, faulty sensor. |
| P0552 | Power Steering Pressure Sensor Circuit Low Input | Shorted circuit in the power steering pressure sensor wiring, faulty sensor. |
| P0553 | Power Steering Pressure Sensor Circuit High Input | Open circuit in the power steering pressure sensor wiring, faulty sensor. |
| P0554 | Power Steering Pressure Sensor Circuit Intermittent | Loose connections, intermittent sensor failures. |
Troubleshooting Tips:
- Inspect VSS: Check for physical damage and ensure it is securely mounted.
- Check Wiring: Look for damaged or corroded wiring and connectors.
- Test VSS Signal: Use a multimeter or oscilloscope to check the VSS signal while driving.
- Verify Wheel Speed Sensors: Ensure the wheel speed sensors are functioning correctly, as they can affect the VSS signal.
2.3. P0600 Series: Control Module Issues
The P0600 series of codes indicates problems with the vehicle’s control modules, such as the Engine Control Module (ECM) or Transmission Control Module (TCM).
| Mercedes Fault Code | Fault Code Meaning | Possible Causes |
|---|---|---|
| P0600 | Serial Communication Link Malfunction | Wiring issues, faulty control modules, CAN bus problems. |
| P0601 | Internal Control Module Memory Check Sum Error | Faulty ECM/PCM, corrupted memory. |
| P0602 | Control Module Programming Error | Incorrect programming, corrupted software. |
| P0603 | Internal Control Module Keep Alive Memory (KAM) Error | Low battery voltage, faulty ECM/PCM. |
| P0604 | Internal Control Module Random Access Memory (RAM) Error | Faulty ECM/PCM. |
| P0605 | Internal Control Module Read Only Memory (ROM) Error | Faulty ECM/PCM. |
| P0606 | PCM Processor Fault | Faulty ECM/PCM. |
| P0608 | Control Module VSS Output “A” Malfunction | Wiring issues, faulty ECM/PCM. |
| P0609 | Control Module VSS Output “B” Malfunction | Wiring issues, faulty ECM/PCM. |
| P0620 | Generator Control Circuit Malfunction | Faulty alternator, wiring issues, faulty ECM/PCM. |
| P0621 | Generator Lamp “L” Control Circuit Malfunction | Wiring issues, faulty alternator, faulty ECM/PCM. |
| P0622 | Generator Field “F” Control Circuit Malfunction | Wiring issues, faulty alternator, faulty ECM/PCM. |
| P0650 | Malfunction Indicator Lamp (MIL) Control Circuit Malfunction | Wiring issues, faulty ECM/PCM. |
| P0654 | Engine RPM Output Circuit Malfunction | Wiring issues, faulty ECM/PCM. |
| P0655 | Engine Hot Lamp Output Control Circuit Malfunction | Wiring issues, faulty ECM/PCM. |
| P0656 | Fuel Level Output Circuit Malfunction | Wiring issues, faulty ECM/PCM. |
Troubleshooting Tips:
- Check Battery Voltage: Ensure the battery voltage is within the specified range.
- Inspect Wiring and Connectors: Look for damaged or corroded wiring and connectors.
- Test Power and Ground: Verify that the control module is receiving proper power and ground.
- Reflash or Replace the Control Module: In some cases, reflashing the control module with updated software or replacing it may be necessary.
2.4. P0700 Series: Transmission Issues
The P0700 series of codes indicates problems within the transmission system. These codes can range from minor issues to severe mechanical failures.
| Mercedes Fault Code | Fault Code Meaning | Possible Causes |
|---|---|---|
| P0700 | Transmission Control System Malfunction | Internal transmission issues, faulty sensors, wiring problems. |
| P0701 | Transmission Control System Range/Performance | Low transmission fluid, internal transmission issues, faulty sensors. |
| P0702 | Transmission Control System Electrical | Wiring issues, faulty solenoids, internal transmission issues. |
| P0703 | Torque Converter/Brake Switch B Circuit Malfunction | Faulty brake switch, wiring issues. |
| P0704 | Clutch Switch Input Circuit Malfunction | Faulty clutch switch, wiring issues. |
| P0705 | Transmission Range Sensor Circuit malfunction (PRNDL Input) | Faulty transmission range sensor, wiring issues, incorrect adjustment. |
| P0706 | Transmission Range Sensor Circuit Range/Performance | Incorrect sensor adjustment, internal transmission issues, wiring problems. |
| P0707 | Transmission Range Sensor Circuit Low Input | Shorted circuit in the transmission range sensor wiring, faulty sensor. |
| P0708 | Transmission Range Sensor Circuit High Input | Open circuit in the transmission range sensor wiring, faulty sensor. |
| P0709 | Transmission Range Sensor Circuit Intermittent | Loose connections, intermittent sensor failures, wiring problems. |
| P0710 | Transmission Fluid Temperature Sensor Circuit Malfunction | Faulty transmission fluid temperature sensor, wiring issues. |
| P0711 | Transmission Fluid Temperature Sensor Circuit Range/Performance | Low transmission fluid, overheating, faulty sensor. |
| P0712 | Transmission Fluid Temperature Sensor Circuit Low Input | Shorted circuit in the transmission fluid temperature sensor wiring, faulty sensor. |
| P0713 | Transmission Fluid Temperature Sensor Circuit High Input | Open circuit in the transmission fluid temperature sensor wiring, faulty sensor. |
| P0714 | Transmission Fluid Temperature Sensor Circuit Intermittent | Loose connections, intermittent sensor failures, wiring problems. |
| P0715 | Input/Turbine Speed Sensor Circuit Malfunction | Faulty input/turbine speed sensor, wiring issues. |
| P0716 | Input/Turbine Speed Sensor Circuit Range/Performance | Internal transmission issues, faulty sensor, wiring problems. |
| P0717 | Input/Turbine Speed Sensor Circuit No Signal | Faulty input/turbine speed sensor, wiring issues. |
| P0718 | Input/Turbine Speed Sensor Circuit Intermittent | Loose connections, intermittent sensor failures, wiring problems. |
| P0719 | Torque Converter/Brake Switch B Circuit Low | Shorted circuit in the brake switch wiring, faulty switch. |
Troubleshooting Tips:
- Check Transmission Fluid Level and Condition: Ensure the transmission fluid is at the correct level and is not contaminated.
- Inspect Wiring and Connectors: Look for damaged or corroded wiring and connectors.
- Test Transmission Sensors: Use a diagnostic tool to monitor the transmission sensor data.
- Perform a Transmission Scan: Use a diagnostic tool to perform a comprehensive scan of the transmission system.
2.5. P0800 Series: Transmission Control System (TCS) Issues
The P0800 series focuses on issues within the Transmission Control System (TCS), which manages various functions such as shift patterns and torque converter lockup.
| Mercedes Fault Code | Fault Code Meaning | Possible Causes |
|---|---|---|
| P0801 | Reverse Inhibit Control Circuit Malfunction | Faulty reverse inhibit solenoid, wiring issues, TCM problem. |
| P0803 | 1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction | Faulty skip shift solenoid, wiring issues, ECM/TCM problem. |
| P0804 | 1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction | Wiring issues, faulty bulb, ECM/TCM problem. |
| P0805 | Clutch Position Sensor Circuit Malfunction | Faulty clutch position sensor, wiring issues, ECM/TCM problem. |
| P0806 | Clutch Position Sensor Circuit Range/Performance | Misadjusted clutch position sensor, mechanical issues with the clutch linkage, ECM/TCM problem. |
| P0807 | Clutch Position Sensor Circuit Low | Shorted circuit in the clutch position sensor wiring, faulty sensor, ECM/TCM problem. |
| P0808 | Clutch Position Sensor Circuit High | Open circuit in the clutch position sensor wiring, faulty sensor, ECM/TCM problem. |
| P0809 | Clutch Position Sensor Circuit Intermittent Ckt | Loose connections, intermittent sensor failures, wiring issues. |
| P0810 | Clutch Position Control Malfunction | Mechanical issues with the clutch, hydraulic problems, ECM/TCM issue. |
| P0811 | Clutch Slippage Excessive | Worn clutch, hydraulic problems, ECM/TCM issue. |
| P0812 | Reverse Input Circuit Malfunction | Wiring issues, faulty switch, ECM/TCM problem. |
| P0813 | Reverse Output Circuit Malfunction | Wiring issues, faulty relay, ECM/TCM problem. |
| P0814 | Trans Range Display Circuit Malfunction | Wiring issues, faulty display, ECM/TCM problem. |
| P0815 | Upshift Switch Circuit Malfunction | Faulty switch, wiring issues, ECM/TCM problem. |
| P0816 | Downshift Switch Circuit Malfunction | Faulty switch, wiring issues, ECM/TCM problem. |
| P0817 | Starter Disable Circuit | Wiring issues, faulty relay, ECM/TCM problem. |
| P0818 | Driveline Disconn. Switch Input | Faulty switch, wiring issues, ECM/TCM problem. |
| P0820 | Gear Lever X-Y Sensor Circuit | Faulty sensor, wiring issues, ECM/TCM problem. |
| P0821 | Gear Lever X Sensor Circuit | Faulty sensor, wiring issues, ECM/TCM problem. |
| P0822 | Gear Lever Y Sensor Circuit | Faulty sensor, wiring issues, ECM/TCM problem. |
| P0823 | Gear Lever X Sensor Circuit Intermittent Ckt | Loose connections, intermittent sensor failures, wiring issues. |
| P0824 | Gear Lever Y Sensor Circuit Intermittent Ckt | Loose connections, intermittent sensor failures, wiring issues. |
| P0830 | Clutch Position Switch A Circuit Malfunction | Faulty switch, wiring issues, ECM/TCM problem. |
| P0831 | Clutch Position Switch A Circuit Low | Shorted circuit in the switch wiring, faulty switch, ECM/TCM problem. |
| P0832 | Clutch Position Switch A Circuit High | Open circuit in the switch wiring, faulty switch, ECM/TCM problem. |
| P0833 | Clutch Position Switch B Circuit Malfunction | Faulty switch, wiring issues, ECM/TCM problem. |
| P0834 | Clutch Position Switch B Circuit Low | Shorted circuit in the switch wiring, faulty switch, ECM/TCM problem. |
| P0835 | Clutch Position Switch B Circuit High | Open circuit in the switch wiring, faulty switch, ECM/TCM problem. |
| P0836 | 4 Wheel Drive Switch Circuit Malfunction | Faulty switch, wiring issues, transfer case control module (TCCM) problem. |
| P0837 | 4 Wheel Drive Switch CKT Range/Perf | Misadjusted switch, mechanical issues with the 4WD system, TCCM problem. |
| P0838 | 4 Wheel Drive Switch Circuit Low | Shorted circuit in the switch wiring, faulty switch, TCCM problem. |
| P0839 | 4 Wheel Drive Switch Circuit High | Open circuit in the switch wiring, faulty switch, TCCM problem. |
| P0840 | Trans Fluid Press Sensor/Switch A Circuit Malfunction | Faulty sensor, wiring issues, TCM problem. |
| P0841 | Trans Fluid Press Sensor/Switch A CKT Range/Perf | Incorrect fluid level, faulty sensor, mechanical issues with the transmission, TCM problem. |
| P0842 | Trans Fluid Press Sensor/Switch A Circuit Low | Shorted circuit in the sensor wiring, faulty sensor, TCM problem. |
| P0843 | Trans Fluid Press Sensor/Switch A Circuit High | Open circuit in the sensor wiring, faulty sensor, TCM problem. |
| P0844 | Trans Fluid Press Sensor/Switch A CKT Intermittent | Loose connections, intermittent sensor failures, wiring issues. |
| P0845 | Trans Fluid Press Sensor/Switch B Circuit Malfunction | Faulty sensor, wiring issues, TCM problem. |
| P0846 | Trans Fluid Press Sensor/Switch B CKT Range/Perf | Incorrect fluid level, faulty sensor, mechanical issues with the transmission, TCM problem. |
| P0847 | Trans Fluid Press Sensor/Switch B Circuit Low | Shorted circuit in the sensor wiring, faulty sensor, TCM problem. |
| P0848 | Trans Fluid Press Sensor/Switch B Circuit High | Open circuit in the sensor wiring, faulty sensor, TCM problem. |
| P0849 | Trans Fluid Press Sensor/Switch B CKT Intermittent | Loose connections, intermittent sensor failures, wiring issues. |
Troubleshooting Tips:
- Inspect the Transmission Control Module (TCM): Check for any signs of physical damage or corrosion.
- Verify Wiring and Connections: Ensure all wiring and connectors are in good condition and properly connected.
- Test the Switches and Sensors: Use a multimeter or diagnostic tool to check the functionality of the switches and sensors in the TCS.
- Check Fluid Levels and Condition: Ensure that the transmission fluid is at the correct level and is free from contamination.
2.6. P1000-P2000 Series: Manufacturer-Specific Codes
The P1000-P2000 range contains manufacturer-specific codes that are unique to Mercedes-Benz. These codes often relate to more complex or specialized systems within the vehicle.
| Mercedes Fault Code | Fault Code Meaning | Possible Causes |
|---|---|---|
| P1000 | Electronic Gear Selector Module: Defective N15/5 | Faulty gear selector module, wiring issues, internal module failure. |
| P1228 | Yet unknown code on 1997 C 220 CDI | Requires further diagnosis; consult Mercedes-Benz specific resources. |
| P1386 | Knock control | Faulty knock sensor, wiring issues, engine problems. |
| P1570 | Intermittent No-Start Immobilizer Module | Faulty immobilizer module, key issues, wiring problems. |
| P1747 | Electronic Gear Selector Module: Defective Interaction of CAN with control unit A1(instrument cluster) | CAN bus issues, faulty gear selector module, instrument cluster problems. |
| P1750 | Electronic Gear Selector Module: Very low control unit supply voltage | Low battery voltage, wiring issues, faulty gear selector module. |
| P1832 | Electronic Gear Selector Module: SHORT in circuit N15/5 output stage | Short circuit in the gear selector module, wiring issues. |
| P1910 | Electronic Gear Selector Module: Control Unit over voltage | Overvoltage condition, wiring issues, voltage regulator problems. |
| P1912 | Electronic Gear Selector Module: Weak touch push button voltage | Faulty push buttons, wiring issues, gear selector module problem. |
| P2000 | NOx Trap Efficiency Below Threshold (Bank 1) | Faulty NOx sensor, exhaust leaks, catalytic converter issues. |
| P2001 | NOx Trap Efficiency Below Threshold (Bank 2) | Faulty NOx sensor, exhaust leaks, catalytic converter issues. |
| P2003 | Particulate Trap Efficiency Below Threshold (Bank 1) | Clogged diesel particulate filter (DPF), faulty sensors, exhaust leaks. |
| P2004 | Particulate Trap Efficiency Below Threshold (Bank 2) | Clogged diesel particulate filter (DPF), faulty sensors, exhaust leaks. |
| P2031 | Exhaust Gas Temperature Sensor Circuit (Bank 1 Sensor 2) | Faulty exhaust gas temperature sensor, wiring issues. |
| P2032 | Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 2) | Shorted circuit in the exhaust gas temperature sensor wiring, faulty sensor. |
| P2033 | Exhaust Gas Temperature Sensor Circuit High (Bank 1 Sensor 2) | Open circuit in the exhaust gas temperature sensor wiring, faulty sensor. |
| P2080 | Exhaust Gas Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 1) | Faulty exhaust gas temperature sensor, exhaust leaks, wiring issues. |
| P2081 | Exhaust Gas Temperature Sensor Circuit Intermittent (Bank 1 Sensor 1) | Loose connections, intermittent sensor failures, wiring issues. |
| P2100 | Throttle Actuator Control Motor Circuit/Open | Faulty throttle actuator motor, wiring issues. |
| P2101 | Throttle Actuator Control Motor Circuit Range/Performance | Throttle body issues, faulty throttle actuator motor, wiring problems. |
| P2208 | Transmission: The speed of Y3/6n2 to Y3/6n3 is excessive | Internal transmission issues, faulty speed sensors, TCM problems. |
Troubleshooting Tips:
- Consult Mercedes-Benz Specific Resources: Refer to the Mercedes-Benz service manual or online database for detailed information about the specific code.
- Use Advanced Diagnostic Tools: Utilize advanced scan tools that can provide live data and perform specialized tests.
- Check Wiring and Connectors: Inspect the wiring and connectors associated with the affected system or component.
- Test Components: Perform component-level testing to identify faulty parts.
2.7. Specific Fault Code Examples
Let’s examine a couple of specific fault codes in more detail:
2.7.1. Mercedes Fault Code: P261F71
| Detail | Description |
|---|---|
| Fault Code Meaning | The output for circulation pump has a malfunction. Actuator is blocked. |
| Known Problem Of | Mercedes Sprinter Vans |
| Likely Causes | Coolant intrusion into vacuum system via the water pump. |
| What’s Happening? | On model OM651 4 Cylinder Diesel Engine the coolant water pump is vacuum actuated. Internal seal failure allows coolant to enter the vacuum system. |
| Possible Symptoms | Check Engine Light, little to no acceleration, coolant leak, brake pedal pressure issues, engine overheating. |
| Parts That Could Need Replacement | Water Pump, Coolant, Seals, Tubes, Hoses, Vacuum Actuators, Vacuum Pump |
| System(s) Affected | Engine, Cooling System, Vacuum System, Turbocharging, Brake System |
| Severity | Can be very severe if left unfixed. Repair requires MASTER LEVEL Technician and not something for the DIYer. |
2.7.2. Mercedes Fault Code: P126A00 OM642 Engine Oil Cooler Leak
| Detail | Description |
|---|---|
| Fault Code Meaning | Intake Port Shutoff Actuator is faulty. |
| Known Problem Of | Mercedes Sprinter Vans |
| Likely Causes | Failure of component: intake manifolds, or the intake manifold actuator motor. |
| What’s Happening? | Over time the inside of the intake manifolds get clogged with EGR soot, causing the intake swirl flaps to stick, binding the motor. |
| Possible Symptoms | Check Engine Light and or a severe loss of acceleration. |
| Parts That Could Need Replacement | Intake manifolds, intake manifold actuator motor. |
| System(s) Affected | Engine |
| Severity | Can be very severe if left unfixed. Repair requires MASTER LEVEL Technician and not something for the DIYer. |
3. Body, Chassis, and Communication Fault Codes
Beyond engine-related codes, Mercedes-Benz vehicles also generate fault codes related to the body, chassis, and communication systems.
3.1. Body (B-Level) Fault Codes
Body fault codes (B-codes) relate to components and systems within the vehicle’s body, such as airbags, central locking, and lighting.
| Mercedes Fault
