What Do Mercedes OBD2 Codes Mean and How to Troubleshoot Them?

Mercedes OBD2 codes are your car’s way of telling you something isn’t right. In this guide from OBD2-SCANNER.EDU.VN, we’ll break down what these codes mean, how to use an OBD2 scanner to read them, and how to start troubleshooting. We aim to equip you with the knowledge to understand your Mercedes better and take appropriate action. Understand how to read your car’s diagnostic codes for quick fixes.

1. Understanding Mercedes OBD2 Codes

Mercedes-Benz, like all modern vehicles, utilizes an On-Board Diagnostics system (OBD2) to monitor various vehicle systems. When a problem arises, the system generates a Diagnostic Trouble Code (DTC), commonly referred to as an OBD2 code. These codes can range from minor issues like a loose gas cap to more severe problems such as engine misfires or transmission failures. OBD2 codes are standardized across all makes and models, but Mercedes-Benz may have specific interpretations or related issues that are unique to its vehicles.

1.1. What is an OBD2 Code?

An OBD2 code is a standardized system of codes used to identify problems in a vehicle’s engine, transmission, and other systems. These codes are generated by the car’s computer when it detects a malfunction or reading outside of the normal parameters.

1.1.1. Standardization of Codes

The Society of Automotive Engineers (SAE) established the initial set of OBD2 codes. The Environmental Protection Agency (EPA) mandated that all cars sold in the United States after 1996 comply with OBD2 standards, as noted in EPA regulation 40 CFR Part 86. This standardization ensures that any OBD2 scanner can read codes from any vehicle, regardless of make or model.

1.1.2. Code Structure

OBD2 codes typically consist of five characters: one letter followed by four numbers.

• The letter indicates the system:
  • P: Powertrain (engine, transmission)
  • B: Body (airbags, central locking)
  • C: Chassis (ABS, suspension)
  • U: Network (communication systems)
• The first number indicates whether the code is generic (0) or manufacturer-specific (1, 2, or 3).
• The remaining three numbers specify the exact fault.

For example, a P0300 code indicates a generic powertrain issue related to random or multiple cylinder misfires.

1.2. Why are OBD2 Codes Important for Mercedes Owners?

OBD2 codes provide valuable information about your Mercedes-Benz’s health, enabling you to:

• Diagnose Problems Early: Identify issues before they escalate into costly repairs.
• Make Informed Decisions: Understand the severity of a problem and whether it requires immediate attention.
• Communicate Effectively with Mechanics: Provide specific information to your mechanic, potentially saving time and money on diagnosis.
• Monitor Vehicle Performance: Keep track of your car’s performance and identify potential issues over time.

1.3. Common Mercedes-Specific Codes

While many OBD2 codes are universal, some are specific to Mercedes-Benz vehicles. These codes often relate to the unique systems and technologies used in Mercedes-Benz cars, such as:

• Transmission Control Module (TCM) issues: Mercedes-Benz transmissions are known for their complexity, and specific codes may relate to shifting problems or electronic control issues.
• Sensotronic Brake Control (SBC) system failures: Some older Mercedes models have SBC systems, which can generate unique codes related to brake pressure and control.
• Body Control Module (BCM) problems: These codes can relate to issues with lighting, central locking, or other electronic accessories.
• Engine-specific codes: Mercedes-Benz engines may have codes related to specific sensors, fuel injection systems, or emission control components.

It’s helpful to consult a Mercedes-Benz specific repair manual or database to understand the meaning of these unique codes. You can also contact OBD2-SCANNER.EDU.VN for help.

Mercedes OBD2 port location

2. Essential Tools for Reading Mercedes OBD2 Codes

To read OBD2 codes from your Mercedes-Benz, you’ll need a compatible OBD2 scanner. These scanners range from basic, handheld units to more advanced, professional-grade tools.

2.1. Types of OBD2 Scanners

• Basic Handheld Scanners: These are the most affordable and user-friendly options. They typically display the OBD2 code and a brief description of the problem.
• Mid-Range Scanners: These scanners offer additional features such as the ability to view live data, perform basic tests, and reset the check engine light.
• Professional-Grade Scanners: These advanced tools are used by mechanics and offer comprehensive diagnostic capabilities, including advanced coding, programming, and access to manufacturer-specific data.
• Smartphone-Based Scanners: These scanners consist of a Bluetooth or Wi-Fi adapter that plugs into the OBD2 port and communicates with a smartphone app. They offer a range of features and are often more affordable than dedicated handheld scanners.

2.2. Features to Look For in an OBD2 Scanner

When choosing an OBD2 scanner for your Mercedes-Benz, consider the following features:

• Compatibility: Ensure the scanner is compatible with Mercedes-Benz vehicles and supports the necessary protocols.
• Code Definitions: The scanner should provide clear and accurate code definitions to help you understand the problem.
• Live Data: The ability to view live data from sensors and systems can be helpful for diagnosing intermittent problems.
• Reset Function: The scanner should allow you to reset the check engine light after repairing the problem.
• Ease of Use: Choose a scanner that is easy to navigate and has a user-friendly interface.
• Updates: Look for a scanner that can be updated with the latest code definitions and software.

2.3. Top OBD2 Scanner Recommendations for Mercedes

Here are some popular OBD2 scanners that are known to work well with Mercedes-Benz vehicles:

• Autel MaxiCOM MK808: A versatile mid-range scanner with good Mercedes-Benz coverage.
• iCarsoft MB II: A Mercedes-Benz specific scanner that offers advanced diagnostic capabilities.
• BlueDriver Bluetooth Professional OBDII Scan Tool: A smartphone-based scanner with a user-friendly app and access to a large database of code definitions.
• Launch Creader VII+: A reliable and affordable handheld scanner that supports all OBD2 protocols.

2.4. Using a Basic OBD2 Scanner

Here’s how to use a basic OBD2 scanner to read codes from your Mercedes-Benz:

1. Locate the OBD2 port, which is usually found under the dashboard on the driver’s side.
2. Plug the scanner into the OBD2 port.
3. Turn the ignition key to the “on” position, but do not start the engine.
4. The scanner will power on and may prompt you to enter vehicle information such as the year, make, and model.
5. Select the “Read Codes” or “Diagnostic Codes” option on the scanner’s menu.
6. The scanner will display any stored OBD2 codes.
7. Record the codes and their descriptions for further troubleshooting.

Dashboard with check engine light illuminated

3. Interpreting Mercedes OBD2 Codes

Once you’ve retrieved the OBD2 codes from your Mercedes-Benz, the next step is to interpret them. This involves understanding what the codes mean and identifying the potential causes of the problem.

3.1. Understanding Code Categories

As mentioned earlier, OBD2 codes are categorized by letter:

• P (Powertrain): These codes relate to the engine, transmission, fuel system, and emission control system.
• B (Body): These codes relate to the body, including airbags, central locking, power windows, and other accessories.
• C (Chassis): These codes relate to the chassis, including the anti-lock braking system (ABS), traction control system, and suspension system.
• U (Network): These codes relate to the vehicle’s communication network, including the Controller Area Network (CAN) bus.

3.2. Decoding Common Mercedes OBD2 Codes

Here’s a breakdown of some common Mercedes-Benz OBD2 codes and their potential causes:

Code	Description	Possible Causes
P0171	System Too Lean (Bank 1)	Vacuum leak, faulty oxygen sensor, dirty MAF sensor, fuel pressure issue
P0174	System Too Lean (Bank 2)	Vacuum leak, faulty oxygen sensor, dirty MAF sensor, fuel pressure issue
P0300	Random/Multiple Cylinder Misfire Detected	Faulty spark plugs, ignition coils, fuel injectors, vacuum leak, low compression
P0400	Exhaust Gas Recirculation Flow Malfunction	Faulty EGR valve, clogged EGR passages, vacuum leak
P0420	Catalyst System Efficiency Below Threshold (Bank 1)	Faulty catalytic converter, exhaust leak, faulty oxygen sensor
P0455	Evaporative Emission Control System Leak Detected (Gross Leak)	Loose or faulty gas cap, cracked or damaged EVAP hoses, faulty purge valve
P0715	Input/Turbine Speed Sensor Circuit Malfunction	Faulty input speed sensor, wiring issue, transmission problem
P0741	Torque Converter Clutch Circuit Performance or Stuck Off	Faulty torque converter clutch solenoid, transmission problem
C1000	BAS light, play in steering column causes steering angle sensor to lose memory(?)	Defective BAS module, faulty steering angle sensor, wiring issue
U0100	Lost Communication with ECM/PCM A	Wiring issue, faulty ECM/PCM
P261F71	The output for circulation pump has a malfunction. Actuator is blocked.	Coolant intrusion into vacuum system via the water pump.
P126A00	OM642 Engine oil cooler leak	Failure of component: intake manifolds, or the intake manifold actuator motor.

3.3. Using Online Resources and Repair Manuals

In addition to the information provided by the OBD2 scanner, you can use online resources and repair manuals to further understand the meaning of the codes.

• OBD2 Code Databases: Websites like OBD-Codes.com and AutoCodes.com offer extensive databases of OBD2 codes with detailed descriptions, possible causes, and troubleshooting tips.
• Mercedes-Benz Forums: Online forums dedicated to Mercedes-Benz vehicles can be a valuable resource for finding information and advice from other owners and mechanics.
• Repair Manuals: A Mercedes-Benz specific repair manual, such as those from Bentley Publishers or Haynes, can provide detailed information about the vehicle’s systems and components, as well as troubleshooting procedures.
• OBD2-SCANNER.EDU.VN: Contact us for any help you need.

3.4. The Importance of Confirming the Diagnosis

It’s important to remember that an OBD2 code is just a starting point for diagnosis. The code indicates a potential problem area, but it doesn’t necessarily pinpoint the exact cause.

Before replacing any parts or performing any repairs, it’s essential to confirm the diagnosis through further testing and inspection. This may involve:

• Visual Inspection: Check for obvious signs of damage, such as broken wires, cracked hoses, or leaks.
• Component Testing: Use a multimeter or other diagnostic tools to test the functionality of sensors, actuators, and other components.
• Live Data Analysis: Monitor live data from sensors and systems to identify abnormal readings or patterns.
• Technical Service Bulletins (TSBs): Check for any TSBs issued by Mercedes-Benz that may relate to the OBD2 code.

4. Basic Troubleshooting Steps for Mercedes OBD2 Codes

Once you’ve interpreted the OBD2 code and confirmed the diagnosis, you can begin troubleshooting the problem. Here are some basic troubleshooting steps you can take:

4.1. Addressing Simple Issues First

Before diving into complex repairs, it’s always a good idea to address simple issues first. These may include:

• Loose Gas Cap: A loose gas cap is a common cause of EVAP system codes (e.g., P0455).
• Low Fluid Levels: Check and top off any low fluid levels, such as engine oil, coolant, or transmission fluid.
• Loose Connections: Inspect wiring connectors and vacuum hoses for loose or damaged connections.
• Dirty Sensors: Clean dirty sensors, such as the MAF sensor or oxygen sensors.

4.2. Common DIY Repairs

Depending on the OBD2 code and your mechanical skills, you may be able to perform some DIY repairs. These may include:

• Replacing Spark Plugs or Ignition Coils: For misfire codes (e.g., P0300), replacing faulty spark plugs or ignition coils can often resolve the issue.
• Replacing Sensors: Replacing faulty sensors, such as oxygen sensors or MAF sensors, can often resolve codes related to system lean or rich conditions.
• Cleaning the Throttle Body: A dirty throttle body can cause idle problems and trigger OBD2 codes.
• Replacing Vacuum Hoses: Cracked or damaged vacuum hoses can cause vacuum leaks and trigger OBD2 codes.

4.3. When to Seek Professional Help

While some OBD2 code issues can be resolved with DIY repairs, others require professional help. It’s best to seek a qualified mechanic if:

• You’re not comfortable performing the repairs yourself.
• The problem is complex or requires specialized tools or knowledge.
• You’ve tried DIY repairs but the problem persists.
• The OBD2 code indicates a serious issue that could damage the vehicle if left unaddressed.

4.4. Finding a Reputable Mercedes-Benz Mechanic

When seeking professional help for your Mercedes-Benz, it’s important to choose a reputable mechanic who specializes in Mercedes-Benz vehicles. Look for a mechanic who:

• Has experience working on Mercedes-Benz vehicles.
• Uses high-quality parts and diagnostic equipment.
• Offers a warranty on their work.
• Has positive reviews from other customers.

You can also visit our facility in Los Angeles at 123 Main Street, Los Angeles, CA 90001, United States, contact us online or by phone/Whatsapp at +1 (641) 206-8880 to schedule a service appointment.

5. Preventing Future OBD2 Code Issues

While you can’t prevent all OBD2 code issues, you can take steps to minimize their occurrence and keep your Mercedes-Benz running smoothly.

5.1. Regular Maintenance

Regular maintenance is key to preventing OBD2 code issues. Follow the manufacturer’s recommended maintenance schedule, which includes:

• Oil changes
• Fluid checks and top-offs
• Filter replacements
• Spark plug replacements
• Tune-ups
• Inspections

5.2. Addressing Minor Issues Promptly

Don’t ignore minor issues, such as a rough idle or a strange noise. Addressing these issues promptly can prevent them from escalating into more serious problems that trigger OBD2 codes.

5.3. Using Quality Parts and Fluids

When performing maintenance or repairs, always use high-quality parts and fluids that meet Mercedes-Benz specifications. Using inferior parts or fluids can damage your vehicle and trigger OBD2 codes.

5.4. Driving Habits

Your driving habits can also affect the likelihood of OBD2 code issues. Avoid:

• Hard acceleration and braking
• Driving with low fuel levels
• Ignoring warning lights

5.5. Staying Informed

Stay informed about common Mercedes-Benz issues and maintenance procedures. This will help you identify potential problems early and take appropriate action.

A detailed view of a Mercedes-Benz engine bay

6. Specific Mercedes Fault Codes Explained

Delving into specific fault codes can provide a clearer understanding of what’s happening under the hood of your Mercedes. This section elaborates on some common Mercedes fault codes, their meanings, potential causes, and troubleshooting steps.

6.1. P0400 Series: Exhaust Gas Recirculation (EGR) Faults

The P0400 series of codes relates to the Exhaust Gas Recirculation (EGR) system, which is designed to reduce emissions by recirculating a portion of the exhaust gas back into the engine’s intake.

Mercedes Fault Code	Fault Code Meaning
P0466	Purge Flow Sensor Circuit Range/Performance
P0467	Purge Flow Sensor Circuit Low Input
P0468	Purge Flow Sensor Circuit High Input
P0469	Purge Flow Sensor Circuit Intermittent
P0470	Exhaust Pressure Sensor Malfunction
P0471	Exhaust Pressure Sensor Range/Performance
P0472	Exhaust Pressure Sensor Low
P0473	Exhaust Pressure Sensor High
P0474	Exhaust Pressure Sensor Intermittent
P0475	Exhaust Pressure Control Valve Malfunction
P0476	Exhaust Pressure Control Valve Range/Performance
P0477	Exhaust Pressure Control Valve Low
P0478	Exhaust Pressure Control Valve High
P0479	Exhaust Pressure Control Valve Intermittent
P0480	Cooling Fan 1 Control Circuit Malfunction
P0481	Cooling Fan 2 Control Circuit Malfunction
P0482	Cooling Fan 3 Control Circuit Malfunction
P0483	Cooling Fan Rationality Check Malfunction
P0484	Cooling Fan Circuit Over Current
P0485	Cooling Fan Power/Ground Circuit Malfunction

Common Causes:

• Faulty EGR valve
• Clogged EGR passages
• Vacuum leaks in the EGR system
• Faulty EGR pressure sensor

Troubleshooting Steps:

1. Inspect the EGR valve for carbon buildup or damage.
2. Clean the EGR passages to remove any clogs.
3. Check the vacuum hoses for leaks or cracks.
4. Test the EGR pressure sensor with a multimeter.
5. Replace the EGR valve if necessary.

6.2. P0500 Series: Vehicle Speed Sensor (VSS) Faults

The P0500 series of codes relates to the Vehicle Speed Sensor (VSS), which measures the speed of the vehicle and sends this information to the engine control unit (ECU) and other systems.

Mercedes Fault Code	Fault Code Meaning
P0500	Vehicle Speed Sensor Malfunction
P0501	Vehicle Speed Sensor Range/Performance
P0502	Vehicle Speed Sensor Low Input
P0503	Vehicle Speed Sensor Intermittent/Erratic/High
P0505	Idle Control System Malfunction
P0506	Idle Control System RPM Lower Than Expected
P0507	Idle Control System RPM Higher Than Expected
P0510	Closed Throttle Position Switch Malfunction
P0520	Engine Oil Pressure Sensor/Switch Circuit Malfunction
P0521	Engine Oil Pressure Sensor/Switch Circuit Range/Performance
P0522	Engine Oil Pressure Sensor/Switch Circuit Low Voltage
P0523	Engine Oil Pressure Sensor/Switch Circuit High Voltage
P0530	A/C Refrigerant Pressure Sensor Circuit Malfunction
P0531	A/C Refrigerant Pressure Sensor Circuit Range/Performance
P0532	A/C Refrigerant Pressure Sensor Circuit Low Input
P0533	A/C Refrigerant Pressure Sensor Circuit High Input
P0534	Air Conditioner Refrigerant Charge Loss
P0550	Power Steering Pressure Sensor Circuit Malfunction
P0551	Power Steering Pressure Sensor Circuit Range/Performance
P0552	Power Steering Pressure Sensor Circuit Low Input
P0553	Power Steering Pressure Sensor Circuit High Input
P0554	Power Steering Pressure Sensor Circuit Intermittent
P0560	System Voltage Malfunction
P0561	System Voltage Unstable
P0562	System Voltage Low
P0563	System Voltage High
P0565	Cruise Control On Signal Malfunction
P0566	Cruise Control Off Signal Malfunction
P0567	Cruise Control Resume Signal Malfunction
P0568	Cruise Control Set Signal Malfunction
P0569	Cruise Control Coast Signal Malfunction
P0570	Cruise Control Accel Signal Malfunction
P0571	Cruise Control/Brake Switch A Circuit Malfunction
P0572	Cruise Control/Brake Switch A Circuit Low
P0573	Cruise Control/Brake Switch A Circuit High
P0574	Cruise Control Related Malfunction
P0575	Cruise Control Related Malfunction
P0576	Cruise Control Related Malfunction
P0578	Cruise Control Related Malfunction
P0579	Cruise Control Related Malfunction
P0580	Cruise Control Related Malfunction

Common Causes:

• Faulty VSS
• Wiring issues, such as broken or shorted wires
• Faulty ABS module
• Transmission problems

Troubleshooting Steps:

1. Inspect the VSS for damage or corrosion.
2. Check the wiring and connectors for damage.
3. Test the VSS with a multimeter.
4. Check the ABS module for proper operation.
5. Replace the VSS if necessary.

6.3. P0600 Series: Internal Control Module Faults

The P0600 series of codes relates to internal control module faults, which indicate a problem with the vehicle’s computer systems.

Mercedes Fault Code	Fault Code Meaning
P0600	Serial Communication Link Malfunction
P0601	Internal Control Module Memory Check Sum Error
P0602	Control Module Programming Error
P0603	Internal Control Module Keep Alive Memory (KAM) Error
P0604	Internal Control Module Random Access Memory (RAM) Error
P0605	Internal Control Module Read Only Memory (ROM) Error
P0606	PCM Processor Fault
P0608	Control Module VSS Output “A” Malfunction
P0609	Control Module VSS Output “B” Malfunction
P0620	Generator Control Circuit Malfunction
P0621	Generator Lamp “L” Control Circuit Malfunction
P0622	Generator Field “F” Control Circuit Malfunction
P0650	Malfunction Indicator Lamp (MIL) Control Circuit Malfunction
P0654	Engine RPM Output Circuit Malfunction
P0655	Engine Hot Lamp Output Control Circuit Malfunction
P0656	Fuel Level Output Circuit Malfunction

Common Causes:

• Faulty ECU/PCM
• Wiring issues
• Software problems
• Voltage problems

Troubleshooting Steps:

1. Check the wiring and connectors for damage.
2. Check the system voltage.
3. Try reprogramming the ECU/PCM.
4. Replace the ECU/PCM if necessary.

6.4. P0700 Series: Transmission Control System Faults

The P0700 series of codes relates to the transmission control system, which controls the shifting and operation of the transmission.

Mercedes Fault Code	Fault Code Meaning
P0700	Transmission Control System Malfunction
P0701	Transmission Control System Range/Performance
P0702	Transmission Control System Electrical
P0703	Torque Converter/Brake Switch B Circuit Malfunction
P0704	Clutch Switch Input Circuit Malfunction
P0705	Transmission Range Sensor Circuit malfunction (PRNDL Input)
P0706	Transmission Range Sensor Circuit Range/Performance
P0707	Transmission Range Sensor Circuit Low Input
P0708	Transmission Range Sensor Circuit High Input
P0709	Transmission Range Sensor Circuit Intermittent
P0710	Transmission Fluid Temperature Sensor Circuit Malfunction
P0711	Transmission Fluid Temperature Sensor Circuit Range/Performance
P0712	Transmission Fluid Temperature Sensor Circuit Low Input
P0713	Transmission Fluid Temperature Sensor Circuit High Input
P0714	Transmission Fluid Temperature Sensor Circuit Intermittent
P0715	Input/Turbine Speed Sensor Circuit Malfunction
P0716	Input/Turbine Speed Sensor Circuit Range/Performance
P0717	Input/Turbine Speed Sensor Circuit No Signal
P0718	Input/Turbine Speed Sensor Circuit Intermittent
P0719	Torque Converter/Brake Switch B Circuit Low
P0720	Output Speed Sensor Circuit Malfunction
P0721	Output Speed Sensor Range/Performance
P0722	Output Speed Sensor No Signal
P0723	Output Speed Sensor Intermittent
P0724	Torque Converter/Brake Switch B Circuit High
P0725	Engine Speed input Circuit Malfunction
P0726	Engine Speed Input Circuit Range/Performance
P0727	Engine Speed Input Circuit No Signal
P0728	Engine Speed Input Circuit Intermittent
P0730	Incorrect Gear Ratio
P0731	Gear 1 Incorrect Ratio
P0732	Gear 2 Incorrect Ratio
P0733	Gear 3 Incorrect Ratio
P0734	Gear 4 Incorrect Ratio
P0735	Gear 5 Incorrect Ratio
P0736	Reverse Incorrect Gear Ratio
P0740	Torque Converter Clutch Circuit Malfuction
P0741	Torque Converter Clutch Circuit Performance or Stuck Off
P0742	Torque Converter Clutch Circuit Stuck On
P0743	Torque Converter Clutch Circuit Electrical
P0744	Torque Converter Clutch Circuit Intermittent
P0745	Pressure Control Solenoid Malfunction
P0746	Pressure Control Solenoid Performance or Stuck Off
P0747	Pressure Control Solenoid Stuck On
P0748	Pressure Control Solenoid Electrical
P0749	Pressure Control Solenoid Intermittent
P0750	Shift Solenoid A Malfunction
P0751	Shift Solenoid A Performance or Stuck Off
P0752	Shift Solenoid A Stuck On
P0753	Shift Solenoid A Electrical
P0754	Shift Solenoid A Intermittent
P0755	Shift Solenoid B Malfunction
P0756	Shift Solenoid B Performance or Stuck Off
P0757	Shift Solenoid B Stuck On
P0758	Shift Solenoid B Electrical
P0759	Shift Solenoid B Intermittent
P0760	Shift Solenoid C Malfunction
P0761	Shift Solenoid C Performance or Stuck Off
P0762	Shift Solenoid C Stuck On
P0763	Shift Solenoid C Electrical
P0764	Shift Solenoid C Intermittent
P0765	Shift Solenoid D Malfunction
P0766	Shift Solenoid D Performance or Stuck Off
P0767	Shift Solenoid D Stuck On
P0768	Shift Solenoid D Electrical
P0769	Shift Solenoid D Intermittent
P0770	Shift Solenoid E Malfunction
P0771	Shift Solenoid E Performance or Stuck Off
P0772	Shift Solenoid E Stuck On
P0773	Shift Solenoid E Electrical
P0774	Shift Solenoid E Intermittent
P0780	Shift Malfunction
P0781	1-2 Shift Malfunction
P0782	2-3 Shift Malfunction
P0783	3-4 Shift Malfunction
P0784	4-5 Shift Malfunction
P0785	Shift/Timing Solenoid Malfunction
P0786	Shift/Timing Solenoid Range/Performance
P0787	Shift/Timing Solenoid Low
P0788	Shift/Timing Solenoid High
P0789	Shift/Timing Solenoid Intermittent
P0790	Normal/Performance Switch Circuit Malfunction

Common Causes:

• Low transmission fluid level
• Faulty shift solenoids
• Faulty transmission speed sensors
• Transmission problems

Troubleshooting Steps:

1. Check the transmission fluid level.
2. Test the shift solenoids with a multimeter.
3. Check the transmission speed sensors.
4. Consult a transmission specialist.

6.5. P0800 Series: Transmission Related Faults

The P0800 series of codes is associated with transmission-related issues, particularly those involving control circuits and switches.

Mercedes Fault Code	Fault Code Meaning
P0801	Reverse Inhibit Control Circuit Malfunction
P0803	1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction
P0804	1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction
P0805	Clutch Position Sensor Circuit Malfunction
P0806	Clutch Position Sensor Circuit Range/Performance
P0807	Clutch Position Sensor Circuit Low
P0808	Clutch Position Sensor Circuit High
P0809	Clutch Position Sensor Circuit Intermittent Ckt
P0810	Clutch Position Control Malfunction
P0811	Clutch Slippage Excessive
P0812	Reverse Input Circuit Malfunction
P0813	Reverse Output Circuit Malfunction
P0814	Trans Range Display Circuit Malfunction
P0815	Upshift Switch Circuit Malfunction
P0816	Downshift Switch Circuit Malfunction
P0817	Starter Disable Circuit
P0818	Driveline Disconn. Switch Input
P0820	Gear Lever X-Y Sensor Circuit
P0821	Gear Lever X Sensor Circuit
P0822	Gear Lever Y Sensor Circuit
P0823	Gear Lever X Sensor Circuit Intermittent Ckt
P0824	Gear Lever Y Sensor Circuit Intermittent Ckt
P0830	Clutch Position Switch A Circuit Malfunction
P0831	Clutch Position Switch A Circuit Low
P0832	Clutch Position Switch A Circuit High
P0833	Clutch Position Switch B Circuit Malfunction
P0834	Clutch Position Switch B Circuit Low
P0835	Clutch Position Switch B Circuit High
P0836	4 Wheel Drive Switch Circuit Malfunction
P0837	4 Wheel Drive Switch CKT Range/Perf
P0838	4 Wheel Drive Switch Circuit Low
P0839	4 Wheel Drive Switch Circuit High
P0840	Trans Fluid Press Sensor/Switch A Circuit Malfunction
P0841	Trans Fluid Press Sensor/Switch A CKT Range/Perf
P0842	Trans Fluid Press Sensor/Switch A Circuit Low
P0843	Trans Fluid Press Sensor/Switch A Circuit High
P0844	Trans Fluid Press Sensor/Switch A CKT Intermittent
P0845	Trans Fluid Press Sensor/Switch B Circuit Malfunction
P0846	Trans Fluid Press Sensor/Switch B CKT Range/Perf
P0847	Trans Fluid Press Sensor/Switch B Circuit Low
P0848	Trans Fluid Press Sensor/Switch B Circuit High
P0849	Trans Fluid Press Sensor/Switch B CKT Intermittent

Common Causes:

• Faulty switches or sensors
• Wiring problems within the transmission control system
• Issues with the clutch position sensor
• Problems with the 4-wheel drive switch

Troubleshooting Steps:

1. Inspect all related switches and sensors for damage or corrosion.
2. Check the wiring for any signs of wear, damage, or loose connections.
3. Test the functionality of the switches and sensors using a multimeter.
4. Consult