AdBlue Check Engine Light Mercedes: Diagnosis and Solutions

Are you experiencing an Adblue Check Engine Light Mercedes issue? CARDIAGTECH.NET is here to help you diagnose and resolve this common problem, ensuring your Mercedes-Benz runs smoothly and efficiently while adhering to emission standards. Find solutions for your car and discover the best tools and equipment for the job.

1. Understanding AdBlue and Your Mercedes-Benz

AdBlue, also known as Diesel Exhaust Fluid (DEF), is a vital component in modern diesel Mercedes-Benz vehicles. It plays a critical role in reducing nitrogen oxide (NOx) emissions, helping your car meet stringent environmental regulations. Let’s delve into what AdBlue is and its importance.

1.1. What is AdBlue?

AdBlue is a non-toxic, colorless solution comprised of urea and deionized water. It’s stored in a separate tank in your Mercedes-Benz and injected into the exhaust system.

1.2. How Does AdBlue Work?

In the Selective Catalytic Reduction (SCR) system, AdBlue reacts with NOx in the exhaust gas, converting it into harmless nitrogen and water. This process significantly lowers harmful emissions.

1.3. Why is AdBlue Important for Your Mercedes-Benz?

Environmental Compliance: AdBlue helps your Mercedes-Benz meet emission standards, avoiding potential fines and ensuring compliance with environmental regulations.
Optimal Performance: A properly functioning AdBlue system ensures your engine operates efficiently, maintaining optimal fuel economy and performance.
Preventing Damage: Neglecting AdBlue warnings can lead to engine damage and costly repairs.

2. Decoding the AdBlue Check Engine Light

When the AdBlue check engine light illuminates in your Mercedes-Benz, it signals a problem within the AdBlue system. Identifying the cause is crucial for effective troubleshooting.

2.1. Common Reasons for the AdBlue Check Engine Light

Low AdBlue Level: The most frequent cause. The system detects a low level in the AdBlue tank.
Faulty AdBlue Injector: A malfunctioning injector can disrupt the AdBlue injection process.
NOx Sensor Issues: Faulty NOx sensors can trigger the light due to incorrect readings.
AdBlue Pump Problems: A failing pump can prevent AdBlue from reaching the exhaust system.
Crystallization in the System: AdBlue can crystallize, causing blockages and triggering the warning light.
AdBlue Quality Issues: Using low-quality or contaminated AdBlue can damage the system and activate the light.

2.2. Understanding the Warning Messages

Mercedes-Benz vehicles display various messages related to AdBlue issues. Understanding these messages is key to diagnosing the problem.

Warning Message	Meaning
“Check AdBlue Level”	Indicates a low AdBlue level and requires refilling.
“AdBlue Malfunction”	Signals a more serious issue within the AdBlue system.
“Engine Start Not Possible”	Indicates a critical AdBlue system failure, preventing engine start to avoid excessive emissions.
“AdBlue Refill Required: X Miles”	Provides an estimated mileage until AdBlue runs out.

2.3 The Impact of Ignoring the Adblue Check Engine Light

Ignoring the AdBlue check engine light can lead to various issues affecting your vehicle’s performance and potentially causing long-term damage. Here’s a breakdown of the potential consequences:

Reduced Engine Performance: The engine control unit (ECU) may limit engine power and torque to reduce emissions, resulting in sluggish acceleration and overall reduced performance.
Engine Shutdown: In some cases, if the AdBlue system is severely malfunctioning or the AdBlue tank is empty, the ECU may prevent the engine from starting to avoid excessive emissions, leaving you stranded.
Damage to the SCR System: Running the vehicle without sufficient or properly functioning AdBlue can damage the selective catalytic reduction (SCR) system, leading to costly repairs.
Increased Emissions: The primary purpose of AdBlue is to reduce harmful nitrogen oxide (NOx) emissions. Ignoring the warning light means your vehicle will emit higher levels of pollutants, contributing to environmental damage and potentially failing emissions tests.
Fines and Penalties: In some regions, operating a vehicle with a malfunctioning emissions system can result in fines and penalties.
Voided Warranty: Neglecting the AdBlue system can void the warranty on related components, leaving you responsible for repair costs.

Source: U.S. Environmental Protection Agency (EPA)

3. Step-by-Step Guide to Diagnosing the AdBlue Check Engine Light

Diagnosing the AdBlue check engine light involves a systematic approach to pinpoint the root cause. Here’s a comprehensive guide:

3.1. Step 1: Check the AdBlue Level

Procedure: Use the vehicle’s display to check the AdBlue level. Consult your owner’s manual for the exact procedure.
Tools: None required for initial check.
Expected Outcome: If the level is low, refill the AdBlue tank.
CARDIAGTECH.NET Tip: Keep a spare container of AdBlue in your garage for convenient refills. Contact us at Whatsapp: +1 (641) 206-8880 for recommendations on high-quality AdBlue products.

3.2. Step 2: Inspect the AdBlue Tank and Cap

Procedure: Check for any visible damage or leaks around the AdBlue tank and cap. Ensure the cap is properly sealed.
Tools: Flashlight.
Expected Outcome: The tank and cap should be intact with no signs of leaks.
CARDIAGTECH.NET Tip: A damaged cap can lead to contamination of the AdBlue, triggering the warning light. Replace any damaged components immediately; CARDIAGTECH.NET can help you source these parts.

3.3. Step 3: Use an OBD-II Scanner

Procedure: Connect an OBD-II scanner to your Mercedes-Benz to read the diagnostic trouble codes (DTCs).
Tools: OBD-II scanner.
Expected Outcome: The scanner will display specific codes related to the AdBlue system.
CARDIAGTECH.NET Recommendation: Invest in a high-quality OBD-II scanner from CARDIAGTECH.NET to accurately diagnose AdBlue issues. Our top pick is the Autel MaxiSys MS906BT, known for its comprehensive diagnostic capabilities. Contact us at Whatsapp: +1 (641) 206-8880 for more information.

3.4. Step 4: Interpret the Diagnostic Trouble Codes (DTCs)

Common DTCs related to the AdBlue system include:

DTC	Description	Possible Cause
P20E8	Reductant Supply Pressure Too Low	Faulty AdBlue pump, blocked lines, or low AdBlue level.
P20EE	SCR NOx Catalyst Efficiency Below Threshold	Faulty NOx sensor, malfunctioning SCR catalyst, or AdBlue injection issues.
P204F	Reductant System Performance	AdBlue quality issues, injector problems, or SCR catalyst failure.
P20E9	Reductant Supply Pressure Too High	Faulty pressure regulator or AdBlue pump.
P13DF00	The reductant metering valve has a short circuit to ground.	Faulty metering valve, wiring issue, or ECU problem.

Source: National Institute for Automotive Service Excellence (ASE)

3.5. Step 5: Inspect the AdBlue Injector

Procedure: Check the AdBlue injector for clogs or damage.
Tools: Socket set, multimeter.
Expected Outcome: The injector should be clean and free from obstructions.
CARDIAGTECH.NET Tip: Use a multimeter to test the injector’s electrical continuity. If the injector is faulty, CARDIAGTECH.NET offers high-quality replacement injectors. Contact us at Whatsapp: +1 (641) 206-8880 for assistance.

3.6. Step 6: Check the NOx Sensors

Procedure: Inspect the NOx sensors for damage and test their functionality using a multimeter.
Tools: Multimeter, socket set.
Expected Outcome: The sensors should provide accurate readings.
CARDIAGTECH.NET Recommendation: Replace faulty NOx sensors with reliable replacements from CARDIAGTECH.NET. Our selection ensures accurate emission readings and optimal performance.

3.7. Step 7: Examine the AdBlue Pump

Procedure: Check the AdBlue pump for proper operation. Listen for unusual noises and test the pump’s electrical connections.
Tools: Multimeter, socket set.
Expected Outcome: The pump should operate smoothly and maintain consistent pressure.
CARDIAGTECH.NET Tip: A failing AdBlue pump can lead to significant performance issues. CARDIAGTECH.NET offers robust replacement pumps to keep your system running smoothly.

3.8. Step 8: Inspect for Crystallization

Procedure: Check the AdBlue lines, injector, and tank for any signs of crystallization.
Tools: Inspection mirror, cleaning solution.
Expected Outcome: The system should be free from AdBlue crystals.
CARDIAGTECH.NET Recommendation: Use a specialized cleaning solution to remove AdBlue crystals. CARDIAGTECH.NET provides effective cleaning products to maintain your AdBlue system.

4. Step-by-Step Guide to Fixing the AdBlue Check Engine Light

Once you’ve diagnosed the issue, follow these steps to fix the AdBlue check engine light:

4.1. Step 1: Refill the AdBlue Tank

Procedure: Purchase high-quality AdBlue and carefully refill the tank to the recommended level.
Tools: AdBlue fluid, funnel.
Expected Outcome: The AdBlue level should be within the recommended range.
CARDIAGTECH.NET Tip: Use a funnel to avoid spills and ensure proper filling. CARDIAGTECH.NET offers high-quality AdBlue fluids that meet Mercedes-Benz specifications.

4.2. Step 2: Replace the AdBlue Injector

Procedure: Disconnect the faulty injector and replace it with a new one.
Tools: Socket set, wrench.
Expected Outcome: The new injector should function correctly, restoring proper AdBlue injection.
CARDIAGTECH.NET Recommendation: Purchase a reliable replacement injector from CARDIAGTECH.NET. Our injectors are tested for performance and durability.

4.3. Step 3: Replace the NOx Sensors

Procedure: Remove the faulty NOx sensors and install new ones.
Tools: Socket set, wrench.
Expected Outcome: The new sensors should provide accurate emission readings, resolving the warning light.
CARDIAGTECH.NET Tip: Ensure the sensors are properly calibrated after installation. CARDIAGTECH.NET provides calibrated sensors for accurate performance.

4.4. Step 4: Replace the AdBlue Pump

Procedure: Disconnect the faulty pump and replace it with a new one.
Tools: Socket set, wrench.
Expected Outcome: The new pump should operate smoothly, ensuring consistent AdBlue supply.
CARDIAGTECH.NET Recommendation: CARDIAGTECH.NET offers high-quality replacement AdBlue pumps designed for Mercedes-Benz vehicles.

4.5. Step 5: Clean the AdBlue System

Procedure: Use a specialized cleaning solution to remove any AdBlue crystals from the system.
Tools: Cleaning solution, compressed air.
Expected Outcome: The system should be free from obstructions, allowing for proper AdBlue flow.
CARDIAGTECH.NET Tip: Use compressed air to ensure all lines are clear after cleaning. CARDIAGTECH.NET provides effective cleaning solutions for AdBlue systems.

4.6. Step 6: Reset the Check Engine Light

Procedure: Use an OBD-II scanner to reset the check engine light after completing the repairs.
Tools: OBD-II scanner.
Expected Outcome: The check engine light should turn off, indicating the issue has been resolved.
CARDIAGTECH.NET Recommendation: Use the Autel MaxiSys MS906BT to ensure accurate resetting and system diagnostics. Contact us at Whatsapp: +1 (641) 206-8880 for more information.

5. AdBlue System Maintenance Tips for Mercedes-Benz

Maintaining the AdBlue system in your Mercedes-Benz is crucial for preventing issues and ensuring optimal performance. Here are some essential maintenance tips:

5.1 Use High-Quality AdBlue

Why: High-quality AdBlue ensures the proper chemical composition and purity needed for efficient NOx reduction and prevents contamination that can damage the system.
How: Always purchase AdBlue from reputable suppliers that meet ISO 22241 standards. This standard ensures the AdBlue has the correct urea concentration and is free from impurities.
CARDIAGTECH.NET Tip: Source your AdBlue from CARDIAGTECH.NET to ensure you are using a product that meets Mercedes-Benz specifications. Contact us at Whatsapp: +1 (641) 206-8880 for recommendations.

5.2 Regular Inspections

Why: Regular inspections can catch minor issues before they escalate into major problems, saving you time and money on costly repairs.
How: Periodically check the AdBlue tank, lines, and injector for any signs of leaks, damage, or crystallization. Use a flashlight to inspect hard-to-reach areas.
CARDIAGTECH.NET Tip: Schedule routine inspections as part of your regular vehicle maintenance. CARDIAGTECH.NET can provide you with the necessary tools and guidance for these inspections.

5.3 Avoid Overfilling the AdBlue Tank

Why: Overfilling the AdBlue tank can cause the fluid to spill and potentially damage surrounding components. It can also lead to crystallization and system malfunctions.
How: Fill the tank to the recommended level, as indicated in your vehicle’s manual. Avoid topping off the tank unnecessarily.
CARDIAGTECH.NET Tip: Use a funnel to avoid spills and ensure you are filling the tank to the correct level. CARDIAGTECH.NET offers funnels and filling aids to make this process easier.

5.4 Proper Storage of AdBlue

Why: Proper storage of AdBlue is essential to maintain its quality and prevent contamination. Contaminated AdBlue can damage the SCR system and trigger warning lights.
How: Store AdBlue in a cool, dry place away from direct sunlight and extreme temperatures. Ensure the container is tightly sealed to prevent moisture and contaminants from entering.
CARDIAGTECH.NET Tip: Purchase AdBlue in containers that are specifically designed for its storage. CARDIAGTECH.NET can recommend suitable storage solutions to keep your AdBlue in optimal condition.

5.5 Prevent Crystallization

Why: AdBlue can crystallize over time, especially in areas with high temperatures or when the vehicle is not used frequently. Crystallization can block the injector and lines, leading to system malfunctions.
How: If you live in a hot climate or do not use your vehicle regularly, consider using an AdBlue additive that prevents crystallization. Regularly inspect the system for any signs of crystal buildup.
CARDIAGTECH.NET Tip: CARDIAGTECH.NET offers AdBlue additives that help prevent crystallization and keep your system clean. Contact us at Whatsapp: +1 (641) 206-8880 for more information.

5.6 Regular System Cleaning

Why: Regular cleaning of the AdBlue system helps remove any buildup of contaminants and ensures that all components are functioning correctly.
How: Periodically use a specialized cleaning solution to flush the AdBlue lines and injector. Follow the manufacturer’s instructions for the cleaning solution.
CARDIAGTECH.NET Tip: CARDIAGTECH.NET provides effective cleaning solutions specifically designed for AdBlue systems. These solutions help remove deposits and prevent future issues.

5.7 Check and Replace Filters

Why: Many AdBlue systems have filters that prevent contaminants from entering the injector and other critical components. Over time, these filters can become clogged and reduce the system’s efficiency.
How: Check the filters regularly and replace them as needed, following the manufacturer’s recommendations.
CARDIAGTECH.NET Tip: CARDIAGTECH.NET offers high-quality replacement filters for Mercedes-Benz AdBlue systems. Replacing these filters can help maintain optimal performance and prevent costly repairs.

5.8 Professional Servicing

Why: Regular professional servicing ensures that all aspects of the AdBlue system are functioning correctly. Certified technicians have the expertise and tools to diagnose and repair any issues.
How: Schedule regular servicing appointments with a trusted mechanic who is familiar with Mercedes-Benz AdBlue systems.
CARDIAGTECH.NET Tip: While CARDIAGTECH.NET provides the tools and parts you need, we also recommend seeking professional servicing for complex issues. Contact us at Whatsapp: +1 (641) 206-8880 for referrals to trusted service providers.

5.9 Monitor AdBlue Consumption

Why: Monitoring AdBlue consumption can provide valuable insights into the health of your system. A sudden increase in consumption may indicate a leak or other issue.
How: Keep track of how often you need to refill the AdBlue tank. Compare your consumption rate to the manufacturer’s specifications.
CARDIAGTECH.NET Tip: If you notice a significant change in AdBlue consumption, inspect the system for leaks and other potential problems. CARDIAGTECH.NET can help you diagnose and repair any issues you find.

5.10 Update Vehicle Software

Why: Vehicle software updates can improve the performance and efficiency of the AdBlue system. Manufacturers often release updates to address known issues and optimize system operation.
How: Check for software updates regularly and install them as recommended by Mercedes-Benz.
CARDIAGTECH.NET Tip: Use the Autel MaxiSys MS906BT to easily check for and install software updates on your Mercedes-Benz. Contact us at Whatsapp: +1 (641) 206-8880 for more information.

Source: Mercedes-Benz Official Website

6. Choosing the Right Tools from CARDIAGTECH.NET

Having the right tools is essential for diagnosing and fixing AdBlue system issues. CARDIAGTECH.NET offers a wide range of high-quality tools tailored for Mercedes-Benz vehicles.

6.1. OBD-II Scanners

Recommendation: The Autel MaxiSys MS906BT is a top choice for its comprehensive diagnostic capabilities and user-friendly interface.
Benefits: Accurate DTC readings, system resets, and live data monitoring.

6.2. Multimeters

Recommendation: The Fluke 115 is a reliable and accurate multimeter for testing electrical components in the AdBlue system.
Benefits: Precise voltage, current, and resistance measurements for accurate diagnostics.

6.3. Socket Sets and Wrenches

Recommendation: A high-quality socket set from GEARWRENCH provides the necessary tools for removing and installing AdBlue system components.
Benefits: Durable construction and a wide range of sizes for versatile use.

6.4. Inspection Mirrors

Recommendation: An extendable inspection mirror helps you see hard-to-reach areas of the AdBlue system for thorough inspections.
Benefits: Enhanced visibility for detecting leaks, damage, and crystallization.

6.5. Cleaning Solutions

Recommendation: A specialized AdBlue system cleaning solution effectively removes crystal buildup and ensures proper system function.
Benefits: Prevents blockages and maintains optimal AdBlue flow.

Contact CARDIAGTECH.NET at Whatsapp: +1 (641) 206-8880 to get personalized recommendations and assistance in choosing the right tools for your needs.

7. The Benefits of Professional Servicing

While many AdBlue system issues can be resolved with DIY methods, professional servicing offers several advantages:

Expert Diagnostics: Certified technicians have the expertise and advanced tools to accurately diagnose complex AdBlue system problems.
Proper Repairs: Professional servicing ensures that repairs are performed correctly, preventing future issues and maintaining system integrity.
Warranty Protection: Using certified technicians can protect your vehicle’s warranty and ensure that repairs meet manufacturer standards.

8. Real-World Scenarios and Solutions

Let’s examine some real-world scenarios and how to address them:

Scenario 1: Low AdBlue Level Warning

Problem: The “Check AdBlue Level” warning appears on the dashboard.
Solution: Refill the AdBlue tank with high-quality fluid. Ensure the cap is properly sealed.
Tools: AdBlue fluid, funnel.

Scenario 2: AdBlue Injector Clog

Problem: The engine runs rough, and the OBD-II scanner displays a code related to the AdBlue injector.
Solution: Remove and inspect the injector for clogs. Clean or replace the injector as needed.
Tools: Socket set, multimeter, cleaning solution.

Scenario 3: Faulty NOx Sensor

Problem: The check engine light is on, and the OBD-II scanner indicates a faulty NOx sensor.
Solution: Replace the faulty NOx sensor with a reliable replacement.
Tools: Socket set, multimeter.

Scenario 4: AdBlue Pump Failure

Problem: The engine lacks power, and the OBD-II scanner displays a code related to the AdBlue pump.
Solution: Replace the faulty AdBlue pump with a new one.
Tools: Socket set, multimeter.

Scenario 5: Crystallization in the AdBlue System

Problem: The vehicle displays an AdBlue malfunction warning, and there are visible crystal deposits around the injector and lines.
Solution: Clean the AdBlue system using a specialized cleaning solution to remove crystal buildup. Inspect and clean the injector and lines thoroughly.
Tools: Cleaning solution, socket set, inspection mirror, compressed air.

9. Understanding Mercedes-Benz AdBlue System Warranty

The warranty coverage for the AdBlue system in a Mercedes-Benz can vary based on several factors, including the age and mileage of the vehicle, the type of warranty (new car, extended, or certified pre-owned), and the specific components of the system. Here’s a detailed breakdown:

9.1. New Car Warranty

Coverage Period: Typically covers defects in materials or workmanship for a set period (e.g., 4 years or 50,000 miles, whichever comes first).
What’s Covered: Under the new car warranty, most components of the AdBlue system are covered, including the AdBlue tank, pump, injector, NOx sensors, and associated control modules.
What’s Not Covered: Normal wear and tear, damage from improper maintenance, or use of non-approved fluids may not be covered.

9.2. Extended Warranty

Coverage Period: Extends the coverage beyond the original new car warranty, offering protection for additional years or miles.
What’s Covered: The extent of coverage depends on the specific extended warranty plan. Comprehensive plans often cover the same components as the new car warranty, while more basic plans may have limited coverage.
What’s Not Covered: Review the terms and conditions of the extended warranty to understand exclusions, such as certain wear items or damage caused by neglect.

9.3. Certified Pre-Owned (CPO) Warranty

Coverage Period: Provides warranty coverage for certified pre-owned vehicles, often extending the original warranty or offering a new warranty period.
What’s Covered: CPO warranties typically cover major components, including the AdBlue system. The exact coverage will depend on the terms of the CPO program.
What’s Not Covered: As with other warranties, normal wear and tear, improper maintenance, or use of non-approved fluids may not be covered.

9.4. Specific AdBlue System Components

AdBlue Tank and Pump: Generally covered under warranty for defects in materials or workmanship.
AdBlue Injector: Usually covered, but issues caused by contaminated AdBlue may not be.
NOx Sensors: Covered for failures but not for issues resulting from improper maintenance or external factors.
Control Modules: Covered for defects but not for issues caused by unauthorized modifications or software tampering.

9.5. Factors Affecting Warranty Coverage

Maintenance Records: Maintaining detailed and up-to-date maintenance records is crucial. Mercedes-Benz may deny warranty claims if there is a lack of evidence of proper maintenance.
Approved Fluids: Using AdBlue that meets Mercedes-Benz specifications (ISO 22241) is essential. Using non-approved fluids can void warranty coverage for related components.
Modifications: Unauthorized modifications to the AdBlue system or other vehicle components can void the warranty.

Source: Mercedes-Benz USA Warranty Information

10. Why Choose CARDIAGTECH.NET for Your AdBlue System Needs?

CARDIAGTECH.NET is your trusted partner for all your Mercedes-Benz AdBlue system needs. Here’s why:

Expertise: We specialize in providing high-quality tools and equipment for diagnosing and repairing AdBlue systems.
Wide Selection: We offer a comprehensive range of OBD-II scanners, multimeters, socket sets, and cleaning solutions tailored for Mercedes-Benz vehicles.
Quality Assurance: Our products are sourced from trusted manufacturers and tested for performance and durability.
Customer Support: Our team of experts is available to provide personalized recommendations and technical support.

Don’t let the AdBlue check engine light keep you off the road. Contact CARDIAGTECH.NET today at 276 Reock St, City of Orange, NJ 07050, United States, or Whatsapp: +1 (641) 206-8880. Visit our website at CARDIAGTECH.NET to explore our wide range of products and services. Let us help you keep your Mercedes-Benz running smoothly and efficiently.

Frequently Asked Questions (FAQ)

What is AdBlue, and why is it important?
AdBlue, also known as Diesel Exhaust Fluid (DEF), is a non-toxic solution used in diesel vehicles to reduce nitrogen oxide (NOx) emissions. It helps vehicles meet environmental regulations and maintain optimal performance.
What causes the AdBlue check engine light to come on in my Mercedes-Benz?
The AdBlue check engine light can be triggered by several issues, including low AdBlue levels, a faulty AdBlue injector, NOx sensor problems, AdBlue pump failures, crystallization in the system, or poor AdBlue quality.
How do I check the AdBlue level in my Mercedes-Benz?
Most Mercedes-Benz models display the AdBlue level through the instrument cluster. Consult your owner’s manual for specific instructions on accessing this information.
Can I drive my Mercedes-Benz with the AdBlue check engine light on?
It’s not recommended. Ignoring the AdBlue warning can lead to reduced engine performance, potential engine shutdown, and damage to the SCR system.
What tools do I need to diagnose AdBlue system issues?
Essential tools include an OBD-II scanner, multimeter, socket set, wrench, and inspection mirror.
How often should I refill the AdBlue tank in my Mercedes-Benz?
The frequency of refills depends on driving conditions and vehicle usage. Typically, the AdBlue tank needs to be refilled every few thousand miles. Monitor the AdBlue level regularly.
Can I use any type of AdBlue in my Mercedes-Benz?
No, it’s crucial to use AdBlue that meets ISO 22241 standards to ensure proper chemical composition and purity.
What are the signs of AdBlue crystallization in the system?
Signs include visible crystal deposits around the injector and lines, as well as AdBlue system malfunction warnings on the dashboard.
How do I prevent AdBlue crystallization?
Use high-quality AdBlue, store it properly, and consider using an AdBlue additive to prevent crystallization. Regularly inspect and clean the system.
When should I seek professional servicing for my AdBlue system?
Seek professional servicing if you’re unable to diagnose or resolve the issue yourself, or if you suspect a complex problem. Certified technicians have the expertise and tools to accurately diagnose and repair AdBlue system issues.