How to Reset Exhaust Fluid Quality Poor: A Comprehensive Guide

Exhaust Fluid Quality Poor is a warning message that can appear on the dashboard of diesel vehicles equipped with a selective catalytic reduction (SCR) system. This system utilizes Diesel Exhaust Fluid (DEF) to reduce harmful emissions and ensure compliance with environmental regulations. When the exhaust fluid quality is compromised, it can negatively affect the performance and emissions of the vehicle. So it’s important to reset it.

The Importance of Maintaining Proper Exhaust Fluid Quality

Proper exhaust fluid quality is essential for the effective operation of the SCR system. DEF helps convert harmful nitrogen oxide (NOx) emissions into harmless nitrogen and water vapor through a chemical reaction. If the exhaust fluid quality is poor, the SCR system may not function optimally, leading to increased emissions and potential damage to the engine.

Common Causes of Exhaust Fluid Quality Poor

Several factors can contribute to exhaust fluid quality issues. By understanding these causes, you can take appropriate steps to address them and reset the exhaust fluid quality poor warning.

Low DEF (Diesel Exhaust Fluid) Level

One common cause of exhaust fluid quality poor is a low DEF level. DEF is a precise mixture of deionized water and urea, and when the level is insufficient, the concentration of urea may be too high, affecting the fluid’s quality. Regularly checking and maintaining the DEF level is crucial.

Contaminated or Impure DEF

Using contaminated or impure DEF can also lead to exhaust fluid quality problems. Contaminants such as dirt, dust, or other substances can introduce impurities into the DEF, affecting its composition and performance. It is essential to use high-quality DEF from reputable sources to avoid contamination.

DEF System Malfunction or Sensor Failure

Issues with the DEF system itself, such as malfunctioning components or sensor failures, can trigger the exhaust fluid quality poor warning. These malfunctions can disrupt the proper measurement and injection of DEF, resulting in poor fluid quality. In such cases, diagnosing and repairing the DEF system is necessary.

Extreme Temperatures and Environmental Factors

Extreme temperatures, both hot and cold, can impact the quality of DEF. Freezing temperatures can cause DEF to crystallize or expand, potentially leading to system blockages or damage. High temperatures can cause DEF to degrade, reducing its effectiveness. It is important to store DEF properly and protect it from extreme temperature conditions.

Step-by-Step Guide: How to Reset Exhaust Fluid Quality Poor

If you encounter the “Exhaust Fluid Quality Poor” warning, follow these steps to reset it and restore proper functioning of the SCR system.

Step 1: Identify the Warning Message

When the warning message appears on your dashboard, take note of the specific wording and any accompanying symbols. This information will help you diagnose the problem and find the appropriate solution.

Step 2: Check DEF Level and Quality

Inspect the DEF level in your vehicle’s dedicated DEF tank. Ensure that the level is above the minimum threshold indicated by the manufacturer. Additionally, visually examine the DEF for any signs of contamination or impurities.

Step 3: Refill or Replace DEF if Needed

If the DEF level is low or the fluid is contaminated, refill the DEF tank with a high-quality, manufacturer-approved DEF. If the DEF appears severely contaminated, it may be necessary to drain and replace it entirely.

Step 4: Clearing the Exhaust Fluid Quality Poor Message

There are two common methods to reset the exhaust fluid quality poor warning: using the vehicle’s onboard computer system or an OBD-II scanner.

4.1 Resetting the Message Using the Vehicle’s Onboard Computer System

Consult your vehicle’s user manual or manufacturer’s instructions to locate the menu or settings option for clearing warning messages. Access the appropriate menu, find the “Exhaust Fluid Quality Poor” warning, and select the option to reset or clear it. Follow the prompts on the screen to complete the process.

4.2 Resetting the Message with an OBD-II Scanner

If your vehicle supports OBD-II diagnostics, you can use an OBD-II scanner to reset the warning message. Connect the scanner to the OBD-II port, typically located beneath the dashboard. Follow the scanner’s instructions to access the vehicle’s computer system, locate the exhaust fluid quality poor warning, and reset it.

Frequently Asked Questions

Here are some commonly asked questions to clarify the resetting fluid quality –

Q: What does the “Exhaust Fluid Quality Poor” warning mean?

A: The “Exhaust Fluid Quality Poor” warning indicates an issue with the quality of the DEF in your vehicle’s SCR system. It requires attention to ensure optimal performance and emissions compliance.

Q: Can I continue driving with the “Exhaust Fluid Quality Poor” warning?

A: warning can lead to increased emissions, potential engine damage, and potential legal compliance issues.

Q: What are the consequences of ignoring the “Exhaust Fluid Quality Poor” warning?

A: Ignoring the “Exhaust Fluid Quality Poor” warning can have several consequences. Firstly, it can lead to increased emissions, potentially causing your vehicle to fail emission tests or violate environmental regulations. Secondly, it may result in reduced engine performance and fuel efficiency. Finally, ignoring the warning can potentially cause damage to the SCR system, resulting in costly repairs.

Q: What should I do if the “Exhaust Fluid Quality Poor” warning persists after resetting it?

A: If the warning message persists even after resetting it, there may be an underlying issue with the DEF system. In such cases, it is recommended to seek professional assistance from a qualified technician or contact your vehicle’s manufacturer for guidance. They can diagnose the problem and perform any necessary repairs to resolve the issue.

Q: How can I prevent exhaust fluid quality issues in the future?

A: To prevent exhaust fluid quality issues, it is crucial to follow these practices:

  • Regularly check the DEF level and maintain it above the minimum threshold.
  • Use high-quality DEF from reputable sources that meet the ISO 22241 standard.
  • Store DEF properly, away from extreme temperatures and contaminants.
  • Perform routine maintenance and inspections as per the manufacturer’s recommendations.
  • Address any warning messages or system malfunctions promptly to prevent further issues.


Remember, the “Exhaust Fluid Quality Poor” warning should never be ignored. Taking the necessary steps to reset the warning and address the underlying causes will not only keep your vehicle running smoothly but also contribute to a cleaner environment.

By following the guidelines outlined in this comprehensive guide on how to reset exhaust fluid quality poor, you can confidently reset the exhaust fluid quality poor warning and ensure that your vehicle’s SCR system operates optimally. Regular maintenance, attention to DEF levels and quality, and prompt action, when warning messages appear, will help you avoid potential complications and enjoy a more efficient and eco-friendly driving experience.

Stay informed, stay proactive, and take care of your vehicle’s exhaust fluid quality to enjoy a smoother and more environmentally responsible ride.

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