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Engine-Codes – Generic – P249D

P249D Code - Closed Loop Reductant Injection Control At Limit – Flow Too Low

Quick Answer

The diagnostic trouble code P249D indicates an issue with the closed-loop reductant injection control system in the vehicle. Common causes include Malfunctioning Reductant Injector: A faulty reductant injector can lead to insufficient reductant flow, triggering the P249D code, Clogged Reductant Injector Nozzle: If the reductant injector nozzle is clogged or restricted, it can impede the flow of reductant, Faulty Reductant Pump: A malfunctioning reductant pump may not be able to supply an adequate amount of reductant to the injection system. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P249D indicates Closed Loop Reductant Injection Control At Limit – Flow Too Low.
Common causes
Common causes include Malfunctioning Reductant Injector: A faulty reductant injector can lead to insufficient reductant flow, triggering the P249D code, Clogged Reductant Injector Nozzle: If the reductant injector nozzle is clogged or restricted, it can impede the flow of reductant, Faulty Reductant Pump: A malfunctioning reductant pump may not be able to supply an adequate amount of reductant to the injection system.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 09, 2024
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Code P249D Description

The diagnostic trouble code P249D indicates an issue with the closed-loop reductant injection control system in the vehicle. This system is responsible for injecting a reductant, typically a urea-based solution known as diesel exhaust fluid (DEF), into the exhaust stream to reduce harmful emissions. When the flow of reductant is too low, it can lead to increased emissions and potentially cause the vehicle to fail emissions tests.

OBDII Code P249D - Closed Loop Reductant Injection Control At Limit – Flow Too Low
P249D Code - Closed Loop Reductant Injection Control At Limit – Flow Too Low

Common Causes of P249D

  1. Malfunctioning Reductant Injector: A faulty reductant injector can lead to insufficient reductant flow, triggering the P249D code.
  2. Clogged Reductant Injector Nozzle: If the reductant injector nozzle is clogged or restricted, it can impede the flow of reductant.
  3. Faulty Reductant Pump: A malfunctioning reductant pump may not be able to supply an adequate amount of reductant to the injection system.
  4. Issues with Reductant Tank or Supply Lines: Problems with the reductant tank or supply lines, such as leaks or blockages, can affect the flow of reductant.

Symptoms of P249D

  1. Check Engine Light: The most common symptom associated with the P249D code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced Fuel Efficiency: A decrease in fuel efficiency may be observed due to the inefficient operation of the reductant injection system.
  3. Increased Emissions: The vehicle may produce higher emissions than usual, leading to potential environmental concerns.
  4. Failed Emissions Test: If the issue is not resolved, the vehicle may fail emissions testing due to elevated emissions output.

How to Fix P249D

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble codes and perform a thorough inspection of the reductant injection system to pinpoint the exact cause of the low flow issue.
  2. Inspect Reductant Components: Check the reductant injector, nozzle, pump, tank, and supply lines for any signs of damage, clogs, or leaks.
  3. Clean or Replace Components: Clean or replace the affected components, such as the reductant injector nozzle or pump, as necessary to restore proper reductant flow.
  4. Reset the Fault Codes: Clear the fault codes from the vehicle's computer using the diagnostic scanner after completing the repair to reset the system.
  5. Test Drive and Monitor: Take the vehicle for a test drive to ensure that the reductant injection system is functioning correctly and monitor for any recurrence of the P249D code.

Cost to Fix P249D

The cost of repairing the P249D code can vary depending on the specific cause of the issue and the necessary repairs. On average, repairing the closed-loop reductant injection control system can range from $200 to $800, including parts and labor. However, it's important to note that the actual repair costs may differ based on factors such as the vehicle make and model, the extent of the repairs needed, and the labor rates at the auto repair shop. It's recommended to obtain a detailed estimate from a trusted mechanic to determine the precise cost for addressing this issue.

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Code P249D Information for Specific Makes

  • P249D Chevrolet — Closed Loop Reductant Injection Control At Limit – Flow Too Low
  • P249D Ford — Closed Loop Reductant Injection Control At Limit - Flow Too Low
  • P249D GMC — Closed Loop Reductant Injection Control At Limit – Flow Too Low
  • P249D Mercedes-Benz — Closed Loop Reductant Injection Control At Limit - Flow Too Low
About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P249D Code

1. What are common symptoms of OBDII code P249D?

The common symptoms of OBDII code P249D include the check engine light being illuminated on the dashboard, reduced engine performance, and potential issues with the exhaust system.

2. What can cause OBDII code P249D to trigger?

The triggering of OBDII code P249D is often caused by issues such as a faulty reductant injector, clogged reductant lines, low-quality diesel exhaust fluid (DEF), or a malfunctioning reductant control module.

3. How serious is OBDII code P249D?

OBDII code P249D should be addressed promptly as it relates to the reductant injection system, which is crucial for reducing harmful emissions. Ignoring this code can lead to increased emissions, reduced fuel efficiency, and potential damage to the vehicle's engine components.

4. Can I continue driving with OBDII code P249D present?

It is not recommended to continue driving with OBDII code P249D present, as this can lead to further damage to the vehicle's emission control system. It is best to have the issue diagnosed and repaired as soon as possible.

5. How can I diagnose OBDII code P249D?

Diagnosing OBDII code P249D typically involves using a scan tool to retrieve the code, inspecting the reductant injection system components for any visible damage or leaks, and testing the functionality of the reductant injector and related components.

6. What are some repair tips for OBDII code P249D?

Repair tips for OBDII code P249D may include replacing a faulty reductant injector, clearing any clogs in the reductant lines, ensuring the DEF is of high quality, and checking the reductant control module for proper operation.

7. Can I reset OBDII code P249D without fixing the underlying issue?

While you can clear the code temporarily by resetting the vehicle's computer, it is not recommended to do so without addressing the underlying issue. The code is likely to reappear if the root cause is not resolved.

8. How much does it cost to repair OBDII code P249D?

The cost of repairing OBDII code P249D can vary depending on the specific cause of the issue, the extent of the damage, and the labor rates in your area. It is advisable to consult with a professional mechanic for an accurate estimate.

9. Will OBDII code P249D cause my vehicle to fail emissions testing?

Yes, OBDII code P249D is related to the vehicle's emissions control system, and if left unresolved, it can cause your vehicle to fail emissions testing due to increased emissions levels.

10. How can I prevent OBDII code P249D from reoccurring?

To prevent OBDII code P249D from reoccurring, it is essential to use high-quality diesel exhaust fluid, maintain regular servicing of the reductant injection system, and address any related issues promptly to ensure proper functioning of the emission control system.

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