Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the system that helps reduce pollution in your car is not working properly because it isn't getting enough of a special fluid it needs.
The code indicates that the reductant injection system, which is responsible for injecting a fluid to reduce emissions, is not receiving enough of this fluid, causing it to reach its control limits.
The P249D code is triggered when the engine control module (ECM) detects that the reductant injection system's flow rate is lower than expected. This system is part of the Selective Catalytic Reduction (SCR) system, which uses a urea-based fluid (commonly known as DEF, Diesel Exhaust Fluid) to reduce NOx emissions in diesel engines. A low flow condition may result from blockages, leaks, or a failing pump.
• Check Engine Light is on
• Reduced engine performance
• Increased emissions
• Clogged reductant injector
• Faulty reductant pump
• Leaking reductant lines
Reductant: A substance used to reduce emissions in a vehicle's exhaust system.
SCR: Selective Catalytic Reduction, a system used to reduce NOx emissions in diesel engines.
• Check for any stored trouble codes related to the SCR system.
• Inspect the reductant injector and lines for blockages or leaks.
• Test the reductant pump for proper operation.
• Clean or replace the reductant injector.
• Repair or replace any leaking lines.
• Replace the reductant pump if faulty.
• OBD-II scanner
• Pressure gauge
• Wrench set
$200 - $600
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regularly check and refill DEF fluid.
• Perform routine maintenance on the SCR system.
• Inspect reductant lines and injectors for leaks or blockages.
Emission Control Issue
• Do not ignore the Check Engine Light.
• Schedule a service appointment if you notice reduced performance.
• Regularly maintain your vehicle’s emission system.
Check with your vehicle manufacturer as emissions-related components may have extended warranties.
This code has become more common with the increased use of SCR systems in diesel vehicles to meet stricter emission standards.
Moderate – While the vehicle may still run, emissions are higher than normal, and performance may be affected.
Driving with this code may result in failing emissions tests and is harmful to the environment.
• Engine at operating temperature
• Vehicle in closed loop operation
The reductant injection system components are typically located near the exhaust system, including the DEF tank and associated lines.
Q: Can I drive with a P249D code?
A: You can drive, but it's not recommended as it can lead to increased emissions and potential engine performance issues.
Q: What happens if I ignore the P249D code?
A: Ignoring the code can lead to higher emissions, potential engine performance issues, and failing emissions tests.
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