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 part of the car that helps reduce pollution has asked the car's computer to turn on the check engine light.
The Reductant Control Module monitors the system that reduces emissions and requests the Malfunction Indicator Lamp (MIL) to turn on if it detects a problem.
The P20C9 code is triggered when the Reductant Control Module detects an issue in the emission reduction system and requests the Engine Control Module (ECM) to illuminate the Malfunction Indicator Lamp (MIL). This is often related to the diesel exhaust fluid (DEF) system in diesel engines.
• Check engine light is on
• Possible reduction in engine performance
• Increased emissions
• Faulty Reductant Control Module
• Issues with the diesel exhaust fluid (DEF) system
• Wiring problems or poor electrical connections
MIL: Malfunction Indicator Lamp, also known as the check engine light.
DEF: Diesel Exhaust Fluid, a fluid used in diesel engines to reduce emissions.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections to the Reductant Control Module.
• Check the DEF system for leaks or blockages.
• Repair or replace faulty wiring or connectors.
• Replace the Reductant Control Module if necessary.
• Service the DEF system to ensure proper operation.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $800
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regularly maintain the DEF system.
• Ensure quality DEF fluid is used.
• Inspect wiring and connections periodically.
Emission System Issue
• Do not ignore the check engine light.
• Have the vehicle inspected by a professional.
• Keep up with regular maintenance.
Check with your vehicle manufacturer for warranty coverage related to emissions systems.
This code has become more common with the increased use of DEF systems in diesel engines to meet stricter emission standards.
Moderate – While the vehicle may still operate, emissions and performance could be affected.
Driving with a malfunctioning emission system can lead to increased pollution and may not comply with local emission laws.
• Engine running
• Vehicle warmed up
The Reductant Control Module is typically located near the DEF tank or in the engine compartment.
Q: Can I drive with a P20C9 code?
A: While you may be able to drive, it's best to address the issue to avoid increased emissions and potential engine performance problems.
Q: What happens if I ignore the P20C9 code?
A: Ignoring the code can lead to increased emissions, potential engine performance issues, and may result in failing an emissions test.
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