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 a part of the car's system that helps reduce pollution is not turning off when it should.
The P20EB code indicates an issue with the timing of the power relay for the reductant control module, which is responsible for managing the diesel exhaust fluid system in diesel engines.
The reductant control module manages the diesel exhaust fluid (DEF) system, which helps reduce emissions in diesel engines. The power relay for this module should de-energize (turn off) at specific times. If it turns off too late, the system may not function properly, leading to increased emissions.
• Check Engine Light is on
• Increased emissions
• Possible decrease in fuel efficiency
• Faulty reductant control module power relay
• Wiring issues or poor connections
• Defective reductant control module
Reductant: A substance used to reduce emissions, such as diesel exhaust fluid.
Relay: An electrical switch that opens and closes under the control of another electrical circuit.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors related to the reductant control module.
• Test the power relay for proper operation.
• Replace the faulty power relay.
• Repair or replace damaged wiring or connectors.
• Replace the reductant control module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $500
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regular maintenance of the DEF system
• Routine checks of wiring and connections
• Timely replacement of faulty components
Emission Control System Issue
• Address the issue promptly to avoid increased emissions.
• Consult a professional mechanic if unsure about the repairs.
Check with the vehicle manufacturer for warranty coverage on emission-related components.
This code is relatively common in diesel vehicles equipped with DEF systems, especially as they age.
Moderate – While the vehicle may still operate, emissions may be higher than acceptable standards.
Driving with this code may lead to failing emissions tests and could be illegal in areas with strict emission regulations.
• Engine at operating temperature
• Vehicle in normal operating conditions
The reductant control module is typically located near the DEF tank or in the engine compartment.
Q: Can I drive with the P20EB code?
A: Yes, but it's recommended to fix it soon to avoid increased emissions and potential legal issues.
Q: What is a reductant control module?
A: It's a part of the diesel engine's emission control system that manages the injection of diesel exhaust fluid.
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