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 a problem with its power supply. It's like when a toy doesn't work because the batteries are low.
The P056D code indicates an issue with the voltage supply to the reductant control module, which is responsible for managing the diesel exhaust fluid system.
The reductant control module is responsible for controlling the injection of diesel exhaust fluid (DEF) into the exhaust system to reduce emissions. This code is triggered when the module detects an abnormal voltage level, either too high or too low, which can affect its operation.
• Check Engine Light is on
• Possible reduction in engine performance
• Emission test failure
• Faulty reductant control module
• Wiring issues (short or open circuit)
• Poor electrical connections
Reductant: A substance used to reduce emissions in diesel engines.
DEF: Diesel Exhaust Fluid, a fluid used to reduce emissions.
• Read the OBD-II codes using a scanner.
• Inspect the wiring and connectors to the reductant control module.
• Test the battery and charging system for proper voltage.
• Replace or repair faulty wiring or connectors.
• Replace the reductant control module if necessary.
• Ensure the battery and charging system are functioning correctly.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regularly check and maintain battery health.
• Inspect wiring and connectors periodically.
• Ensure the charging system is functioning properly.
Sensor Issue
• Avoid driving long distances until the issue is resolved.
• Have a professional mechanic inspect the vehicle.
Check with the manufacturer for warranty coverage on emission-related components.
This code has become more common with the increased use of DEF systems in diesel vehicles to meet emission standards.
Moderate – It should be addressed soon to avoid potential damage to the emission system.
Ignoring emission-related issues may lead to failing emissions tests and potential fines.
• Engine running
• Vehicle at operating temperature
The reductant control module is typically located near the DEF tank or integrated into the engine control module.
Q: Can I drive with a P056D code?
A: It's not recommended as it may lead to increased emissions and potential engine performance issues.
Q: How do I clear a P056D code?
A: After repairs, use an OBD-II scanner to clear the code, but ensure the issue is resolved first.
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