Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's system that helps reduce pollution is having trouble because a part that controls it is stuck in the 'on' position.
The reductant pump is part of the vehicle's Selective Catalytic Reduction (SCR) system, which helps reduce emissions. This code indicates that the supply voltage to the pump is stuck in the 'on' position, meaning it is not turning off when it should.
The P05F1 code is triggered when the Engine Control Module (ECM) detects that the reductant pump supply voltage circuit is stuck in the 'on' position. This can be due to a fault in the pump, wiring, or ECM itself. The reductant pump is responsible for delivering diesel exhaust fluid (DEF) to the SCR catalyst to reduce NOx emissions.
• Check Engine Light is on
• Possible reduction in engine performance
• Increased emissions
• Faulty reductant pump
• Wiring issues in the reductant pump circuit
• Faulty Engine Control Module (ECM)
Reductant Pump: A component that delivers diesel exhaust fluid to the SCR system.
SCR: Selective Catalytic Reduction, a system used to reduce NOx emissions in diesel engines.
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors of the reductant pump circuit.
• Test the reductant pump for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the reductant pump if faulty.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $800
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regularly check and maintain the DEF system.
• Inspect wiring and connectors for damage.
• Ensure the ECM software is up to date.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Regular maintenance can prevent this issue.
Check with the vehicle manufacturer for specific warranty coverage related to emissions systems.
This code is relatively common in vehicles equipped with SCR systems, particularly in diesel engines.
Moderate – It is important to address this issue to maintain emissions compliance and avoid potential engine performance issues.
Driving with this code may result in failing emissions tests and could lead to fines in areas with strict emissions regulations.
• Engine running
• Vehicle at operating temperature
The reductant pump is typically located near the DEF tank, often at the rear of the vehicle.
Q: Can I drive with a P05F1 code?
A: While the vehicle may still be drivable, it's best to address the issue to avoid increased emissions and potential engine performance problems.
Q: How can I prevent this code from appearing?
A: Regular maintenance of the DEF system and ensuring all software updates are applied can help prevent this issue.
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
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Fitment Required · Vehicle-fitment part
Relevant when catalyst-efficiency or emissions faults persist after proper diagnosis.
Catalyst-efficiency faults sometimes point toward converter problems after proper testing.
Catalytic converters are highly vehicle-specific and should not be purchased by code alone.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.