P20FD – Reductant Quality Sensor Circuit Range/Performance

Urgency and Severity

The P20FD diagnostic trouble code (DTC) indicates an issue with the reductant pump control circuit in the vehicle's emissions control system. While not immediately critical, this code should be addressed promptly to prevent potential damage to the emissions system and ensure compliance with emissions regulations.

Severity Level: Moderate
Continued Driving: Generally safe for short distances, but prolonged driving is not recommended
Dealer Visit: Not immediately required, but should be scheduled soon

Code Details

P20FD is defined as "Reductant Pump 'B' Control Circuit High". This code is:

• Powertrain-related (P)
• Manufacturer-controlled (2)
• Related to fuel and air metering auxiliary emission controls (0)

The code is generally manufacturer-specific, meaning its exact interpretation may vary slightly between vehicle makes and models.

Components Involved

The primary component involved is Reductant Pump 'B', which is part of the Selective Catalytic Reduction (SCR) system used in diesel engines to reduce NOx emissions.

Reductant Pump 'B' Function:

• Delivers Diesel Exhaust Fluid (DEF) to the SCR catalyst
• Precisely controls DEF injection for optimal NOx reduction

Related SCR System Components:

• DEF tank
• DEF injector
• SCR catalyst
• NOx sensors

Common Causes

1. Electrical issues in the pump control circuit (most common)

   • Short circuit to power
   • Wiring harness damage
   • Connector corrosion

2. Faulty reductant pump

3. DEF quality issues or contamination
4. ECU software issues

Diagnostic Procedure

Tools Required:

• OBD-II scanner
• Digital multimeter
• Wiring diagrams for the specific vehicle model

Steps:

1. Connect the OBD-II scanner and confirm the P20FD code
2. Check for any additional related codes (e.g., P20FA, P20FC)
3. Inspect the DEF system for visible damage or leaks
4. Check DEF quality and level
5. Examine wiring and connectors for damage or corrosion
6. Use a multimeter to test the reductant pump circuit:
   • Check for proper voltage supply (typically 12V)
   • Measure resistance in the control circuit (refer to manufacturer specifications)
7. Test the reductant pump operation using the scanner's bidirectional controls

Solutions

1. Repair or replace damaged wiring
2. Clean or replace corroded connectors
3. Replace faulty reductant pump
4. Update ECU software if a known issue exists
5. Flush and refill DEF system if contamination is found

Prevention

• Regular DEF system maintenance
• Use high-quality DEF fluid
• Protect wiring harnesses from environmental damage
• Address check engine lights promptly

Cost Analysis

Estimated repair costs (USD/EUR):

• Wiring repair: $100-300 / €85-255
• Connector replacement: $50-150 / €42-127
• Reductant pump replacement: $300-800 / €255-680
• ECU software update: $100-200 / €85-170

DIY Repair Guide

Warning: Only attempt if you have experience with automotive electrical systems.

1. Disconnect the vehicle battery
2. Locate the reductant pump (refer to service manual)
3. Inspect and test wiring using a multimeter
4. Replace pump if faulty (follow manufacturer's removal/installation procedure)
5. Clear DTCs and perform a system relearn procedure

Related Issues

• P20FA (Reductant Pump Control Circuit)
• P20FC (Reductant Pump Control Circuit Low)
• U02A2 (Lost Communication with Reductant Control Module)

Technical Specifications

• Typical reductant pump operating voltage: 12V DC
• DEF flow rate: 0.1 – 1.5 L/min (depending on engine size and load)
• DEF freezing point: -11°C (12°F)

Remember to always consult the specific vehicle's service manual for exact specifications and procedures, as they may vary between makes and models.

Frequently Asked Questions About P20FD

What does the P20FD code mean?

P20FD stands for “Reductant Pump ‘B’ Control Circuit High”. It indicates an issue with the control circuit for the diesel exhaust fluid (DEF) pump in the vehicle’s selective catalytic reduction (SCR) system.

How urgent is it to address the P20FD code?

While not immediately critical, the P20FD code should be addressed promptly to prevent potential damage to the emissions system and ensure compliance with emissions regulations. It’s generally safe to drive short distances, but prolonged driving is not recommended.

Is P20FD a generic or manufacturer-specific code?

P20FD is typically a manufacturer-specific code, meaning its exact interpretation may vary slightly between vehicle makes and models.

What components are involved with the P20FD code?

The primary component is Reductant Pump ‘B’, which is part of the SCR system. Related components include the DEF tank, DEF injector, SCR catalyst, and NOx sensors.

What are common causes of the P20FD code?

Common causes include electrical issues in the pump control circuit (e.g., short circuit to power, wiring harness damage, connector corrosion), a faulty reductant pump, DEF quality issues or contamination, and ECU software issues.

What tools are needed to diagnose the P20FD code?

Essential tools include an OBD-II scanner, digital multimeter, and wiring diagrams for the specific vehicle model.

What are the steps to diagnose the P20FD code?

Key steps include confirming the code with an OBD-II scanner, checking for related codes, inspecting the DEF system, checking DEF quality and level, examining wiring and connectors, and testing the reductant pump circuit and operation.

How can I fix the P20FD code?

Solutions may include repairing or replacing damaged wiring, cleaning or replacing corroded connectors, replacing a faulty reductant pump, updating ECU software, or flushing and refilling the DEF system if contamination is found.

How can I prevent the P20FD code from occurring?

Prevention measures include regular DEF system maintenance, using high-quality DEF fluid, protecting wiring harnesses from environmental damage, and addressing check engine lights promptly.

What is the estimated cost to repair issues related to the P20FD code?

Repair costs can vary widely depending on the specific issue. Estimates range from $50-150 for connector replacement to $300-800 for reductant pump replacement.

Can I drive my vehicle with the P20FD code active?

While it’s generally safe for short distances, prolonged driving with the P20FD code active is not recommended as it may lead to further damage or emissions non-compliance.

Will the P20FD code clear itself?

The code will typically not clear itself. It usually needs to be cleared with an OBD-II scanner after the underlying issue has been resolved.

What other codes are commonly associated with P20FD?

Related codes often include P20FA (Reductant Pump Control Circuit), P20FC (Reductant Pump Control Circuit Low), and U02A2 (Lost Communication with Reductant Control Module).

How does the reductant pump relate to vehicle emissions?

The reductant pump delivers Diesel Exhaust Fluid (DEF) to the SCR catalyst, which is crucial for reducing NOx emissions in diesel engines.

Can low-quality DEF cause the P20FD code?

Yes, using low-quality or contaminated DEF can potentially lead to issues with the reductant pump and trigger the P20FD code.

Is it safe to attempt DIY repairs for the P20FD code?

While some repairs can be done by experienced DIYers, it’s generally recommended to have a professional diagnose and repair issues related to the P20FD code due to the complexity of modern emissions systems.

How long does it typically take to diagnose and repair a P20FD code issue?

Diagnosis time can vary, but typically takes 1-2 hours. Repair time depends on the specific issue, ranging from 30 minutes for simple electrical repairs to several hours for pump replacement.

Can extreme weather conditions trigger the P20FD code?

While not directly, extreme cold can cause DEF to freeze, potentially damaging the pump or related components, which could lead to a P20FD code.

Will a P20FD code affect my vehicle’s performance?

In most cases, you may not notice immediate performance issues. However, if left unaddressed, it could lead to reduced engine performance or even engine derating as an emissions compliance measure.

How often should I have my vehicle’s DEF system checked to prevent P20FD issues?

It’s recommended to have the DEF system checked during regular maintenance intervals, typically every 15,000 to 20,000 miles or as specified in your vehicle’s owner manual.