Engine-CodesGeneric – P20B7

P20B7 Code - Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Low

Quick Answer

The P20B7 diagnostic trouble code (DTC) refers to an issue with the Diesel Exhaust Fluid (DEF) reductant pump heater control circuit being detected as lower than normal. Common causes include Faulty Reductant Pump Heater Element: The heater element within the reductant pump may be faulty, causing it to operate below the required voltage levels, Wiring Issues: Damage to the wiring harness or connectors associated with the reductant pump heater control circuit can lead to a low voltage condition, Faulty Relay: A malfunctioning relay that controls the power supply to the reductant pump heater can result in the circuit operating at lower than normal voltage levels. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P20B7 indicates Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Low.
Common causes
Common causes include Faulty Reductant Pump Heater Element: The heater element within the reductant pump may be faulty, causing it to operate below the required voltage levels, Wiring Issues: Damage to the wiring harness or connectors associated with the reductant pump heater control circuit can lead to a low voltage condition, Faulty Relay: A malfunctioning relay that controls the power supply to the reductant pump heater can result in the circuit operating at lower than normal voltage levels.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 09, 2024
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Code P20B7 Description

The P20B7 diagnostic trouble code (DTC) refers to an issue with the Diesel Exhaust Fluid (DEF) reductant pump heater control circuit being detected as lower than normal. This code is commonly found in vehicles equipped with a Selective Catalytic Reduction (SCR) system, which helps reduce harmful emissions by injecting DEF into the exhaust stream. The reductant pump heater is responsible for maintaining the DEF at the optimal temperature for proper operation.

OBDII Code P20B7 - Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Low
P20B7 Code - Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Low

Common Causes of P20B7

  1. Faulty Reductant Pump Heater Element: The heater element within the reductant pump may be faulty, causing it to operate below the required voltage levels.
  2. Wiring Issues: Damage to the wiring harness or connectors associated with the reductant pump heater control circuit can lead to a low voltage condition.
  3. Faulty Relay: A malfunctioning relay that controls the power supply to the reductant pump heater can result in the circuit operating at lower than normal voltage levels.
  4. ECM Malfunction: An issue with the Engine Control Module (ECM) may also trigger this DTC, as it is responsible for monitoring and controlling the reductant pump heater circuit.

Symptoms of P20B7

  1. Illuminated Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced DEF System Performance: The vehicle may experience reduced performance of the DEF system, leading to decreased fuel efficiency and potential emissions compliance issues.
  3. Failed Emissions Test: If the issue is not addressed, the vehicle may fail emissions testing, as the SCR system may not be functioning properly.
  4. Reduced Engine Power: In severe cases, the vehicle may go into a reduced power mode to protect the engine and emissions system.

How to Fix P20B7

  1. Diagnose the Issue: Use a scan tool to retrieve the DTC and perform a thorough inspection of the reductant pump heater circuit to identify the root cause of the low voltage condition.
  2. Test the Heater Element: Check the resistance of the heater element to determine if it is within the manufacturer's specifications. Replace if necessary.
  3. Inspect Wiring and Connectors: Check for any signs of damage, corrosion, or loose connections in the wiring harness and connectors. Repair or replace as needed.
  4. Test the Relay: Check the relay that controls the reductant pump heater circuit for proper operation. Replace if found to be faulty.
  5. Clear DTC and Test Drive: Once the repairs have been completed, clear the DTC from the ECM's memory and test drive the vehicle to ensure that the issue has been resolved.

Cost to Fix P20B7

The typical repair cost for addressing a P20B7 DTC can range from $200 to $500, including parts and labor. However, it's important to note that the specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's recommended to check with local shops for a more accurate estimate. Remember that rates at dealerships or in metropolitan areas may be higher, while independent shops may offer more affordable prices.

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Code P20B7 Information for Specific Makes

  • P20B7 Dodge — Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Low
  • P20B7 RAM — Diesel Exhaust Fluid Reductant Pump Heater Control Circuit Low
About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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