Engine-CodesGeneric – P2051

P2051 Code - Reductant Injection Valve Circuit Low Bank 2 Unit 1

Quick Answer

The diagnostic trouble code P2051 indicates a problem with the reductant injection valve circuit on Bank 2 Unit 1 of the vehicle's exhaust system. Common causes include Faulty Reductant Injection Valve: The reductant injection valve itself may be malfunctioning, causing low voltage in the circuit, Damaged Wiring: A damaged or corroded wire in the circuit can lead to a loss of voltage and trigger the P2051 code, ECM Malfunction: A problem with the Engine Control Module (ECM) could prevent proper communication with the reductant injection valve. 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
P2051 indicates Reductant Injection Valve Circuit Low Bank 2 Unit 1.
Common causes
Common causes include Faulty Reductant Injection Valve: The reductant injection valve itself may be malfunctioning, causing low voltage in the circuit, Damaged Wiring: A damaged or corroded wire in the circuit can lead to a loss of voltage and trigger the P2051 code, ECM Malfunction: A problem with the Engine Control Module (ECM) could prevent proper communication with the reductant injection valve.
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 10, 2024
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Code P2051 Description

The diagnostic trouble code P2051 indicates a problem with the reductant injection valve circuit on Bank 2 Unit 1 of the vehicle's exhaust system. This code is typically associated with diesel engines equipped with a Selective Catalytic Reduction (SCR) system. The reductant injection valve is responsible for injecting a urea-based solution (commonly known as AdBlue) into the exhaust stream to reduce harmful emissions of nitrogen oxides.

OBDII Code P2051 - Reductant Injection Valve Circuit Low Bank 2 Unit 1
P2051 Code - Reductant Injection Valve Circuit Low Bank 2 Unit 1

Common Causes of P2051

  1. Faulty Reductant Injection Valve: The reductant injection valve itself may be malfunctioning, causing low voltage in the circuit.
  2. Damaged Wiring: A damaged or corroded wire in the circuit can lead to a loss of voltage and trigger the P2051 code.
  3. ECM Malfunction: A problem with the Engine Control Module (ECM) could prevent proper communication with the reductant injection valve.
  4. Electrical Connection Issues: Loose or poor electrical connections to the reductant injection valve can result in low voltage readings.

Symptoms of P2051

  1. Check Engine Light: The most common symptom associated with a P2051 code is the illumination of the Check Engine Light on the vehicle's dashboard.
  2. Reduced Power: The vehicle may experience a loss of power or performance due to the malfunctioning reductant injection valve.
  3. Poor Fuel Efficiency: An increase in fuel consumption may occur as a result of the engine compensating for the emission control system's inefficiency.
  4. Failed Emissions Test: If the vehicle is subjected to an emissions test, it may fail to meet the required standards due to increased nitrogen oxide emissions.

How to Fix P2051

  1. Diagnose the Issue: Use a diagnostic scan tool to retrieve the fault code and perform a thorough inspection of the reductant injection valve circuit.
  2. Test the Reductant Injection Valve: Check the functionality of the reductant injection valve to determine if it needs to be replaced.
  3. Inspect Wiring: Inspect the wiring harness for any damage or corrosion, and repair or replace as necessary.
  4. Check Electrical Connections: Ensure all electrical connections to the reductant injection valve are secure and free of debris.
  5. Clear Codes: After completing the repairs, clear the fault code from the ECM using a scan tool and test drive the vehicle to verify that the issue has been resolved.

Cost to Fix P2051

The cost of repairing a P2051 code can vary depending on the specific cause of the issue and the vehicle's make and model. In general, replacing a faulty reductant injection valve can cost anywhere from $200 to $500, while repairing damaged wiring or electrical connections may range from $100 to $300. Labor costs at auto repair shops typically range between $80 and $150 per hour, so the total cost for diagnosing and repairing a P2051 code can be estimated at $300 to $800. It is recommended to obtain quotes from local repair shops to get a more accurate cost estimate based on your specific circumstances.

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Code P2051 Information for Specific Makes

  • P2051 Chevrolet — Reductant Injection Valve Circuit Low Bank 2 Unit 1
  • P2051 Dodge — Reductant Injection Valve Circuit Low Bank 2 Unit 1
  • P2051 Ford — Reductant Injection Valve Circuit Low Bank 2 Unit 1
  • P2051 GMC — Reductant Injection Valve Circuit Low Bank 2 Unit 1
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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