P2059 Code: Complete DIY Repair Guide

The P2059 trouble code indicates a malfunction in the reductant injection air pump control circuit. This code is part of the OBD-II diagnostic system, which monitors various components of a vehicle’s engine and emissions systems to ensure they are functioning correctly. When the powertrain control module (PCM) detects an open circuit in the reductant injection air pump control circuit, it triggers this code. The reductant system is essential for reducing nitrogen oxide (NOx) emissions in diesel engines, and any issues can lead to increased emissions and potential damage to the vehicle’s exhaust system.

Symptoms of P2059 Code

When a vehicle triggers the P2059 code, several symptoms may manifest, indicating that there is a problem with the reductant injection system:

• Check Engine Light: The most immediate symptom is the illumination of the check engine light on the dashboard.
• Reduced Engine Performance: Drivers may notice a decrease in engine power, especially under load conditions.
• Poor Fuel Efficiency: A malfunctioning reductant system can lead to increased fuel consumption as the engine compensates for reduced efficiency.
• Excessive Emissions: The vehicle may produce more black smoke from the exhaust due to incomplete combustion.
• Failed Emissions Tests: Vehicles equipped with OBD-II systems may fail emissions tests if this code is present, as it indicates a failure in the emissions control system.

Technical Explanation of P2059 Code

The P2059 code specifically relates to the reductant injection air pump control circuit within the selective catalytic reduction (SCR) system. This system is crucial for reducing harmful NOx emissions from diesel engines.

The reductant injection air pump is responsible for pressurizing diesel exhaust fluid (DEF), which is injected into the exhaust stream. This process helps convert NOx into harmless nitrogen and water vapor. If there is an open circuit in this control line, it means that the PCM cannot communicate properly with the pump, leading to potential failures in emission control.

Common issues that lead to this code include:

• Electrical Failures: Open or shorted circuits can disrupt communication between components.
• Sensor Malfunctions: A faulty reductant air pressure sensor can send incorrect signals to the PCM, causing it to trigger this code.
• Pump Failures: If the reductant injection air pump itself fails, it will not operate correctly, leading to emission issues.

Step-by-Step Diagnosis of P2059 Code

Diagnosing a P2059 trouble code involves several steps:

1. Initial Scan: Use an OBD-II scanner to retrieve all stored codes and freeze frame data. Document these codes for further analysis.
2. Visual Inspection: Check for obvious signs of damage or corrosion on wiring and connectors related to the reductant injection system.
3. Test Voltage and Ground: Using a digital volt/ohmmeter (DVOM), test for proper voltage and ground at the reductant injection air pump connector.
4. Check Sensor Functionality: Test the reductant air pressure sensor for proper operation. It should provide readings within manufacturer specifications.
5. Inspect Pump Operation: Activate the pump using a scan tool or by applying power directly to see if it operates correctly.
6. Wiring Integrity Test: Check all wiring between components for continuity and resistance to ensure there are no breaks or shorts.
7. Clear Codes and Test Drive: After repairs, clear any codes and take the vehicle for a test drive to see if the P2059 code reappears.

Solution Methods for P2059 Code

Several methods can be employed to resolve issues associated with the P2059 trouble code:

• Repair or Replace Faulty Components:
• If testing reveals a defective reductant injection air pump, replace it.
• Repair or replace corroded connectors or damaged wiring harnesses.
• Sensor Replacement:
• If the reductant air pressure sensor is faulty, replace it with a new one that meets OEM specifications.
• PCM Reprogramming/Replacement:
• In cases where all other components are functioning correctly but the code persists, consider reprogramming or replacing the PCM.
• Regular Maintenance Checks:
• Ensure regular maintenance of emission systems can prevent future occurrences of this code.

Cost Estimates

The cost of diagnosing and repairing a P2059 trouble code can vary widely based on location and vehicle make/model:

• Diagnostic Fees: Typically range from $75 to $150 depending on labor rates at local shops.
• Parts Replacement Costs:
• Reductant injection air pump: $200 – $600
• Reductant air pressure sensor: $50 – $150
• Wiring repairs may vary based on extent but could range from $50 – $300.

Overall repair costs could range from $200 to over $1,000 depending on parts needed and labor involved.

Warnings and Recommendations

• Always ensure that you are using OEM parts when replacing components in your emissions system to maintain compliance with regulations.
• If you are not confident in diagnosing or repairing electrical systems, it is advisable to seek professional help. Electrical issues can be complex and may require specialized tools and knowledge.

Closing Paragraph

The P2059 trouble code signifies an issue within your vehicle’s reductant injection system that requires immediate attention. Understanding its implications can help you maintain your vehicle’s performance while ensuring compliance with emission standards. Regular diagnostics and timely repairs not only enhance your vehicle’s efficiency but also contribute positively to environmental conservation efforts. Always consult your vehicle’s service manual for specific guidelines related to your make and model when addressing such codes.

Frequently Asked Questions About P2059

• What does P2059 mean?
  The P2059 code indicates an open circuit in the reductant injection air pump control circuit, affecting your vehicle’s emissions control system.
• How serious is a P2059 code?
  A P2059 code should be treated seriously as it can lead to increased emissions and potential damage to your vehicle’s exhaust components.
• Can I drive my car with a P2059 code?
  While you may be able to drive short distances, it’s advisable not to ignore this code as it could worsen emissions problems.
• What are common symptoms of a P2059 code?
  Common symptoms include reduced engine performance, poor fuel efficiency, excessive smoke from exhaust, and illumination of the check engine light.
• How do I fix a P2059 code?
  Fixing this code typically involves inspecting wiring and connectors, testing sensors, replacing faulty components like pumps or sensors, and ensuring all connections are secure.
• Will clearing my codes fix my car?
  No, simply clearing codes will not fix underlying issues; proper diagnosis and repair are necessary.
• How much does it cost to fix a P2059 code?
  The cost can range from $200 to over $1,000 depending on parts needed and labor involved.
• When should I seek professional help for a P2059 code?
  If you’re unsure about diagnosing electrical issues or if repairs don’t resolve the problem after several attempts, it’s best to consult a professional mechanic.