Engine-CodesGMC – P2056 GMC

P2056 GMC Code - Reductant Injection Valve Circuit/Open Bank 2 Unit 2

Quick Answer

The P2056 diagnostic trouble code for GMC vehicles relates to the reductant injection valve circuit being open on Bank 2 Unit 2. Common causes include Faulty reductant injection valve, Damaged wiring or connectors, Blown fuse related to the DEF system. 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
P2056 GMC indicates Reductant Injection Valve Circuit/Open Bank 2 Unit 2.
Common causes
Common causes include Faulty reductant injection valve, Damaged wiring or connectors, Blown fuse related to the DEF system.
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 08, 2024
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Code P2056 GMC Description

The P2056 diagnostic trouble code for GMC vehicles relates to the reductant injection valve circuit being open on Bank 2 Unit 2. This code specifically pertains to the diesel exhaust fluid (DEF) system, which is responsible for reducing harmful emissions from the vehicle's exhaust system. The reductant injection valve is a crucial component of the DEF system, as it controls the flow of DEF into the exhaust stream to help convert nitrogen oxides (NOx) into harmless nitrogen and water vapor.

OBDII Code P2056 GMC - Reductant Injection Valve Circuit/Open Bank 2 Unit 2
P2056 GMC Code - Reductant Injection Valve Circuit/Open Bank 2 Unit 2

Common Causes of P2056 GMC

  1. Faulty reductant injection valve
  2. Damaged wiring or connectors
  3. Blown fuse related to the DEF system
  4. Defective DEF pump
  5. ECM (Engine Control Module) issues

Symptoms of P2056 GMC

  1. Check Engine Light illuminated
  2. Reduced engine performance
  3. Decreased fuel efficiency
  4. Failed emissions test
  5. Rough idling or stalling

How to Fix P2056 GMC

  1. Begin by performing a thorough inspection of the reductant injection valve, wiring, and connectors for any visible damage or corrosion.
  2. Test the reductant injection valve and related components using a multimeter to check for proper electrical continuity.
  3. Replace the reductant injection valve if it is found to be faulty, making sure to follow manufacturer specifications for installation.
  4. Clear the diagnostic trouble codes from the vehicle's ECM and reset the system to see if the issue has been resolved.
  5. Test drive the vehicle to ensure that the P2056 code does not return and that the vehicle's emissions and performance are back to normal.

Cost to Fix P2056 GMC

The typical repair costs for addressing the P2056 code on a GMC vehicle can vary depending on the specific cause of the issue and the cost of parts and labor in your area. However, as a rough estimate, you can expect to pay anywhere from $200 to $500 for parts and labor. Keep in mind that diagnosis time and labor rates at auto repair shops can vary, so it's recommended to obtain quotes from multiple sources to get a more accurate estimate for your particular situation.

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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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