Engine-CodesGMC – P20E8 2016 GMC Sierra

P20E8 2016 GMC Sierra Code - Reductant Low Pressure

Quick Answer

The P20E8 diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a problem with the reductant low-pressure system. Common causes include Leaking reductant lines or connections, Malfunctioning reductant pressure sensor, Clogged reductant filter. 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
P20E8 2016 GMC Sierra indicates Reductant Low Pressure.
Common causes
Common causes include Leaking reductant lines or connections, Malfunctioning reductant pressure sensor, Clogged reductant filter.
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 P20E8 2016 GMC Sierra Description

The P20E8 diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a problem with the reductant low-pressure system. In vehicles equipped with Selective Catalytic Reduction (SCR) systems, reductant is injected into the exhaust stream to help reduce harmful emissions. The reductant, typically a solution of urea and water known as Diesel Exhaust Fluid (DEF), is stored in a dedicated tank and injected into the exhaust system as needed.

OBDII Code P20E8 2016 GMC Sierra - Reductant Low Pressure
P20E8 2016 GMC Sierra Code - Reductant Low Pressure

Common Causes of P20E8 2016 GMC Sierra

  1. Leaking reductant lines or connections
  2. Malfunctioning reductant pressure sensor
  3. Clogged reductant filter
  4. Faulty reductant pump
  5. DEF contamination

Symptoms of P20E8 2016 GMC Sierra

  1. Check Engine Light illuminated
  2. Reduced engine performance
  3. Poor fuel economy
  4. Increased exhaust emissions
  5. Reduced DEF consumption

How to Fix P20E8 2016 GMC Sierra

  1. Diagnose the system using a scan tool to pinpoint the exact cause of the low-pressure issue.
  2. Inspect reductant lines, connections, and components for leaks or damage.
  3. Test the reductant pressure sensor and replace if necessary.
  4. Check and replace the reductant filter if clogged.
  5. Inspect the reductant pump for proper operation and replace if faulty.

Cost to Fix P20E8 2016 GMC Sierra

The cost of repairing a P20E8 code on a 2016 GMC Sierra can vary depending on the specific cause of the issue. In general, parts such as a reductant pressure sensor, reductant filter, or reductant pump can range from $50 to $200 each. Labor costs at an auto repair shop can add an additional $100 to $300 or more, depending on the shop's hourly rates. Overall, the total cost of repairing a reductant low-pressure issue could range from $200 to $800 or more. It's advisable to get a detailed estimate from a qualified mechanic to determine the exact cost for your specific vehicle.

Tech Notes for P20E8 2016 GMC Sierra









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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.

Frequently Asked Questions about P20E8 2016 GMC Sierra Code

1. What does the OBDII code P20E8 mean on a 2016 GMC Sierra?

The P20E8 code indicates "Reductant Pressure Too Low," which means the diesel exhaust fluid (DEF) system is not maintaining sufficient pressure for proper operation.

2. What are the common symptoms of the P20E8 code on a 2016 GMC Sierra?

Symptoms include a Check Engine Light, DEF system warnings, reduced engine power, and possibly a countdown to limited vehicle operation.

3. What causes the P20E8 code on a 2016 GMC Sierra?

Common causes include a failing DEF pump, clogged filters or lines, low DEF fluid levels, or electrical issues within the reductant system.

4. Can a clogged DEF filter cause the P20E8 code?

Yes, a clogged or restricted DEF filter can reduce pressure in the system and trigger the P20E8 code.

5. How do you diagnose the P20E8 code on a 2016 GMC Sierra?

Diagnosis involves checking DEF fluid levels, inspecting the DEF pump and pressure sensor, testing for clogs in the lines or filters, and running a system scan for additional related codes.

6. Can driving with the P20E8 code damage the vehicle?

Continuing to drive with this code can lead to reduced engine performance and may eventually cause the vehicle to enter a "limp mode" or become inoperable.

7. How is the P20E8 code fixed on a 2016 GMC Sierra?

Repairs typically involve replacing the DEF pump, cleaning or replacing filters, flushing the DEF lines, or addressing electrical faults in the reductant system.

8. Does low DEF fluid cause the P20E8 code?

Low DEF levels can contribute to pressure issues, but the code usually points to a mechanical or electrical fault within the reductant system.

9. How much does it cost to repair the P20E8 code on a 2016 GMC Sierra?

Repair costs vary but replacing the DEF pump can range from $500 to $1,000, while simpler fixes like cleaning the filter may cost less.

10. Can resetting the Check Engine Light fix the P20E8 code?

Resetting the light may temporarily clear the code, but the underlying issue must be resolved to prevent the code from returning.

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