AutoCodes – GMC – P20BD 2016 GMC Sierra

P20BD 2016 GMC Sierra Code - Reductant Heater 2 Control Circuit

Quick Answer

As reductant will freeze at temperatures below -11°C (12°F), there are 2 reductant heaters located in the reductant tank. Common causes include Faulty Reductant Heater, Reductant Heater harness is open or shorted, Reductant Heater circuit poor electrical connection. 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: P20BD 2016 GMC Sierra indicates Reductant Heater 2 Control Circuit.
Common causes: Common causes include Faulty Reductant Heater, Reductant Heater harness is open or shorted, Reductant Heater circuit poor electrical connection.
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.

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Code Popularity 404

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 29, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P20BD 2016 GMC Sierra Description

As reductant will freeze at temperatures below -11°C (12°F), there are 2 reductant heaters located in the reductant tank. One heats the reductant in the tank, and one heats the reductant supplied to the reductant injector supply pipe. The Engine Control Module (ECM) monitors the reductant temperature in the tank in order to determine if the reductant temperature is below its freeze point. If the ECM determines that the reductant may be frozen, it activates a "defrost strategy" energizing the reductant eater. This energizing action terminates when the temperature sensor measures a threshold value over which the heater must be deactivated.
The Diagnostic Trouble Code (DTC) will be set when the ECM indicates the reductant line heater control circuit is open for greater than 4 s.

OBDII Code P20BD 2016 GMC Sierra - Reductant Heater 2 Control Circuit - AutoCodes.com — P20BD 2016 GMC Sierra Code - Reductant Heater 2 Control Circuit

What does this mean?

What are the Possible Causes of the DTC P20BD 2016 GMC Sierra?

Faulty Reductant Heater
Reductant Heater harness is open or shorted
Reductant Heater circuit poor electrical connection
Faulty Reductant Pump and Sensor Assembly
Faulty Reductant Control Module

How to Fix the DTC P20BD 2016 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P20BD 2016 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P20BD 2016 GMC Sierra code?

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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 P20BD 2016 GMC Sierra Code

1. What does the OBDII code P20BD mean on a 2016 GMC Sierra?

The P20BD code indicates a problem with the Reductant Heater 2 Control Circuit, responsible for heating the diesel exhaust fluid (DEF) to ensure proper operation in cold temperatures.

2. What are the symptoms of the P20BD code on a GMC Sierra?

Common symptoms include a check engine light, possible DEF system warnings, reduced engine power, or difficulty in maintaining DEF fluid temperature during cold weather.

3. What causes the P20BD code on a 2016 GMC Sierra?

Typical causes include a faulty reductant heater, damaged wiring or connectors in the heater circuit, or a malfunctioning powertrain control module (PCM).

4. Can I continue driving with the P20BD code on my GMC Sierra?

While you can drive with this code, ignoring it may lead to DEF system issues, reduced engine performance, or difficulty passing emissions tests.

5. How is the P20BD code diagnosed?

A mechanic will use a diagnostic scanner to confirm the code, inspect the reductant heater, check wiring and connectors, and test the circuit for proper voltage and resistance.

6. How do you fix the P20BD code on a GMC Sierra?

Repairs may involve replacing the reductant heater, repairing or replacing damaged wiring or connectors, or, in rare cases, reprogramming or replacing the PCM.

7. What is the function of the reductant heater in the DEF system?

The reductant heater warms the diesel exhaust fluid in cold temperatures to prevent it from freezing and ensure proper delivery to the SCR system.

8. How much does it cost to fix the P20BD code on a GMC Sierra?

Repair costs vary but typically range from $200 to $800, depending on whether the reductant heater, wiring, or other components need replacement.

9. Can a faulty reductant heater affect emissions on a GMC Sierra?

Yes, a malfunctioning reductant heater can prevent proper DEF delivery, which may lead to increased emissions and failure to meet regulatory standards.

10. Is the P20BD code covered under warranty for a 2016 GMC Sierra?

Depending on mileage and warranty coverage, this issue may be covered under the emissions system warranty. Check with your dealer for specific details.