AutoCodes – GMC – P20B9 2014 GMC Sierra

P20B9 2014 GMC Sierra Code - Reductant Heater 1 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: P20B9 2014 GMC Sierra indicates Reductant Heater 1 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 211

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 P20B9 2014 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 tank heater control circuit is open for greater than 4 s.

OBDII Code P20B9 2014 GMC Sierra - Reductant Heater 1 Control Circuit - AutoCodes.com — P20B9 2014 GMC Sierra Code - Reductant Heater 1 Control Circuit

What does this mean?

What are the Possible Causes of the DTC P20B9 2014 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 P20B9 2014 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 P20B9 2014 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 P20B9 2014 GMC Sierra code?

Need more information on how to fix the P20B9 2014 GMC Sierra code? Get Access to Factory Service Manuals

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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 P20B9 2014 GMC Sierra Code

What does the OBDII code P20B9 mean on a 2014 GMC Sierra?

P20B9 indicates an issue with the Reductant Heater 1 Control Circuit, which is responsible for heating the diesel exhaust fluid (DEF) to ensure proper operation in cold temperatures.

What are the common symptoms of code P20B9 on a 2014 GMC Sierra?

Symptoms may include the check engine light turning on, DEF system warnings, reduced engine performance, and difficulty maintaining DEF system functionality in cold weather.

What causes code P20B9 on a 2014 GMC Sierra?

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

How can I diagnose code P20B9 on my 2014 GMC Sierra?

Use an OBDII scanner to confirm the code, inspect the reductant heater and related wiring for damage, and test the heater circuit for proper voltage and continuity.

Can I still drive my 2014 GMC Sierra with code P20B9 active?

While the vehicle may be drivable, ignoring this code could lead to DEF system failure, reduced engine performance, or inability to meet emissions standards, especially in cold weather.

How is code P20B9 typically repaired on a 2014 GMC Sierra?

Repairs may include replacing the reductant heater, repairing or replacing damaged wiring, and resetting the PCM after the repair.

How much does it cost to fix code P20B9 on a 2014 GMC Sierra?

Repair costs vary depending on the exact issue but can range from $200 to $500 for parts and labor, with higher costs if the PCM needs replacement.

Can code P20B9 be caused by extreme weather conditions?

Yes, cold weather can exacerbate issues with the reductant heater system, especially if the heater or wiring is already compromised.

What tools are needed to fix code P20B9 on a 2014 GMC Sierra?

Basic tools include an OBDII scanner, multimeter for testing circuits, and possibly replacement parts like a new reductant heater or wiring components.

Will clearing the code P20B9 fix the problem on my 2014 GMC Sierra?

Clearing the code without addressing the underlying issue will not resolve the problem and the code is likely to return. Proper diagnosis and repair are necessary.