AutoCodes – GMC – P20C0 2017 GMC Sierra

P20C0 2017 GMC Sierra Code - Reductant Heater 2 Control Circuit High Voltage

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: P20C0 2017 GMC Sierra indicates Reductant Heater 2 Control Circuit High Voltage.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 165

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P20C0 2017 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 shorted to a voltage for greater than 4 s.

OBDII Code P20C0 2017 GMC Sierra - Reductant Heater 2 Control Circuit High Voltage - AutoCodes.com — P20C0 2017 GMC Sierra Code - Reductant Heater 2 Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P20C0 2017 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 P20C0 2017 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 P20C0 2017 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 P20C0 2017 GMC Sierra code?

Need more information on how to fix the P20C0 2017 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P20C0 2017 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 P20C0 2017 GMC Sierra Code

1. What are the common symptoms of OBDII code P20C0 in a 2017 GMC Sierra?

- Common symptoms include the Check Engine light illuminating, reduced engine performance, and potential issues with the vehicle's emissions system.

2. What does the OBDII code P20C0 "Reductant Heater 2 Control Circuit High Voltage" indicate in a 2017 GMC Sierra?

- This code indicates that there is a high voltage condition detected in the control circuit for Reductant Heater 2 in the emissions system.

3. What are the possible causes of OBDII code P20C0 in a 2017 GMC Sierra?

- Possible causes include a faulty reductant heater, damaged wiring or connectors in the control circuit, a defective powertrain control module (PCM), or a software issue.

4. How can I diagnose the OBDII code P20C0 in my 2017 GMC Sierra?

- Diagnosing this code typically involves checking the reductant heater 2 circuit for proper voltage levels, inspecting wiring for damage, and testing the PCM for proper operation.

5. Can I continue driving my 2017 GMC Sierra with OBDII code P20C0 present?

- It is generally not recommended to continue driving the vehicle with this code present, as it can lead to decreased fuel efficiency and potential damage to the emissions system.

6. How can I repair OBDII code P20C0 in my 2017 GMC Sierra?

- Repairing this code may involve replacing the reductant heater 2, repairing damaged wiring or connectors, resetting the PCM, and clearing the error code from the system.

7. Is it possible to reset the OBDII code P20C0 in a 2017 GMC Sierra without making repairs?

- While you can reset the code using an OBDII scanner, it is crucial to address the underlying issue causing the code to prevent it from reoccurring.

8. Can extreme weather conditions cause OBDII code P20C0 to trigger in a 2017 GMC Sierra?

- Extreme temperatures can potentially impact the reductant heater's performance and lead to issues triggering this code, especially in very cold or hot conditions.

9. Will OBDII code P20C0 impact my 2017 GMC Sierra's emissions test results?

- Yes, this code can affect your vehicle's emissions, potentially causing it to fail an emissions test until the issue is resolved.

10. How long does it typically take to repair OBDII code P20C0 in a 2017 GMC Sierra?

- The repair time can vary based on the exact cause of the issue, but it may take a few hours to a full day to diagnose, repair, and clear the code from the system.