AutoCodes – Chevrolet – P20BB Chevrolet

P20BB Chevrolet Code - Reductant Heater 1 Control Circuit Low 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: P20BB Chevrolet indicates Reductant Heater 1 Control Circuit Low 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.

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Code Popularity 6,403

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
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P20BB Chevrolet 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 shorted to ground or overloaded for greater than 4 s.

OBDII Code P20BB Chevrolet - Reductant Heater 1 Control Circuit Low Voltage - AutoCodes.com — P20BB Chevrolet Code - Reductant Heater 1 Control Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P20BB Chevrolet?

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 P20BB Chevrolet?

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 does this mean?

Code Tech Notes

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P20BB Chevrolet 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.

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Information for Specific Chevrolet Models

P20BB 2014 Chevrolet Silverado — Reductant Heater 1 Control Circuit Low Voltage
P20BB 2015 Chevrolet Silverado — Reductant Heater 1 Control Circuit Low Voltage
P20BB 2016 Chevrolet Silverado — Reductant Heater 1 Control Circuit Low Voltage
P20BB 2017 Chevrolet Silverado — Reductant Heater 1 Control Circuit Low Voltage
P20BB 2018 Chevrolet Silverado — Reductant Heater 1 Control Circuit Low Voltage

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 P20BB Chevrolet Code

1. What are the common symptoms of OBDII code P20BB in a Chevrolet related to the Reductant Heater 1 Control Circuit Low Voltage?

The common symptoms include the check engine light illuminating on the dashboard, decreased engine performance, and potential issues with the vehicle's emissions system.

2. What are the possible causes of OBDII code P20BB in a Chevrolet indicating a Reductant Heater 1 Control Circuit Low Voltage?

Potential causes of this code include a faulty reductant heater 1, damaged wiring or connectors in the control circuit, a malfunctioning powertrain control module (PCM), or issues with the reductant heater control module.

3. How can I diagnose OBDII code P20BB in my Chevrolet related to the Reductant Heater 1 Control Circuit Low Voltage?

Diagnosing this code usually involves using an OBDII scanner to retrieve the specific fault code, inspecting the reductant heater and its wiring for any visible damage, and testing the circuit components for proper voltage and continuity.

4. Can I continue to drive my Chevrolet with OBDII code P20BB indicating a Reductant Heater 1 Control Circuit Low Voltage?

It is not recommended to continue driving the vehicle with this code present, as it can lead to increased emissions, reduced fuel efficiency, and potential damage to the engine or emissions system. It is best to address the issue promptly.

5. How do I repair OBDII code P20BB in my Chevrolet related to the Reductant Heater 1 Control Circuit Low Voltage?

Repairing this code typically involves replacing the faulty reductant heater 1, repairing or replacing damaged wiring or connectors, resetting the fault codes, and retesting the system to ensure the issue has been resolved.

6. Are there any specific maintenance tips to prevent OBDII code P20BB in a Chevrolet related to the Reductant Heater 1 Control Circuit Low Voltage?

Regularly inspecting the emissions system components, such as the reductant heater and its wiring, as part of routine maintenance can help prevent issues that may trigger this fault code.

7. Can a DIY enthusiast without advanced automotive knowledge fix OBDII code P20BB in a Chevrolet indicating a Reductant Heater 1 Control Circuit Low Voltage?

While some basic automotive knowledge is required, a DIY enthusiast with the right tools and resources can potentially address this code by following repair guides and tutorials specific to their Chevrolet model.

8. How much does it typically cost to repair OBDII code P20BB in a Chevrolet related to the Reductant Heater 1 Control Circuit Low Voltage?

The cost of repairing this code can vary depending on the root cause of the issue, the required parts, and whether the repair is done at a dealership or by an independent mechanic. Costs may range from a few hundred to over a thousand dollars.

9. Will resetting the check engine light resolve OBDII code P20BB in a Chevrolet indicating a Reductant Heater 1 Control Circuit Low Voltage?

Simply resetting the check engine light without addressing the underlying issue will not resolve the problem. It is essential to diagnose the cause of the fault code and perform the necessary repairs to prevent it from reoccurring.

10. How urgent is it to address OBDII code P20BB in a Chevrolet related to the Reductant Heater 1 Control Circuit Low Voltage?

It is recommended to address this code promptly to prevent potential damage to the emissions system and ensure optimal engine performance. Ignoring the issue can lead to increased emissions, reduced fuel efficiency, and possible engine problems over time.