AutoCodes – Chevrolet – P21AB Chevrolet

P21AB Chevrolet Code - Reductant Level Sensor 2 Circuit High Voltage

Quick Answer

The reductant level/temperature sensor is a solid-state device that provides the Engine Control Module (ECM) with information on reductant level and temperature. Common causes include Faulty Reductant Level Sensor 2, Reductant Level Sensor 2 harness is open or shorted, Reductant Level Sensor 2 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: P21AB Chevrolet indicates Reductant Level Sensor 2 Circuit High Voltage.
Common causes: Common causes include Faulty Reductant Level Sensor 2, Reductant Level Sensor 2 harness is open or shorted, Reductant Level Sensor 2 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 1,608

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Sep 10, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P21AB Chevrolet Description

The reductant level/temperature sensor is a solid-state device that provides the Engine Control Module (ECM) with information on reductant level and temperature. The level/temperature sensor receives system voltage directly from the underhood electrical center and ground through a chassis ground circuit. The level sensor consists of three sensing elements. Reductant level sensor 3 is highest, reductant level sensor 2 is located between sensors 1 and 3. Reductant level sensor 1 is located at a low reductant level. Reductant level sensor 3 is located at less than half the range of the DEF tank level. The scan tool will display Active when the level sensors are in contact with the reductant and Inactive when not in contact with the reductant. An integrated temperature sensor monitors reductant temperature. Reductant level and temperature signals are processed within the sensor and supplied to the ECM as serial data messages. The ECM will set a DTC when it detects an invalid level or temperature serial data message from the sensor. The Diagnostic Trouble Code (DTC) will be set when the ECM receives a serial data message from the reductant sensor module that the emission reduction fluid tank level sensor 1, 2 or 3 voltage is between 3.56-4.74 V for greater than 3 s. A voltage within this range indicates an open circuit.

OBDII Code P21AB Chevrolet - Reductant Level Sensor 2 Circuit High Voltage - AutoCodes.com — P21AB Chevrolet Code - Reductant Level Sensor 2 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P21AB Chevrolet?

Faulty Reductant Level Sensor 2
Reductant Level Sensor 2 harness is open or shorted
Reductant Level Sensor 2 circuit poor electrical connection

How to Fix the DTC P21AB 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P21AB 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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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 P21AB Chevrolet Code

1. What are the common symptoms of OBDII code P21AB in a Chevrolet related to the Reductant Level Sensor 2 Circuit High Voltage?

- Common symptoms include the Check Engine light illuminated on the dashboard, reduced engine performance, and potential issues with the vehicle's emission system.

2. What are the possible causes of OBDII code P21AB in a Chevrolet indicating a Reductant Level Sensor 2 Circuit High Voltage?

- Possible causes include a faulty reductant level sensor, wiring or connector issues in the sensor circuit, or a malfunction in the engine control module.

3. How can I diagnose the OBDII code P21AB in a Chevrolet that points to a Reductant Level Sensor 2 Circuit High Voltage issue?

- Diagnosis involves using an OBDII scanner to retrieve the code, inspecting the reductant level sensor and its connections, and performing a voltage test to determine if the sensor is functioning properly.

4. Can driving with OBDII code P21AB in a Chevrolet due to a Reductant Level Sensor 2 Circuit High Voltage problem cause further damage to the vehicle?

- Continuing to drive with this code may cause increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter over time.

5. How can I repair OBDII code P21AB in a Chevrolet related to a Reductant Level Sensor 2 Circuit High Voltage issue?

- Repair options include replacing the faulty reductant level sensor, repairing any damaged wiring or connectors, or resetting the engine control module after addressing the underlying cause.

6. Is it safe to ignore OBDII code P21AB in a Chevrolet if the vehicle is still running fine?

- It is not recommended to ignore this code, as it can lead to increased emissions, potential environmental impact, and may cause the vehicle to fail emissions tests in some regions.

7. Can a DIY enthusiast fix OBDII code P21AB in a Chevrolet caused by a Reductant Level Sensor 2 Circuit High Voltage problem?

- Depending on the skill level and tools available, a DIY enthusiast may be able to address this issue by replacing the sensor, checking the wiring, and clearing the code with an OBDII scanner.

8. How much does it typically cost to repair OBDII code P21AB in a Chevrolet associated with a Reductant Level Sensor 2 Circuit High Voltage fault?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from $100 to $300 for parts and labor at a repair shop.

9. Are there any preventive maintenance measures to avoid OBDII code P21AB in a Chevrolet due to Reductant Level Sensor 2 Circuit High Voltage concerns?

- Regularly inspecting the emission system components, following recommended service intervals, and using high-quality diesel exhaust fluid (DEF) can help prevent issues with the reductant level sensor.

10. How long can I safely drive my Chevrolet with OBDII code P21AB related to a Reductant Level Sensor 2 Circuit High Voltage problem before getting it repaired?

- It is advisable to address the issue promptly to prevent potential damage to the emission system and ensure optimal performance. Driving with this code for an extended period is not recommended.