AutoCodes – GMC – P0051 GMC

P0051 GMC Code - HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1

Quick Answer

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1, Heated Oxygen Sensor Bank 2 Sensor 1 harness is open shorted, Heated Oxygen Sensor Bank 2 Sensor 1 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0051 GMC indicates HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1.
Common causes: Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1, Heated Oxygen Sensor Bank 2 Sensor 1 harness is open shorted, Heated Oxygen Sensor Bank 2 Sensor 1 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 5,657

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 23, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0051 GMC Description

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach an operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensors to reach operating temperature. Voltage is provided to the heater by an ignition voltage circuit through a fuse. With the engine running, the ground is provided to the heater by the HO2S heater low control circuit through a low side driver within the Engine Control Module (ECM). The ECM uses Pulse Width Modulation (PWM) to control the HO2S heater operation to maintain a specific HO2S operating temperature range.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects a short to ground in the heater output low side driver circuit of the heated oxygen sensor when the heater is commanded OFF for greater than 5 s.

OBDII Code P0051 GMC - HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1 - AutoCodes.com — P0051 GMC Code - HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1

What does this mean?

What are the Possible Causes of the DTC P0051 GMC?

Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1
Heated Oxygen Sensor Bank 2 Sensor 1 harness is open shorted
Heated Oxygen Sensor Bank 2 Sensor 1 circuit poor electrical connection
Heated Oxygen Sensor Bank 2 Sensor 1 fuse
Faulty Engine Control Module (ECM)

How to Fix the DTC P0051 GMC?

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

The code means that there is a problem with the heater element circuit of the heated oxygen sensor. The control module monitors how long it takes the sensor to warm up and start sending an adequate signal. The code is set when the sensor is taking too long to warm up. Water getting inside the heated oxygen sensor connector can cause the heated oxygen sensor fuse to blow. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors. If the fuse and connector are OK, replacing the O2 Sensor usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0051 GMC 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 GMC Models

P0051 2014 GMC Sierra — HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1
P0051 2015 GMC Sierra — HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1
P0051 2016 GMC Sierra — HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1
P0051 2017 GMC Sierra — HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1
P0051 2018 GMC Sierra — HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1

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 P0051 GMC Code

1. What are common symptoms of OBDII code P0051 GMC?

- Common symptoms include poor fuel economy, rough idling, decreased engine performance, and the illumination of the check engine light.

2. What does the OBDII code P0051 GMC indicate?

- This code indicates a low voltage condition in the heater control circuit of the oxygen sensor (HO2S) for Bank 2 Sensor 1.

3. What are possible causes of OBDII code P0051 GMC?

- Possible causes include a faulty oxygen sensor, damaged wiring or connectors in the sensor circuit, a blown fuse, or a problem with the engine control module (ECM).

4. How can I diagnose the cause of OBDII code P0051 GMC?

- Diagnose the code by inspecting the sensor wiring and connectors, testing the sensor's resistance, checking the fuse related to the sensor circuit, and using a scan tool to monitor sensor data.

5. Can I continue driving with OBDII code P0051 GMC?

- It is not recommended to continue driving with this code as it can lead to reduced engine performance and potential damage to the catalytic converter over time.

6. How can I repair OBDII code P0051 GMC?

- Repair options include replacing the oxygen sensor, repairing damaged wiring or connectors, replacing a blown fuse, or reprogramming the ECM if necessary.

7. Is it necessary to replace the oxygen sensor for OBDII code P0051 GMC?

- In many cases, replacing the oxygen sensor is the most effective solution for resolving the low voltage issue in the heater control circuit.

8. How much does it cost to fix OBDII code P0051 GMC?

- The cost of fixing this code can vary depending on the specific issue, but it typically ranges from $200 to $500 for parts and labor.

9. Can I clear OBDII code P0051 GMC without fixing the issue?

- Clearing the code without addressing the underlying problem will only temporarily turn off the check engine light, and the issue will likely reoccur.

10. How long does it take to repair OBDII code P0051 GMC?

- The repair time can vary based on the exact cause of the code, but it typically takes 1-2 hours for a professional mechanic to diagnose and fix the issue.