AutoCodes – Generic – P0151

P0151 Code - O2 Sensor Circuit Low Voltage Bank 2 Sensor 1

Quick Answer

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Common causes include Faulty Front Heated Oxygen Sensor Bank 2, Front Heated Oxygen Sensor Bank 2 harness is open or shorted, Front Heated Oxygen Sensor Bank 2 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: P0151 indicates O2 Sensor Circuit Low Voltage Bank 2 Sensor 1.
Common causes: Common causes include Faulty Front Heated Oxygen Sensor Bank 2, Front Heated Oxygen Sensor Bank 2 harness is open or shorted, Front Heated Oxygen Sensor Bank 2 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 50,385

How popular is this code, among other codes? Medium

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 May 27, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0151 Description

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the Engine Control Module (ECM) operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0 - 1, 000 mV. Once sufficient HO2S voltage fluctuation is observed by the ECM, Closed Loop is entered. The ECM uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the ECM to calculate the air-to-fuel ratio sooner.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the heated oxygen sensor is shorted to ground if the HO2S voltage is less than 50 mV.

OBDII Code P0151 - O2 Sensor Circuit Low Voltage Bank 2 Sensor 1 - AutoCodes.com — P0151 Code - O2 Sensor Circuit Low Voltage Bank 2 Sensor 1

What does this mean?

What are the Possible Causes of the DTC P0151?

Faulty Front Heated Oxygen Sensor Bank 2
Front Heated Oxygen Sensor Bank 2 harness is open or shorted
Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection
Low or high fuel system pressure
Fuel contamination
Faulty fuel injectors
Exhaust gas leaks
Engine vacuum leaks

How to Fix the DTC P0151?

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

Replacing the Front Heated Oxygen Sensor (HO2S) Bank 2 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0151 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 Makes

P0151 Audi — HO2S21 Sensor Circuit Low Voltage
P0151 BMW — O2 Sensor Circuit Low Voltage Bank 2 Sensor 1
P0151 Buick — HO2S Circuit Low Voltage Bank 2 Sensor 1
P0151 Cadillac — HO2S Circuit Low Voltage Bank 2 Sensor 1
P0151 Chevrolet — HO2S Circuit Low Voltage Bank 2 Sensor 1
P0151 Chrysler — O2 sensor 2/1 Circuit Low
P0151 Dodge — O2 sensor 2/1 Circuit Low
P0151 Ford — O2 Sensor Circuit Low Voltage Bank 2 Sensor 1
P0151 GMC — HO2S Circuit Low Voltage Bank 2 Sensor 1
P0151 Hyundai — HO2S Circuit Low Voltage Bank 2 Sensor 1
P0151 Infiniti — Air Fuel Ratio Circuit Low Bank 2 Sensor 1
P0151 Infiniti — O2 Sensor Circuit Low Bank 2 Sensor 1
P0151 Jaguar — O2 Sensor Circuit Low Voltage Bank 2 Sensor 1
P0151 Jeep — O2 sensor 2/1 Circuit Low
P0151 KIA — HO2S21 Circuit Low Voltage
P0151 Mazda — HO2S LF Circuit Low Input
P0151 Mercedes-Benz — O2 Sensor Circuit Low Voltage Bank 2 Sensor 1
P0151 MINI — O2 Sensor Circuit Low Voltage Bank 2 Sensor 1
P0151 Mitsubishi — Cylinder 2-3 Front Heated Oxygen Sensor Circuit Low Voltage
P0151 Nissan — Air Fuel Ratio Circuit Low Bank 2 Sensor 1
P0151 Nissan — O2 Sensor Circuit Low Bank 2 Sensor 1
P0151 Pontiac — HO2S Circuit Low Voltage Bank 2 Sensor 1
P0151 Saturn — HO2S Circuit Low Voltage Bank 2 Sensor 1
P0151 Subaru — HO2S21 Circuit Low Voltage
P0151 Toyota — O2 Sensor Circuit Low Voltage Bank 2 Sensor 1
P0151 Volkswagen — HO2S21 Sensor 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 P0151 Code

1. What are the common symptoms of OBDII code P0151 (O2 Sensor Circuit Low Voltage Bank 2 Sensor 1)?

- Common symptoms include poor fuel economy, rough idling, and a noticeable decrease in engine performance.

2. What are the possible causes of OBDII code P0151?

- Possible causes include a faulty oxygen sensor, damaged wiring or connectors in the O2 sensor circuit, or an exhaust leak near the sensor.

3. How can I diagnose the O2 Sensor Circuit Low Voltage Bank 2 Sensor 1 issue?

- Diagnose the issue by using an OBDII scanner to read the specific trouble code, visually inspecting the sensor and its wiring, and performing voltage tests on the sensor.

4. Can a dirty or contaminated oxygen sensor cause code P0151?

- Yes, a dirty or contaminated oxygen sensor can cause code P0151 by affecting the sensor's ability to accurately measure oxygen levels in the exhaust.

5. What are some repair tips for addressing OBDII code P0151?

- Repair tips include cleaning the sensor, checking and repairing any damaged wiring, ensuring proper sensor installation, and replacing the oxygen sensor if necessary.

6. Is it safe to continue driving with OBDII code P0151 present?

- It is not recommended to continue driving with code P0151 as it can lead to further engine damage and decreased fuel efficiency if left unresolved.

7. Can a faulty catalytic converter trigger OBDII code P0151?

- Yes, a faulty catalytic converter can trigger code P0151 as it can affect the oxygen sensor's readings and cause the sensor to detect low voltage.

8. How important is it to address OBDII code P0151 promptly?

- It is important to address code P0151 promptly to prevent potential damage to the engine, reduce emissions, and maintain optimal fuel efficiency.

9. Are there any DIY repairs for O2 Sensor Circuit Low Voltage Bank 2 Sensor 1 issues?

- DIY repairs may include cleaning the sensor, checking and repairing wiring connections, and replacing the oxygen sensor with the proper tools and knowledge.

10. How much does it typically cost to repair OBDII code P0151?

- The cost of repairing code P0151 can vary depending on the cause of the issue, but it may range from $100 to $400 for parts and labor.

1. What does OBDII code P0151 mean?

- OBDII code P0151 indicates a low voltage condition in the O2 sensor circuit of Bank 2 Sensor 1.

2. What are the common symptoms of OBDII code P0151?

- Common symptoms of P0151 include poor fuel economy, rough idling, engine misfires, and the illumination of the Check Engine Light.

3. What are the possible causes of OBDII code P0151?

- Possible causes of P0151 include a faulty O2 sensor, damaged wiring or connectors in the O2 sensor circuit, exhaust leaks, or issues with the engine's air-fuel mixture.

4. How can I diagnose OBDII code P0151?

- To diagnose P0151, you can use an OBDII scanner to read the fault code, visually inspect the O2 sensor and its wiring, and perform voltage and resistance tests on the sensor.

5. Can I continue driving with OBDII code P0151?

- While it may be possible to continue driving with P0151, it is recommended to address the issue promptly to prevent potential damage to the catalytic converter and ensure optimal engine performance.

6. Is it safe to clear the OBDII code P0151 without fixing the underlying issue?

- Clearing the P0151 code without addressing the root cause may temporarily turn off the Check Engine Light, but the issue will likely reoccur, leading to potential engine performance problems.

7. How do I repair OBDII code P0151?

- Repairing P0151 involves identifying and fixing the underlying issue, which may include replacing the faulty O2 sensor, repairing damaged wiring, fixing exhaust leaks, or addressing air-fuel mixture problems.

8. Can a DIY enthusiast fix OBDII code P0151?

- Depending on their skill level and access to tools, a DIY enthusiast may be able to fix P0151 by following repair guides and utilizing basic automotive repair knowledge.

9. How much does it cost to repair OBDII code P0151 at a professional auto repair shop?

- The cost of repairing P0151 at a professional auto repair shop can vary depending on the specific issue, but it may range from $100 to $300 or more, including parts and labor.

10. Are there any preventative measures to avoid OBDII code P0151 in the future?

- To prevent OBDII code P0151, it is essential to perform regular vehicle maintenance, such as replacing O2 sensors as recommended by the manufacturer, keeping the engine properly tuned, and addressing any engine performance issues promptly.