AutoCodes – Subaru – P0152 Subaru

P0152 Subaru Code - HO2S21 Circuit High Voltage

Quick Answer

The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold. Common causes include Faulty Front Heated Oxygen Sensor Bank 2, Intake air leaks may be faulty, Exhaust gas leaks. 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: P0152 Subaru indicates HO2S21 Circuit High Voltage.
Common causes: Common causes include Faulty Front Heated Oxygen Sensor Bank 2, Intake air leaks may be faulty, Exhaust gas leaks.
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 5,400

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 Jun 14, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0152 Subaru Description

The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the Engine Control Module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.

OBDII Code P0152 Subaru - HO2S21 Circuit High Voltage - AutoCodes.com — P0152 Subaru Code - HO2S21 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0152 Subaru?

Faulty Front Heated Oxygen Sensor Bank 2
Intake air leaks may be faulty
Exhaust gas leaks
Front Heated Oxygen Sensor Bank 2 harness is open or shorted
Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors

How to Fix the DTC P0152 Subaru?

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 Bank 2 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0152 Subaru 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 P0152 Subaru Code

1. What are common symptoms of OBDII code P0152 in a Subaru related to HO2S21 Circuit High Voltage?

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

2. What does the HO2S21 Circuit High Voltage code P0152 in a Subaru indicate?

- The code indicates that the oxygen sensor (HO2S) located after the catalytic converter on bank 2 is sending a high voltage signal to the engine control module.

3. What are potential causes of OBDII code P0152 in a Subaru?

- Possible causes include a faulty oxygen sensor (HO2S), wiring or connector issues in the HO2S21 circuit, exhaust leaks, or a malfunctioning engine control module.

4. How can I diagnose the HO2S21 Circuit High Voltage code P0152 in my Subaru?

- Diagnosing the issue involves inspecting the HO2S21 sensor, checking the wiring and connectors for damage, scanning for additional trouble codes, and performing voltage tests.

5. Can I drive my Subaru with the OBDII code P0152 related to HO2S21 Circuit High Voltage?

- It is not recommended to drive the vehicle for an extended period with this code, as it can lead to further engine damage and decreased fuel efficiency.

6. How can I repair OBDII code P0152 in my Subaru myself?

- DIY repair options include replacing the HO2S21 sensor, repairing any damaged wiring or connectors, and clearing the trouble code using an OBDII scanner.

7. Is it necessary to replace the HO2S21 sensor when dealing with code P0152 in a Subaru?

- In most cases, replacing the faulty HO2S21 sensor is the most effective solution to resolve the high voltage issue and clear the trouble code.

8. How much does it cost to fix OBDII code P0152 related to HO2S21 Circuit High Voltage in a Subaru?

- The cost of repair can vary depending on the root cause of the issue, but it typically ranges from $100 to $300 for parts and labor.

9. Can a Subaru dealership or mechanic reset the Check Engine Light after fixing code P0152 HO2S21 Circuit High Voltage?

- Yes, a dealership or mechanic can use an OBDII scanner to reset the Check Engine Light after repairing the issue and clearing the trouble code.

10. What steps should I take if the OBDII code P0152 in my Subaru keeps coming back after repairs?

- If the code persists after repairs, it is recommended to recheck the sensor, wiring, and connectors for any issues, or consult a professional for further diagnosis.