AutoCodes – Subaru – P0153 Subaru

P0153 Subaru Code - HO2S21 Circuit Slow Response

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, 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: P0153 Subaru indicates HO2S21 Circuit Slow Response.
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 5,182

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 P0153 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 P0153 Subaru - HO2S21 Circuit Slow Response - AutoCodes.com — P0153 Subaru Code - HO2S21 Circuit Slow Response

What does this mean?

What are the Possible Causes of the DTC P0153 Subaru?

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
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks
Exhaust gas leaks

How to Fix the DTC P0153 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 P0153 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 P0153 Subaru Code

1. What does the OBDII code P0153 mean on a Subaru?

The code P0153 indicates that the Bank 2, Sensor 1 oxygen sensor (HO2S21) is responding too slowly to changes in exhaust gas levels.

2. What are the symptoms of P0153 in a Subaru?

Symptoms may include reduced fuel efficiency, rough idling, engine misfires, increased emissions, or the Check Engine Light turning on.

3. What causes the P0153 code to appear in a Subaru?

Common causes include a faulty oxygen sensor, exhaust leaks, wiring issues, a dirty sensor, or an engine running too rich or too lean.

4. Can a dirty oxygen sensor trigger the P0153 code?

Yes, a dirty or contaminated oxygen sensor can cause slow response times, leading to the P0153 code.

5. How do I fix the P0153 code on my Subaru?

Repairs may involve cleaning or replacing the oxygen sensor, checking for exhaust leaks, inspecting wiring and connectors, and ensuring proper air-fuel mixture.

6. Is it safe to drive with the P0153 code on a Subaru?

While the vehicle may still function, driving with this code can lead to reduced fuel efficiency and potential damage to the catalytic converter over time.

7. How can I test the oxygen sensor for the P0153 code?

You can use a multimeter or an OBDII scanner to monitor the sensorâ€™s voltage readings and response time to ensure it is functioning correctly.

8. Can a vacuum leak cause the P0153 code in a Subaru?

Yes, vacuum leaks can disrupt the air-fuel mixture, leading to slow oxygen sensor response and triggering the P0153 code.

9. How much does it cost to fix the P0153 code on a Subaru?

Repair costs vary but typically range from $100 to $300, depending on whether the oxygen sensor needs replacement or other components require attention.

10. What tools do I need to diagnose the P0153 code on a Subaru?

Youâ€™ll need an OBDII scanner, multimeter, and possibly hand tools for inspecting and replacing the oxygen sensor or related components.