Engine-Codes.com
Engine-Codes – Subaru – P0158 Subaru

P0158 Subaru Code - HO2S22 Circuit High Voltage

Quick Answer

The P0158 code for a Subaru refers to the HO2S22 (Heated Oxygen Sensor 2 Bank 2) circuit registering a high voltage. Common causes include Faulty HO2S22 sensor, Damaged wiring or connectors, Vacuum leak. 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
P0158 Subaru indicates HO2S22 Circuit High Voltage.
Common causes
Common causes include Faulty HO2S22 sensor, Damaged wiring or connectors, Vacuum leak.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0158 Subaru Description

The P0158 code for a Subaru refers to the HO2S22 (Heated Oxygen Sensor 2 Bank 2) circuit registering a high voltage. This oxygen sensor is responsible for monitoring the oxygen levels in the exhaust gases to ensure the engine is running efficiently. When the voltage output from this sensor is higher than expected, it indicates a potential issue with the sensor or the circuit. This can lead to incorrect fuel mixture adjustments, affecting the engine's performance and emissions output.

OBDII Code P0158 Subaru - HO2S22 Circuit High Voltage
P0158 Subaru Code - HO2S22 Circuit High Voltage

Common Causes of P0158 Subaru

  1. Faulty HO2S22 sensor
  2. Damaged wiring or connectors
  3. Vacuum leak
  4. Exhaust leak
  5. Fuel system issues

Symptoms of P0158 Subaru

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Hesitation during acceleration
  4. Check Engine Light illuminated
  5. Higher emissions output

How to Fix P0158 Subaru

  1. Begin by inspecting the wiring and connectors leading to the HO2S22 sensor for any visible damage. Repair or replace any damaged components.
  2. Check for any vacuum leaks in the intake system and repair as necessary.
  3. Inspect the exhaust system for leaks that could be affecting the sensor's readings. Repair or replace any leaking components.
  4. Test the HO2S22 sensor using a multimeter to determine if it is functioning properly. Replace the sensor if it is found to be faulty.
  5. Clear the diagnostic trouble codes from the vehicle's PCM using an OBD-II scanner and drive the vehicle to verify that the issue has been resolved.

Cost to Fix P0158 Subaru

The cost of repairing a P0158 code on a Subaru can vary depending on the specific cause of the issue. On average, you can expect to pay between $200 and $500 for parts and labor. This estimate includes the cost of a new HO2S22 sensor, any necessary wiring repairs, and diagnostic time. Keep in mind that labor rates can vary between auto repair shops, so it's advisable to obtain quotes from multiple locations to ensure you are getting a fair price for the repair.

What does this mean?

Tech Notes for P0158 Subaru

Replacing the Rear Heated Oxygen Sensor Bank 2 usually takes care of the problem.

When is the Code Detected?

The P0158 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor signal voltage remains excessively high for an extended period of time.

Need more information about the P0158 Subaru code?

Need more information on how to fix the P0158 Subaru code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0158 Subaru code diagnosed by a professional: Find a repair shop in your area

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 P0158 Subaru Code

What does the OBDII code P0158 mean for a Subaru?

P0158 indicates that the voltage in the downstream oxygen sensor (HO2S22) of Bank 2 is higher than the expected range, suggesting a possible issue with the sensor or related components.

What are the common symptoms of code P0158 in a Subaru?

Symptoms may include poor fuel efficiency, rough idle, reduced engine performance, and the check engine light being illuminated.

What causes the P0158 code in a Subaru?

Common causes include a faulty oxygen sensor, shorted wiring or connections, exhaust leaks, or issues with the engine control module (ECM).

Can a faulty oxygen sensor trigger the P0158 code?

Yes, a failing downstream oxygen sensor (Bank 2, Sensor 2) is a primary cause of this code.

How do I diagnose the P0158 code on a Subaru?

Start by inspecting the oxygen sensor, wiring, and connectors for damage or corrosion, then use a multimeter to test the voltage readings.

Is it safe to drive with the P0158 code on my Subaru?

While it may be safe for short distances, prolonged driving can lead to poor engine performance and potential damage to other components.

How can I fix the P0158 code on a Subaru?

Repairs may include replacing the faulty oxygen sensor, repairing damaged wiring, or addressing exhaust system leaks.

Can an exhaust leak cause the P0158 code?

Yes, an exhaust leak near the oxygen sensor can create inaccurate readings and trigger the code.

Do I need to replace the ECU if I get the P0158 code?

Replacing the ECU is rare; most P0158 cases are resolved by fixing sensor or wiring issues.

How much does it cost to repair the P0158 code on a Subaru?

Costs can vary but typically range from $100 to $300 for sensor replacement, depending on labor rates and parts prices.

Discuss the causes and fixes for P0158 Subaru OBDII Code

Submit a New Comment

Code P0158 Subaru comments

No comments found for this page.