P1155 Subaru Code - HO2S21 Sensor Circuit Range/Performance High
Quick Answer
The P1155 code for Subaru vehicles specifically refers to a problem with the HO2S21 (Heated Oxygen Sensor 2 Bank 1 Sensor 1) sensor circuit, indicating that there is a range/performance issue detected. Common causes include Faulty HO2S21 sensor, Wiring or connector issues in the sensor circuit, Exhaust leaks near the sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1155 Subaru indicates HO2S21 Sensor Circuit Range/Performance High.
- Common causes
- Common causes include Faulty HO2S21 sensor, Wiring or connector issues in the sensor circuit, Exhaust leaks near the sensor.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P1155 Subaru Description
The P1155 code for Subaru vehicles specifically refers to a problem with the HO2S21 (Heated Oxygen Sensor 2 Bank 1 Sensor 1) sensor circuit, indicating that there is a range/performance issue detected. This sensor plays a crucial role in monitoring the oxygen levels in the exhaust gases, providing feedback to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion. When the sensor circuit is not performing within the expected range, it can lead to a variety of issues that can affect the vehicle's performance and emissions.
Common Causes of P1155 Subaru
- Faulty HO2S21 sensor.
- Wiring or connector issues in the sensor circuit.
- Exhaust leaks near the sensor.
- Engine running too lean or too rich.
- ECM malfunction.
Symptoms of P1155 Subaru
- Check Engine Light illuminated on the dashboard.
- Poor engine performance, including hesitation or rough idling.
- Reduced fuel efficiency.
- Vehicle stalling or difficulty starting.
- Increased emissions.
How to Fix P1155 Subaru
- Begin by diagnosing the root cause of the P1155 code by using a scan tool to read the code and determine the specific issue.
- Inspect the HO2S21 sensor and its wiring for any visible damage or corrosion. Replace the sensor if necessary.
- Check for any exhaust leaks near the sensor and repair as needed.
- Clear the code from the ECM memory and test drive the vehicle to ensure the issue has been resolved.
- If the problem persists, further diagnostics may be required to identify any underlying issues with the engine or ECM.
Cost to Fix P1155 Subaru
The cost estimate for repairing a P1155 code on a Subaru vehicle can vary depending on the specific cause of the issue. In general, replacing the HO2S21 sensor can cost between $100 to $200 for the part, with additional labor costs ranging from $100 to $200. Overall, the total repair cost can range from $200 to $400. It's important to note that labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more precise estimate based on your location and vehicle model.
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Frequently Asked Questions about P1155 Subaru Code
1. What does the OBDII code P1155 mean on a Subaru?
P1155 indicates an issue with the HO2S21 (Heated Oxygen Sensor Bank 2 Sensor 1) circuit, specifically a range/performance issue where the sensor's signal is outside its expected parameters.
2. What are the symptoms of a P1155 code on a Subaru?
Symptoms may include an illuminated Check Engine Light, reduced fuel efficiency, rough idling, poor engine performance, or hesitation during acceleration.
3. What causes the P1155 code on a Subaru?
Common causes include a faulty oxygen sensor, wiring issues (such as damaged or corroded connections), a malfunctioning engine control module (ECM), or exhaust leaks near the sensor.
4. How do I diagnose a P1155 code on my Subaru?
Start by inspecting the wiring and connectors for the Bank 2 Sensor 1 oxygen sensor. Use a scan tool to monitor live data and confirm if the sensor is functioning properly. Perform a resistance test on the sensor's heater circuit if necessary.
5. Can I drive my Subaru with a P1155 code?
While it may be possible to drive with this code, it’s not recommended long-term, as it can lead to decreased fuel efficiency, higher emissions, and potential damage to the catalytic converter.
6. How do I fix the P1155 code on my Subaru?
Repairs may include replacing the Bank 2 Sensor 1 oxygen sensor, repairing or replacing damaged wiring or connectors, fixing exhaust leaks, or updating/reprogramming the ECM if necessary.
7. Where is the HO2S21 sensor located on a Subaru?
The HO2S21 sensor (Bank 2 Sensor 1) is located on the exhaust manifold or pipe before the catalytic converter on the side of the engine opposite Cylinder 1.
8. How much does it cost to fix a P1155 code on a Subaru?
Repair costs can vary. Replacing the oxygen sensor typically costs between $100 and $300, depending on the part and labor rates. Wiring repairs or ECM updates may cost more.
9. Can a bad catalytic converter cause a P1155 code?
Yes, a failing catalytic converter can disrupt oxygen sensor readings and potentially trigger a P1155 code, though this is less common than sensor or wiring issues.
10. Will clearing the P1155 code fix the issue?
Clearing the code will temporarily remove it, but if the underlying issue isn’t addressed, the code will likely return after a short drive cycle.
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