P1155 Subaru Code - HO2S21 Sensor Circuit Range/Performance High
Quick Answer
P1155 Subaru indicates HO2S21 Sensor Circuit Range/Performance High. Common causes include Faulty O2 Sensor HO2S21, O2 Sensor HO2S21 harness is open or shorted, O2 Sensor HO2S21 circuit poor electrical connection. 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 O2 Sensor HO2S21, O2 Sensor HO2S21 harness is open or shorted, O2 Sensor HO2S21 circuit poor electrical connection.
- 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.
Code P1155 Subaru Description
What are the Possible Causes of the DTC P1155 Subaru?
- Faulty O2 Sensor HO2S21
- O2 Sensor HO2S21 harness is open or shorted
- O2 Sensor HO2S21 circuit poor electrical connection
How to Fix the DTC P1155 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 is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1155 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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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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