AutoCodes – Subaru – P1139 Subaru

P1139 Subaru Code - Front Oxygen A/F Sensor #1 Heater Circuit Performance/Range Problem

Quick Answer

P1139 Subaru indicates Front Oxygen A/F Sensor #1 Heater Circuit Performance/Range Problem. Common causes include Faulty Front Oxygen A/F Sensor 11, Front Oxygen A/F Sensor 11 harness is open or shorted, Front Oxygen A/F Sensor 11 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: P1139 Subaru indicates Front Oxygen A/F Sensor #1 Heater Circuit Performance/Range Problem.
Common causes: Common causes include Faulty Front Oxygen A/F Sensor 11, Front Oxygen A/F Sensor 11 harness is open or shorted, Front Oxygen A/F Sensor 11 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.

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Code Popularity 13,803

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 30, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1139 Subaru Description

OBDII Code P1139 Subaru - Front Oxygen A/F Sensor #1 Heater Circuit Performance/Range Problem - AutoCodes.com — P1139 Subaru Code - Front Oxygen A/F Sensor #1 Heater Circuit Performance/Range Problem

What does this mean?

What are the Possible Causes of the DTC P1139 Subaru?

Faulty Front Oxygen A/F Sensor 11
Front Oxygen A/F Sensor 11 harness is open or shorted
Front Oxygen A/F Sensor 11 circuit poor electrical connection

How to Fix the DTC P1139 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 P1139 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.

Need more information about the P1139 Subaru code?

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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 P1139 Subaru Code

1. What are the common symptoms of OBDII code P1139 in a Subaru?

- Common symptoms include poor fuel efficiency, rough idle, engine hesitation, and potentially a noticeable decrease in overall engine performance.

2. What typically causes the OBDII code P1139 in a Subaru?

- This code is often triggered by a malfunction in the Front Oxygen A/F Sensor #1 Heater circuit, which can be caused by a faulty sensor, wiring issues, or a problem with the sensor heater circuit.

3. How serious is the OBDII code P1139 in a Subaru?

- While this code may not cause immediate engine failure, it can lead to decreased fuel efficiency and potential long-term damage to the engine if not addressed promptly.

4. Can I continue driving my Subaru with the OBDII code P1139 present?

- It is not recommended to drive your Subaru with this code present, as it can lead to poor engine performance and potentially cause further damage over time.

5. How can I diagnose the OBDII code P1139 in my Subaru?

- Diagnosing this code typically involves using an OBDII scanner to retrieve the code and then further testing the Front Oxygen A/F Sensor #1 and its related components for faults.

6. How can I repair the OBDII code P1139 in my Subaru?

- Repairing this code usually involves replacing the Front Oxygen A/F Sensor #1 if it is found to be faulty, checking and repairing any damaged wiring, or addressing issues with the sensor heater circuit.

7. Are there any DIY tips for fixing the OBDII code P1139 in a Subaru?

- While some enthusiasts may attempt to replace the Front Oxygen A/F Sensor #1 themselves, it is recommended to have this repair done by a qualified mechanic to ensure proper installation and functioning.

8. Can resetting the OBDII code P1139 in my Subaru resolve the issue?

- Resetting the code may temporarily turn off the Check Engine Light, but if the underlying issue causing the code is not addressed, it is likely to return.

9. How much does it typically cost to repair the OBDII code P1139 in a Subaru?

- The cost of repairing this code can vary depending on the root cause of the issue, but it may range from $200 to $500 including parts and labor.

10. How often does the OBDII code P1139 occur in Subaru vehicles?

- This code can occur sporadically in Subaru vehicles, especially in older models or those with high mileage, due to wear and tear on the sensor and its components.