AutoCodes – Scion – P0139 2005 Scion xB

P0139 2005 Scion xB Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2

Quick Answer

The rear Heated Oxygen (HO2) sensor (bank 1 sensor 2) is located behind the Three-Way Catalytic Converter (TWC) and detects the oxygen concentration in the exhaust gas. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 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: P0139 2005 Scion xB indicates Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2.
Common causes: Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 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 2,850

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 Mar 14, 2021

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0139 2005 Scion xB Description

The rear Heated Oxygen (HO2) sensor (bank 1 sensor 2) is located behind the Three-Way Catalytic Converter (TWC) and detects the oxygen concentration in the exhaust gas. For optimum TWC operation, the air-fuel mixture must be maintained as close as possible to the stoichiometric ratio. The HO2 sensor output voltage changes dramatically in the vicinity of the stoichiometric ratio. By making adjustments in accordance with these signal voltage changes, the ECM adjusts the fuel injection time so that the air-fuel ratio remains as close as possible to stoichiometric levels. The rear HO2 sensor generates a voltage that ranges from 0.1 V to 0.9 V according to the oxygen concentration in the exhaust gas. When the oxygen concentration in the exhaust gas increases, the HO2 sensor voltage drops below 0.45 V. The ECM interprets this as the air-fuel ratio is lean. Alternatively, the sensor voltage rises to more than 0.45 V when there is no oxygen in the exhaust gas. The ECM interprets this as the air-fuel ratio is rich.

OBDII Code P0139 2005 Scion xB - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2 - AutoCodes.com — P0139 2005 Scion xB Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0139 2005 Scion xB?

Faulty Rear Heated Oxygen Sensor Bank 1
Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

How to Fix the DTC P0139 2005 Scion xB?

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 Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0139 2005 Scion xB 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 P0139 2005 Scion xB Code

1. What are the common symptoms of OBDII code P0139 on a 2005 Scion xB?

- Common symptoms may include poor fuel efficiency, rough idling, and an illuminated check engine light.

2. What does the OBDII code P0139 for a 2005 Scion xB indicate?

- The code signifies an Oxygen Sensor Circuit Slow Response for Bank 1 Sensor 2, indicating a delayed response from the downstream oxygen sensor.

3. What are the possible causes of OBDII code P0139 on a 2005 Scion xB?

- Causes may include a faulty downstream oxygen sensor, wiring issues, exhaust leaks, or a malfunctioning catalytic converter.

4. How can I diagnose the issue related to OBDII code P0139 on my 2005 Scion xB?

- Diagnosis involves inspecting the downstream oxygen sensor and related wiring, checking for exhaust leaks, and testing the functionality of the catalytic converter.

5. What are the repair options for addressing OBDII code P0139 on a 2005 Scion xB?

- Repair options may include replacing the downstream oxygen sensor, repairing wiring issues, fixing exhaust leaks, or replacing the catalytic converter if necessary.

6. Can I drive my 2005 Scion xB with the OBDII code P0139 illuminated?

- It is not recommended to drive for an extended period with the code active, as it can lead to reduced fuel efficiency and potential damage to the catalytic converter.

7. How much does it cost to repair OBDII code P0139 on a 2005 Scion xB?

- The cost of repair can vary depending on the specific issue, but it may range from $100 to $500 or more, including parts and labor.

8. Will resetting the check engine light resolve OBDII code P0139 on my 2005 Scion xB?

- Resetting the light may temporarily turn it off, but the underlying issue causing the code will persist until repaired, causing the light to illuminate again.

9. How often should I replace the oxygen sensors on a 2005 Scion xB to prevent OBDII code P0139?

- Oxygen sensors typically have a lifespan of 60,000 to 90,000 miles, so it is recommended to replace them within this mileage range to prevent issues like code P0139.

10. Is it safe to ignore OBDII code P0139 on a 2005 Scion xB if the vehicle seems to be running fine?

- Ignoring the code can lead to decreased fuel efficiency and potential damage to the catalytic converter over time, so it is advisable to address the issue promptly.