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Engine-Codes – Ford – P0139 2008 Ford Fusion

P0139 2008 Ford Fusion Code - O2 Sensor Circuit Slow Response Bank 1 Sensor 2

Quick Answer

The P0139 code for a 2008 Ford Fusion indicates a problem with the O2 sensor circuit's slow response in Bank 1 Sensor 2. Common causes include Faulty O2 sensor, Wiring or connector issues in the O2 sensor circuit, Contaminated sensor due to oil or coolant leaks. 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 2008 Ford Fusion indicates O2 Sensor Circuit Slow Response Bank 1 Sensor 2.
Common causes
Common causes include Faulty O2 sensor, Wiring or connector issues in the O2 sensor circuit, Contaminated sensor due to oil or coolant leaks.
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 17, 2024
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Code P0139 2008 Ford Fusion Description

The P0139 code for a 2008 Ford Fusion indicates a problem with the O2 sensor circuit's slow response in Bank 1 Sensor 2. The O2 sensor, also known as the oxygen sensor, plays a crucial role in monitoring the oxygen levels in the exhaust gases. This specific sensor, located after the catalytic converter in Bank 1 (which typically refers to the side of the engine with cylinder 1), is responsible for measuring the oxygen content in the exhaust gases to ensure the proper air-fuel ratio for optimal engine performance and emissions control.

OBDII Code P0139 2008 Ford Fusion - O2 Sensor Circuit Slow Response Bank 1 Sensor 2
P0139 2008 Ford Fusion Code - O2 Sensor Circuit Slow Response Bank 1 Sensor 2

Common Causes of P0139 2008 Ford Fusion

  1. Faulty O2 sensor
  2. Wiring or connector issues in the O2 sensor circuit
  3. Contaminated sensor due to oil or coolant leaks
  4. Exhaust leaks near the sensor
  5. ECM malfunction

Symptoms of P0139 2008 Ford Fusion

  1. Decreased fuel efficiency
  2. Engine misfires or rough idling
  3. Check Engine Light illuminated
  4. Poor acceleration or hesitation
  5. Increased emissions

How to Fix P0139 2008 Ford Fusion

  1. Begin by diagnosing the specific cause of the slow response in the O2 sensor circuit using a scan tool to read live data and pinpoint the issue.
  2. Inspect the wiring and connectors for any damage or corrosion, repairing or replacing as necessary.
  3. Test the O2 sensor itself for proper function and replace if found to be faulty.
  4. Clear the diagnostic trouble codes from the ECM and perform a test drive to ensure the issue has been resolved.
  5. If the problem persists, further diagnostics may be needed to identify any underlying issues with the ECM or other components.

Cost to Fix P0139 2008 Ford Fusion

The typical repair costs for addressing a P0139 code on a 2008 Ford Fusion can range from $150 to $400, depending on the specific cause of the issue and the cost of parts and labor. It's important to note that diagnostic time and labor rates at auto repair shops can vary, with hourly rates typically ranging from $80 to $150. Factors such as location, vehicle make and model, and engine type can also influence the final repair costs. It's recommended to obtain quotes from local auto repair shops for a more accurate estimate.

What does this mean?

Tech Notes for P0139 2008 Ford Fusion

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

When is the Code Detected?

The P0139 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor takes more time to respond between rich and lean than the specified time.

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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 2008 Ford Fusion Code

1. What are the common symptoms of OBDII code P0139 on a 2008 Ford Fusion?

- Common symptoms include a check engine light illuminated on the dashboard, poor fuel economy, rough idling, and decreased engine performance.

2. What does the OBDII code P0139 "O2 Sensor Circuit Slow Response Bank 1 Sensor 2" mean on a 2008 Ford Fusion?

- This code indicates that the oxygen sensor located downstream of the catalytic converter on Bank 1 is responding slowly or intermittently.

3. What are the possible causes of OBDII code P0139 on a 2008 Ford Fusion?

- Possible causes include a faulty oxygen sensor, wiring issues in the O2 sensor circuit, exhaust leaks, or a malfunctioning catalytic converter.

4. How can I diagnose the O2 sensor circuit slow response issue on my 2008 Ford Fusion?

- Diagnose by visually inspecting the O2 sensor and its wiring for damage, checking for exhaust leaks, testing the sensor's voltage output, and using a scan tool to monitor sensor data.

5. Can I drive my 2008 Ford Fusion with the OBDII code P0139 without repairing it immediately?

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

6. How do I repair the O2 sensor circuit slow response issue on my 2008 Ford Fusion?

- Repair options include replacing the Bank 1 Sensor 2 oxygen sensor, repairing any damaged wiring, fixing exhaust leaks, or replacing the catalytic converter if necessary.

7. Will resetting the OBDII code P0139 on my 2008 Ford Fusion make it go away permanently?

- Resetting the code may temporarily turn off the check engine light, but if the underlying issue is not fixed, the code is likely to return after driving the vehicle for a while.

8. How much does it typically cost to repair the O2 sensor circuit slow response issue on a 2008 Ford Fusion?

- The cost of repairs can vary depending on the specific cause, but replacing the oxygen sensor or repairing wiring issues may range from $150 to $400, while replacing the catalytic converter can cost more.

9. Can a DIY enthusiast fix the OBDII code P0139 issue on a 2008 Ford Fusion?

- DIY enthusiasts with the right tools and knowledge can potentially diagnose and replace the oxygen sensor or repair wiring issues themselves, but more complex repairs may require professional assistance.

10. How often should the oxygen sensors be replaced on a 2008 Ford Fusion to prevent O2 sensor circuit slow response issues?

- Oxygen sensors typically last around 60,000 to 100,000 miles, so it's recommended to replace them within this mileage range to avoid issues like slow response and decreased fuel efficiency.

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