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P0139 Toyota Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2

Quick Answer

The P0139 code for Toyota vehicles indicates a problem with the oxygen sensor circuit for Bank 1 Sensor 2, which is the sensor located downstream from the catalytic converter. Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor. 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 Toyota indicates Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2.
Common causes
Common causes include Faulty oxygen sensor, Wiring or connector issues, Exhaust leaks near the sensor.
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 Aug 30, 2024
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Code P0139 Toyota Description

The P0139 code for Toyota vehicles indicates a problem with the oxygen sensor circuit for Bank 1 Sensor 2, which is the sensor located downstream from the catalytic converter. This sensor is responsible for monitoring the oxygen levels in the exhaust gases to ensure optimal fuel efficiency and emissions control. A slow response from this sensor can lead to inaccurate readings being sent to the engine control module, which can negatively impact the vehicle's performance and fuel economy. If left unresolved, this issue can also cause damage to the catalytic converter and other engine components.

OBDII Code P0139 Toyota - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2
P0139 Toyota Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2

Common Causes of P0139 Toyota

  1. Faulty oxygen sensor
  2. Wiring or connector issues
  3. Exhaust leaks near the sensor
  4. Engine running rich or lean
  5. Contaminated sensor

Symptoms of P0139 Toyota

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Engine misfires
  4. Check Engine Light illuminated
  5. Failed emissions test

How to Fix P0139 Toyota

  1. Diagnose the code using a scan tool to confirm the issue with the oxygen sensor.
  2. Inspect the wiring and connectors for any damage or corrosion, repairing or replacing as needed.
  3. Check for exhaust leaks near the sensor and repair if necessary.
  4. Replace the oxygen sensor if it is found to be faulty or contaminated.
  5. Clear the code and perform a test drive to ensure the issue has been resolved.

Cost to Fix P0139 Toyota

The typical repair costs for addressing a P0139 code on a Toyota vehicle can range from $150 to $400, depending on the exact cause of the issue and the cost of the replacement parts. This estimate includes the cost of the oxygen sensor itself, which can vary in price depending on the specific model of the vehicle. Additionally, labor costs for this type of repair can range from $80 to $150 per hour, with the total repair time typically taking around 1-2 hours. It is recommended to consult with a local auto repair shop for a more accurate cost estimate based on your specific circumstances.

What does this mean?

Tech Notes for P0139 Toyota

Replacing the Oxygen Sensor Bank 1 Sensor 2 (Rear Oxygen Sensor Bank 1 or Downstream Oxygen Sensor Bank 1) usually takes care of the problem.

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Information for Specific Toyota Models

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 Toyota Code

No Frequently Asked Questions about P0139 Toyota Code found.

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  • can a p0136 code be cause by the catalytic converter being clogged or failing. I smell a sulfur fart smell from exhaust . and it has not power pulling up hill getting on highway I'm always getting the finger. it idles rough at stop lights. 2002 Toyota Tacoma 2.7 4 cylinder motor.

    Reply to Comment

  • Yes, if the P0136 code could be triggered by a faulty or clogged catalytic converter.

    Reply to Comment

  • thank you. Well I have 2 catalytic converters I'm not sure but think I must replace both. local auto parts store say 300 a piece. So any clue where I can find the two connected as one unit cheaper . do you think the o2 sensors will be fine. I'm just a single dad and cant pay a mechanic to track it down so I must do it myself hoping I cant find my two cats cheaper than 600 2002 Toyota Tacoma 2.7 4cyl 2w

    Reply to Comment

  • I recommend remove the catalytic converters and inspect which converter has come apart. Usually the the front one comes apart and clogged the second one. If is clogged, you could just remove all the debris.

    Reply to Comment