AutoCodes – MINI – P0139 MINI

P0139 MINI Code - O2 Sensor Circuit Slow Response Bank 1 Sensor 2

Quick Answer

The Heated Oxygen Sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. 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 MINI indicates O2 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 5,265

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 Apr 12, 2019

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

The Heated Oxygen Sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

OBDII Code P0139 MINI - O2 Sensor Circuit Slow Response Bank 1 Sensor 2 - AutoCodes.com — P0139 MINI Code - O2 Sensor Circuit Slow Response Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0139 MINI?

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 MINI?

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 MINI 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 P0139 MINI 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 P0139 MINI Code

1. What are the common symptoms of OBDII code P0139 in a MINI?

- Common symptoms include poor fuel efficiency, rough idling, and the illumination of the check engine light.

2. What does the O2 Sensor Circuit Slow Response Bank 1 Sensor 2 error code mean in a MINI?

- This code indicates that the downstream oxygen sensor in Bank 1 is not responding as quickly as expected, affecting the fuel-air mixture.

3. What are the possible causes of the P0139 OBDII code in a MINI?

- Causes may include a faulty oxygen sensor, wiring issues, exhaust leaks, or a problem with the engine's fuel system.

4. How can I diagnose the O2 sensor circuit slow response issue in my MINI?

- Diagnosing this issue usually involves checking the oxygen sensor's voltage output, inspecting the sensor's wiring, and looking for any exhaust leaks.

5. Can I continue driving my MINI with the P0139 error code?

- It's generally not recommended to drive with this error code, as it can lead to decreased fuel efficiency and potential damage to the catalytic converter.

6. Is it possible to repair the O2 sensor circuit slow response issue in a MINI myself?

- While some DIY enthusiasts may be able to replace the oxygen sensor themselves, diagnosing and repairing the underlying cause may require professional expertise.

7. How much does it typically cost to repair the P0139 error code in a MINI?

- The cost of repairing this error code can vary depending on the specific issue, but it may range from $100 to $300 for parts and labor.

8. Can a dirty air filter cause the P0139 error code in a MINI?

- While a dirty air filter can affect engine performance, it is not a common cause of the O2 sensor circuit slow response issue.

9. Will resetting the error codes make the P0139 code in my MINI go away?

- Resetting the error codes may temporarily turn off the check engine light, but the underlying issue causing the P0139 code will still need to be addressed.

10. How often should the oxygen sensors be replaced in a MINI to prevent the P0139 error code?

- Oxygen sensors typically last around 100,000 miles, but it's a good idea to follow the manufacturer's recommendations and have them inspected regularly to prevent issues like P0139.