AutoCodes – Hummer – P0139 Hummer

P0139 Hummer Code - HO2S Slow Response Bank 1 Sensor 2

Quick Answer

The Powertrain Control Module (PCM) provides a .45 volt reference signal to the Heated Oxygen Sensor (HO2S) through the Bank 1 high signal circuit. Common causes include Faulty Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2, HO2S Bank 1 Sensor 2 harness is open or shorted, HO2S Bank 1 Sensor 2circuit 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: P0139 Hummer indicates HO2S Slow Response Bank 1 Sensor 2.
Common causes: Common causes include Faulty Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2, HO2S Bank 1 Sensor 2 harness is open or shorted, HO2S Bank 1 Sensor 2circuit 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 588

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 14, 2021

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

The Powertrain Control Module (PCM) provides a .45 volt reference signal to the Heated Oxygen Sensor (HO2S) through the Bank 1 high signal circuit. When HO2S is cold, less than 392°F (200°C), the sensor signal voltage will be about .45 volt and PCM will keep the system in an open loop. When HO2S is warm, sensor voltage will swing from rich to lean rapidly, at least one switch every 2 seconds, if PCM is in good control of air/fuel mixture. If the oxygen sensor is slow to respond to changes in exhaust oxygen content, the Diagnostic Trouble Code (DTC) will set.

OBDII Code P0139 Hummer - HO2S Slow Response Bank 1 Sensor 2 - AutoCodes.com — P0139 Hummer Code - HO2S Slow Response Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0139 Hummer?

Faulty Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2
HO2S Bank 1 Sensor 2 harness is open or shorted
HO2S Bank 1 Sensor 2circuit poor electrical connection

How to Fix the DTC P0139 Hummer?

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 P0139 Hummer 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 Hummer Code

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

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

2. What does the OBDII code P0139 "HO2S Slow Response Bank 1 Sensor 2" mean for a Hummer?

- This code indicates that the oxygen sensor located downstream of the catalytic converter on bank 1 is not responding as quickly as expected.

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

- Possible causes include a faulty oxygen sensor, wiring issues, exhaust leaks near the sensor, or a problem with the catalytic converter.

4. How can I diagnose the P0139 code in my Hummer?

- Diagnosing the P0139 code involves checking the oxygen sensor's wiring, inspecting for exhaust leaks, testing the sensor's response rate, and scanning for other related codes.

5. Can I drive my Hummer with the P0139 code?

- It is generally safe to drive your vehicle with the P0139 code, but it is recommended to address the issue promptly to prevent further damage and ensure optimal performance.

6. How do I repair the P0139 code in my Hummer?

- Repairing the P0139 code may involve replacing the oxygen sensor, repairing wiring issues, fixing exhaust leaks, or addressing any underlying catalytic converter problems.

7. Can a DIY enthusiast fix the P0139 code in a Hummer?

- Depending on your skill level, you may be able to address the P0139 code yourself by replacing the oxygen sensor or fixing minor wiring issues. However, complex diagnostics may require professional assistance.

8. How much does it cost to repair the P0139 code in a Hummer?

- The cost of repairing the P0139 code can vary depending on the underlying issue, but it may range from $100 to $500 for parts and labor.

9. How often does the P0139 code occur in a Hummer?

- The P0139 code can occur sporadically or persistently, depending on the severity of the issue and how promptly it is addressed.

10. Will resetting the check engine light resolve the P0139 code in a Hummer?

- Resetting the check engine light may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear. It is recommended to diagnose and repair the root cause of the problem.