AutoCodes – Hyundai – P0139 2002 Hyundai Elantra

P0139 2002 Hyundai Elantra Code - HO2S 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 2002 Hyundai Elantra indicates HO2S 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 13,807

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 Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0139 2002 Hyundai Elantra 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 2002 Hyundai Elantra - HO2S Circuit Slow Response Bank 1 Sensor 2 - AutoCodes.com — P0139 2002 Hyundai Elantra Code - HO2S Circuit Slow Response Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0139 2002 Hyundai Elantra?

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 2002 Hyundai Elantra?

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 2002 Hyundai Elantra 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 2002 Hyundai Elantra Code

1. What are the common symptoms of OBDII code P0139 on a 2002 Hyundai Elantra?

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

2. What does the OBDII code P0139 "HO2S Circuit Slow Response Bank 1 Sensor 2" mean for a 2002 Hyundai Elantra?

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

3. What are the possible causes of OBDII code P0139 on a 2002 Hyundai Elantra?

- Potential causes include a faulty oxygen sensor, wiring issues, exhaust leaks, a damaged catalytic converter, or a malfunctioning PCM (powertrain control module).

4. How can I diagnose the OBDII code P0139 on my 2002 Hyundai Elantra?

- Diagnose by checking the oxygen sensor's wiring and connections, inspecting for exhaust leaks, and testing the sensor's response using a scan tool.

5. Can I drive my 2002 Hyundai Elantra with OBDII code P0139?

- It is not recommended to drive with this code as it can lead to reduced fuel efficiency and potential damage to the catalytic converter over time.

6. How do I repair OBDII code P0139 on a 2002 Hyundai Elantra?

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

7. Will resetting the check engine light resolve OBDII code P0139 on a 2002 Hyundai Elantra?

- Resetting the light may temporarily turn it off, but if the underlying issue causing the code is not fixed, the light will likely come back on.

8. How much does it cost to fix OBDII code P0139 on a 2002 Hyundai Elantra?

- The cost of repair can vary depending on the specific cause of the code, but it may range from around $100 for a simple sensor replacement to several hundred dollars for more complex repairs.

9. Can a DIY enthusiast fix OBDII code P0139 on a 2002 Hyundai Elantra?

- Depending on the cause, DIY enthusiasts with the necessary tools and knowledge may be able to address simpler issues like sensor replacement or minor wiring repairs.

10. How often does OBDII code P0139 occur in 2002 Hyundai Elantras?

- This code can occur sporadically in older vehicles due to normal wear and tear, but regular maintenance and timely repairs can help prevent its recurrence.