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P1129 Jeep Code - Closed Loop Fueling Not Achieved Bank 2

Quick Answer

The P1129 Jeep code indicates that closed-loop fueling has not been achieved on bank 2 of the engine. Common causes include Faulty oxygen sensor on bank 2, Vacuum leaks in the intake system, Fuel injector issues on bank 2. 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
P1129 Jeep indicates Closed Loop Fueling Not Achieved Bank 2.
Common causes
Common causes include Faulty oxygen sensor on bank 2, Vacuum leaks in the intake system, Fuel injector issues on bank 2.
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.
What is this?
Table of contents Created and updated by William Orellana on Aug 25, 2024
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Code P1129 Jeep Description

The P1129 Jeep code indicates that closed-loop fueling has not been achieved on bank 2 of the engine. In a closed-loop system, the engine control module (ECM) uses information from the oxygen sensors to adjust the air/fuel mixture for optimal combustion. When this code is triggered, it means that the ECM is unable to maintain the proper air/fuel ratio on bank 2, which can lead to inefficient fuel consumption, reduced performance, and increased emissions. This issue can impact the overall drivability of the vehicle and may result in poor fuel economy.

OBDII Code P1129 Jeep - Closed Loop Fueling Not Achieved Bank 2
P1129 Jeep Code - Closed Loop Fueling Not Achieved Bank 2

Common Causes of P1129 Jeep

  1. Faulty oxygen sensor on bank 2
  2. Vacuum leaks in the intake system
  3. Fuel injector issues on bank 2
  4. Faulty ECM or wiring issues
  5. Exhaust leaks affecting oxygen sensor readings on bank 2

Symptoms of P1129 Jeep

  1. Decreased fuel efficiency
  2. Rough idle or stalling
  3. Engine hesitation or misfires
  4. Check Engine Light illuminated
  5. Poor acceleration and overall performance

How to Fix P1129 Jeep

  1. Diagnose the specific cause of the issue by conducting a thorough inspection of the oxygen sensor, intake system, fuel injectors, and wiring.
  2. Replace the faulty oxygen sensor on bank 2 if it is determined to be the cause of the problem.
  3. Repair any vacuum leaks in the intake system that may be affecting the air/fuel mixture.
  4. Test and clean or replace fuel injectors on bank 2 if they are found to be faulty.
  5. Check and repair any wiring issues or replace the ECM if necessary.

Cost to Fix P1129 Jeep

The cost of repairing a P1129 Jeep code can vary depending on the specific cause of the issue. In general, replacing an oxygen sensor can cost between $100 and $200, while repairing vacuum leaks or fuel injectors can range from $150 to $500. The total repair cost, including parts and labor, could be anywhere from $200 to $1000 or more. It's important to consult with a certified mechanic to get an accurate estimate based on your vehicle's make and model. Labor rates at auto repair shops can vary, so it's recommended to inquire about pricing before proceeding with the repair.

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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 P1129 Jeep Code

1. What are the common symptoms of OBDII code P1129 on a Jeep indicating Closed Loop Fueling Not Achieved in Bank 2?

- Common symptoms include poor fuel economy, rough idling, engine misfires, and hesitation during acceleration.

2. What are the possible causes of OBDII code P1129 in a Jeep related to Closed Loop Fueling Not Achieved in Bank 2?

- Potential causes include a faulty oxygen sensor, vacuum leaks, issues with the fuel system, or a malfunctioning catalytic converter.

3. How can I diagnose the OBDII code P1129 on my Jeep?

- You can diagnose this code by using an OBDII scanner to read the code, checking for any related symptoms, inspecting the oxygen sensor, and looking for any visible signs of damage or leaks in the engine bay.

4. Is it safe to continue driving my Jeep with OBDII code P1129 indicating Closed Loop Fueling Not Achieved in Bank 2?

- It is not recommended to drive your vehicle with this code as it can lead to further damage to the engine or other components. It is best to address the issue promptly.

5. What is the best course of action to repair OBDII code P1129 on a Jeep?

- The best course of action is to have a professional mechanic diagnose the issue accurately and perform the necessary repairs, which may involve replacing the oxygen sensor, fixing vacuum leaks, or addressing fuel system problems.

6. Can I reset the OBDII code P1129 on my Jeep by disconnecting the battery?

- While disconnecting the battery may clear the code temporarily, it is not a recommended long-term solution. The underlying issue causing the code needs to be properly diagnosed and repaired.

7. Are there any simple DIY checks I can perform to troubleshoot OBDII code P1129 on my Jeep?

- You can visually inspect the oxygen sensor and surrounding components for any signs of damage or wear. Checking for loose or disconnected vacuum hoses can also be helpful.

8. How long does it typically take to repair OBDII code P1129 on a Jeep at a repair shop?

- The repair time can vary depending on the exact cause of the issue and the availability of parts. In general, it may take a few hours to a full day to diagnose and repair the problem.

9. Will OBDII code P1129 on a Jeep cause the check engine light to illuminate?

- Yes, this code will trigger the check engine light to come on, indicating an issue with Closed Loop Fueling Not Achieved in Bank 2 that needs attention.

10. Can extreme weather conditions affect the likelihood of OBDII code P1129 occurring in a Jeep?

- Extreme weather conditions can potentially exacerbate existing issues related to fuel delivery, oxygen sensor performance, and other components, leading to the triggering of this code.

Discuss the causes and fixes for P1129 Jeep OBDII Code

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  • engine light on.got code for misfire,added injector clean, replaced spark plugs, replaced coils, now getting code po152, reset computor, now getting code p1129. this is for my 2007 jeep grand chrokee 3.7 4x4

    Reply to Comment

  • The Oxygen Sensor is the most common problem for the P1129 code, but it may take some driving after all the repairs you did, for the computer to adjust itself. I recommend to clear the code and drive it for a few days, before replacing any more parts.

    Reply to Comment

  • I got a p1129 code with a rough idle occasionally. Dont know what it is any suggestions?

    Reply to Comment

  • Let me check if I can find more information. What model and year is your Jeep?

    Reply to Comment