Engine-CodesChrysler – P1129 Chrysler

P1129 Chrysler Code - Closed Loop Fueling Not Achieved Bank 2

Quick Answer

The P1129 Chrysler code indicates that closed-loop fueling has not been achieved in Bank 2 of the vehicle's engine. Common causes include Malfunctioning oxygen sensor in Bank 2, Vacuum leak in the intake system, Faulty mass airflow sensor. 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 Chrysler indicates Closed Loop Fueling Not Achieved Bank 2.
Common causes
Common causes include Malfunctioning oxygen sensor in Bank 2, Vacuum leak in the intake system, Faulty mass airflow sensor.
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.
Table of contents Created and updated by William Orellana on Sep 09, 2024
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Code P1129 Chrysler Description

The P1129 Chrysler code indicates that closed-loop fueling has not been achieved in Bank 2 of the vehicle's engine. Closed-loop fueling refers to the system in which the engine control module (ECM) adjusts the air-fuel mixture based on feedback from oxygen sensors in the exhaust system. When the vehicle is in closed-loop operation, it means that it is running efficiently and with optimal fuel consumption.

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

Common Causes of P1129 Chrysler

  1. Malfunctioning oxygen sensor in Bank 2
  2. Vacuum leak in the intake system
  3. Faulty mass airflow sensor
  4. Issues with the fuel injectors
  5. Malfunctioning ECM

Symptoms of P1129 Chrysler

  1. Decreased fuel efficiency
  2. Rough idling or engine hesitation
  3. Engine stalling
  4. Check Engine Light illuminated on the dashboard

How to Fix P1129 Chrysler

  1. Diagnose the specific cause of the issue by using a scan tool to retrieve the fault codes and data from the vehicle's ECM.
  2. Inspect the oxygen sensor in Bank 2 to determine if it is functioning correctly. Replace if necessary.
  3. Check for any vacuum leaks in the intake system and repair as needed.
  4. Test the mass airflow sensor and fuel injectors for proper operation. Replace any faulty components.
  5. If all components check out, consider inspecting the ECM for any issues and reprogramming or replacing if necessary.

Cost to Fix P1129 Chrysler

The typical repair cost for addressing the P1129 Chrysler code can range from $200 to $600, including parts and labor. However, the actual cost can vary depending on the specific cause of the issue, the cost of replacement parts, and the labor rates at the auto repair shop. It is advisable to consult with a professional mechanic to get an accurate estimate based on the specific circumstances of the vehicle.

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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 Chrysler Code

1. What does the OBDII code P1129 mean on a Chrysler?

P1129 indicates that the engine control module (ECM) has detected that closed-loop fuel control was not achieved for Bank 2, meaning the system is unable to properly adjust air-fuel ratios.

2. What are the symptoms of a P1129 code on a Chrysler?

Common symptoms include poor fuel economy, rough idling, hesitation during acceleration, increased emissions, and in some cases, an illuminated check engine light.

3. What causes the P1129 code on a Chrysler vehicle?

Potential causes include a faulty oxygen sensor on Bank 2, a vacuum leak, fuel delivery issues (such as a clogged fuel injector), a damaged mass airflow (MAF) sensor, or exhaust leaks.

4. Can a dirty air filter cause the P1129 code?

Yes, a dirty or clogged air filter can restrict airflow and contribute to the P1129 code by affecting the air-fuel ratio.

5. How is the P1129 code diagnosed?

A mechanic will use an OBDII scanner to confirm the code, inspect the Bank 2 oxygen sensor, check for vacuum and exhaust leaks, test the fuel system, and examine the MAF sensor for proper operation.

6. Is it safe to drive with the P1129 code on a Chrysler?

Driving with a P1129 code is not recommended, as it can lead to poor engine performance, reduced fuel efficiency, and potential long-term damage to the catalytic converter.

7. Can a faulty oxygen sensor alone trigger the P1129 code?

Yes, a malfunctioning oxygen sensor on Bank 2 is a common cause of the P1129 code, as it affects the ECM's ability to achieve closed-loop operation.

8. How do you fix a P1129 code on a Chrysler?

Repairs may include replacing a faulty oxygen sensor on Bank 2, repairing vacuum leaks, cleaning or replacing the MAF sensor, inspecting and cleaning fuel injectors, or replacing the air filter.

9. What tools are needed to troubleshoot the P1129 code?

Diagnostic tools include an OBDII scanner, a multimeter for testing sensors, a smoke machine for detecting vacuum leaks, and possibly specialized tools for inspecting the fuel system.

10. Can a software update fix the P1129 code on a Chrysler?

In rare cases, an ECM software update from the manufacturer may address the P1129 code if it’s caused by outdated programming. However, hardware issues are more common causes.

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