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Engine-Codes – Honda – P1129 2009 Honda Accord

P1129 2009 Honda Accord Code - Manifold Absolute Pressure Sensor Circuit Higher Than Expected

Quick Answer

The P1129 code on a 2009 Honda Accord indicates a problem with the Manifold Absolute Pressure (MAP) sensor circuit, specifically that the sensor is reading a higher pressure than expected by the engine control module (ECM). Common causes include Faulty MAP sensor, Damaged or disconnected sensor wiring harness, Clogged or leaking intake manifold. 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 2009 Honda Accord indicates Manifold Absolute Pressure Sensor Circuit Higher Than Expected.
Common causes
Common causes include Faulty MAP sensor, Damaged or disconnected sensor wiring harness, Clogged or leaking intake manifold.
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 Sep 12, 2024
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Code P1129 2009 Honda Accord Description

The P1129 code on a 2009 Honda Accord indicates a problem with the Manifold Absolute Pressure (MAP) sensor circuit, specifically that the sensor is reading a higher pressure than expected by the engine control module (ECM). The MAP sensor is a crucial component that measures the pressure inside the intake manifold, providing data to the ECM to calculate the air-fuel mixture for optimal engine performance. When the sensor reports a pressure that is higher than expected, it can lead to a variety of issues that affect the vehicle's performance and efficiency.

OBDII Code P1129 2009 Honda Accord - Manifold Absolute Pressure Sensor Circuit Higher Than Expected
P1129 2009 Honda Accord Code - Manifold Absolute Pressure Sensor Circuit Higher Than Expected

Common Causes of P1129 2009 Honda Accord

  1. Faulty MAP sensor
  2. Damaged or disconnected sensor wiring harness
  3. Clogged or leaking intake manifold
  4. ECM malfunction
  5. Vacuum leaks in the intake system

Symptoms of P1129 2009 Honda Accord

  1. Check Engine Light illuminated
  2. Decreased fuel efficiency
  3. Rough idling or stalling
  4. Hesitation or lack of power during acceleration
  5. Increased emissions

How to Fix P1129 2009 Honda Accord

  1. Begin by using a diagnostic scanner to retrieve the specific trouble code and confirm that it is indeed P1129 related to the MAP sensor circuit.
  2. Inspect the MAP sensor and its wiring harness for any visible damage or loose connections. Replace the sensor if necessary.
  3. Check the intake manifold for any signs of clogs or leaks. Clean or repair as needed.
  4. Clear the trouble code from the ECM's memory using the diagnostic scanner.
  5. Test drive the vehicle to ensure that the issue has been resolved and that the check engine light does not reappear.

Cost to Fix P1129 2009 Honda Accord

The cost of repairing a P1129 code on a 2009 Honda Accord can vary depending on the specific cause of the issue. Typically, the cost of a new MAP sensor ranges from $50 to $150, while the labor cost for the repair can range from $100 to $200. In total, the repair for this issue could cost anywhere from $150 to $350. It is important to note that these are rough estimates, and actual costs may vary based on factors such as location, labor rates, and any additional parts or repairs that may be needed. It is recommended to consult with a qualified mechanic or auto repair shop for a more accurate cost estimate.

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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 2009 Honda Accord Code

1. What are the common symptoms of OBDII code P1129 on a 2009 Honda Accord?

- Common symptoms include poor engine performance, rough idling, stalling, and potentially reduced fuel efficiency.

2. What does the OBDII code P1129 on a 2009 Honda Accord indicate?

- This code indicates that the Manifold Absolute Pressure (MAP) sensor circuit is detecting a higher than expected pressure.

3. What are some possible causes of OBDII code P1129 on a 2009 Honda Accord?

- Possible causes include a faulty MAP sensor, a vacuum leak, a clogged or dirty air filter, or issues with the wiring or connections in the sensor circuit.

4. How can I diagnose the OBDII code P1129 on my 2009 Honda Accord?

- Diagnosis typically involves using a scan tool to read the code and then performing a visual inspection of the MAP sensor, checking for vacuum leaks, and testing the sensor's electrical connections.

5. Can I continue driving my 2009 Honda Accord with OBDII code P1129?

- It's not recommended to continue driving with this code as it can lead to further engine damage and potentially unsafe driving conditions.

6. How can I repair OBDII code P1129 on a 2009 Honda Accord?

- Repair options may include replacing the MAP sensor, fixing any vacuum leaks, cleaning or replacing the air filter, or addressing any wiring issues in the sensor circuit.

7. Is it possible to reset the OBDII code P1129 on a 2009 Honda Accord without fixing the underlying issue?

- While you can clear the code with a scan tool, it will likely reappear if the root cause is not addressed.

8. How much does it typically cost to repair OBDII code P1129 on a 2009 Honda Accord?

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

9. Can a DIY enthusiast fix OBDII code P1129 on a 2009 Honda Accord?

- Depending on the root cause and the individual's skill level, some DIY enthusiasts may be able to tackle the repair themselves, especially if it involves simple tasks like replacing the air filter or cleaning sensor connections.

10. Will OBDII code P1129 cause my 2009 Honda Accord to fail an emissions test?

- Yes, this code can cause your vehicle to fail an emissions test, so it's important to address the issue promptly to ensure your vehicle meets regulatory standards.

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