AutoCodes – Honda – P1509 1999 Honda Civic

P1509 1999 Honda Civic Code - Idle Air Control Valve System High RPM

Quick Answer

The target idle speed is in the Engine Control Module (ECM) memory for various engine conditions (coolant temperature, A/C operation and so on). Common causes include Faulty Idle Air Control Valve, Idle Air Control Valve harness is open or shorted, Idle Air Control Valve circuit 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: P1509 1999 Honda Civic indicates Idle Air Control Valve System High RPM.
Common causes: Common causes include Faulty Idle Air Control Valve, Idle Air Control Valve harness is open or shorted, Idle Air Control Valve circuit 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 11,683

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 25, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1509 1999 Honda Civic Description

The target idle speed is in the Engine Control Module (ECM) memory for various engine conditions (coolant temperature, A/C operation and so on). The ECM keeps the actual idle speed at the target idle speed by switching the Idle Air Control Valve IACV) ON/OFF to control the intake airflow. If the IACV output duty cycle (the length of ON time) is out of a specified range, a malfunction is detected and a DTC is stored.

OBDII Code P1509 1999 Honda Civic - Idle Air Control Valve System High RPM - AutoCodes.com — P1509 1999 Honda Civic Code - Idle Air Control Valve System High RPM

What does this mean?

What are the Possible Causes of the DTC P1509 1999 Honda Civic?

Faulty Idle Air Control Valve
Idle Air Control Valve harness is open or shorted
Idle Air Control Valve circuit poor electrical connection

How to Fix the DTC P1509 1999 Honda Civic?

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 P1509 1999 Honda Civic 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.

Need more information about the P1509 1999 Honda Civic code?

Need more information on how to fix the P1509 1999 Honda Civic code? Get Access to Factory Service Manuals

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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 P1509 1999 Honda Civic Code

1. What are the common symptoms of OBDII code P1509 in a 1999 Honda Civic?

- Common symptoms include high engine idle speed, fluctuating idle speed, stalling at idle, and potential engine misfires.

2. What does the OBDII code P1509 indicate in a 1999 Honda Civic?

- OBDII code P1509 indicates an issue with the Idle Air Control Valve (IACV) system causing high RPM operation.

3. What are the possible causes of OBDII code P1509 in a 1999 Honda Civic?

- Possible causes include a faulty Idle Air Control Valve, vacuum leaks, dirty throttle body, or issues with the engine's air intake system.

4. How can I diagnose the OBDII code P1509 in my 1999 Honda Civic?

- Diagnosis involves checking the Idle Air Control Valve for proper operation, inspecting for vacuum leaks, cleaning the throttle body, and ensuring the air intake system is free of obstructions.

5. Can I drive my 1999 Honda Civic with OBDII code P1509?

- It is not recommended to drive the vehicle with this code as it can cause poor performance, stalling, and potential damage to the engine over time.

6. How can I repair OBDII code P1509 in my 1999 Honda Civic?

- Repair involves replacing a faulty Idle Air Control Valve, fixing any vacuum leaks, cleaning the throttle body, and ensuring proper operation of the air intake system.

7. Is it safe to reset the OBDII code P1509 in my 1999 Honda Civic using a scan tool?

- Yes, resetting the code with a scan tool can help clear the error temporarily, but it is important to address the underlying issue to prevent the code from reoccurring.

8. How much does it cost to repair OBDII code P1509 in a 1999 Honda Civic?

- The cost of repairs can vary depending on the specific issue, but it generally ranges from $100 to $400 for parts and labor.

9. Can a DIY enthusiast fix OBDII code P1509 in a 1999 Honda Civic?

- Yes, some aspects of the repair, such as cleaning the throttle body or checking for vacuum leaks, can be done by a DIY enthusiast with the necessary tools and knowledge.

10. How often does OBDII code P1509 occur in a 1999 Honda Civic?

- OBDII code P1509 related to the Idle Air Control Valve system high RPM can occur sporadically or more frequently depending on the condition of the components and maintenance of the vehicle.