AutoCodes – Hyundai – P1508 Hyundai

P1508 Hyundai Code - Idle Speed Control Actuator Signal High

Quick Answer

The Idle Speed Control Actuator (ISCA) valve is installed on the intake manifold and controls the intake airflow that is bypassed around the throttle plate to keep constant engine speed when the throttle valve is closed. Common causes include Faulty Idle Speed Control Actuator (ISCA) valve, Idle Speed Control Actuator (ISCA) valve harness is open or shorted, Idle Speed Control Actuator (ISCA) 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: P1508 Hyundai indicates Idle Speed Control Actuator Signal High.
Common causes: Common causes include Faulty Idle Speed Control Actuator (ISCA) valve, Idle Speed Control Actuator (ISCA) valve harness is open or shorted, Idle Speed Control Actuator (ISCA) 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 9,136

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

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

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1508 Hyundai Description

The Idle Speed Control Actuator (ISCA) valve is installed on the intake manifold and controls the intake airflow that is bypassed around the throttle plate to keep constant engine speed when the throttle valve is closed. The function of the ISCA valve is to maintain idle speed according to various engine loads and conditions, and also to provide additional air during starting. The ISCA valve consists of an opening coil, a closing coil, and a permanent magnet. Based on information from various sensors, the ECM controls both coils by grounding their control circuits. According to the control signals from the ECM, the valve rotor rotates to control the by pass airflow into the engine.

OBDII Code P1508 Hyundai - Idle Speed Control Actuator Signal High - AutoCodes.com — P1508 Hyundai Code - Idle Speed Control Actuator Signal High

What does this mean?

What are the Possible Causes of the DTC P1508 Hyundai?

Faulty Idle Speed Control Actuator (ISCA) valve
Idle Speed Control Actuator (ISCA) valve harness is open or shorted
Idle Speed Control Actuator (ISCA) valve circuit poor electrical connection

How to Fix the DTC P1508 Hyundai?

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 P1508 Hyundai 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.