Failed throttle body adaptation (35% likelihood): The throttle body adaptation procedure was interrupted or failed, leaving the ECU unable to learn the correct idle throttle position. This commonly occurs after a battery disconnect or ECU reset. Dirty throttle body affecting closed position (25% likelihood): Carbon deposits prevent the throttle plate from fully closing, causing the closed-position voltage to be higher than the ECU expects during its adaptation routine. Faulty throttle position sensor (20% likelihood): One of the dual-track position sensors inside the throttle body is providing a voltage below the expected range at the idle/closed position. Wiring or connector issue (12% likelihood): A high-resistance connection or partially damaged wire reduces the throttle position signal voltage reaching the ECU during the adaptation learning process. Vacuum leak affecting idle control (8% likelihood): An unmetered air leak causes the ECU to struggle maintaining idle speed, leading to repeated failed adaptation attempts and the storage of this fault code.

How much does it cost to fix P1564?

DIY repair typically costs $0–$50 for parts. Professional repair runs $80–$350 including parts and labor.

P1564

Powertrain

Moderate

Volkswagen/Audi

Idle Speed Control — Throttle Position Low Voltage During Adaptation

What could P1564 mean for your vehicle?

Add your vehicle to explore possible causes and next checks. AI guidance helps you investigate; it does not confirm a diagnosis.

P1564 is a Volkswagen/Audi-specific code (VAG fault 17972) indicating that the throttle position sensor is reading a lower-than-expected voltage during the idle speed control adaptation process. This adaptation is a learned procedure where the ECU calibrates the throttle body's rest position and minimum airflow. When the voltage falls below the expected threshold, the ECU cannot properly calibrate idle speed control.

This code commonly appears after a battery replacement, ECU reset, or throttle body cleaning without performing the required adaptation procedure afterward. On VW and Audi vehicles, anytime the throttle body is cleaned, replaced, or the battery is disconnected for an extended period, the throttle body adaptation must be re-learned. Without this adaptation, the ECU doesn't know the throttle plate's true resting position.

The fix is often as simple as performing a throttle body adaptation using VCDS (VAG-COM) or OBDeleven — no parts required. Connect the diagnostic tool, navigate to the throttle body adaptation channel, and run the automatic procedure with the ignition on but engine off. If the adaptation fails repeatedly, the throttle body likely needs cleaning first. Remove it, clean the plate and bore with throttle body cleaner, reinstall, and re-attempt adaptation. This is one of the most affordable and DIY-friendly VW/Audi repairs, often costing nothing if you already have a VCDS cable or OBDeleven dongle.

Severity

Moderate — Address SoonThis Week

Symptoms

•Check Engine Light on
•Idle speed is too high or too low
•Engine idle is unstable or hunting
•EPC light may illuminate intermittently
•Stalling when decelerating to a stop
•Slightly rough engine response off idle

Likely Causes

Failed throttle body adaptation35%

The throttle body adaptation procedure was interrupted or failed, leaving the ECU unable to learn the correct idle throttle position. This commonly occurs after a battery disconnect or ECU reset.

Dirty throttle body affecting closed position25%

Carbon deposits prevent the throttle plate from fully closing, causing the closed-position voltage to be higher than the ECU expects during its adaptation routine.

Faulty throttle position sensor20%

One of the dual-track position sensors inside the throttle body is providing a voltage below the expected range at the idle/closed position.

Wiring or connector issue12%

A high-resistance connection or partially damaged wire reduces the throttle position signal voltage reaching the ECU during the adaptation learning process.

Vacuum leak affecting idle control8%

An unmetered air leak causes the ECU to struggle maintaining idle speed, leading to repeated failed adaptation attempts and the storage of this fault code.