P1559: Idle Speed Control Throttle Position Adaptation Malfunction

VOLKSWAGEN CADILLAC CHEVY CHRYSLER GM GMC OLDSMOBILE BUICK

Severity

Medium

System

Manufacturer-Specific Powertrain

Last reviewed: Jan 1, 0001 Last updated: Jan 1, 0001

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What Does P1559 Mean?

P1559 is a manufacturer-specific diagnostic trouble code: Idle Speed Control Throttle Position Adaptation Malfunction. This code applies to VOLKSWAGEN, CADILLAC, CHEVY, CHRYSLER, GM vehicles. Unlike generic OBD-II codes, manufacturer-specific codes are defined by the vehicle maker and may only apply to certain makes and models.

Symptoms of P1559

⚠️ Check Engine Light (MIL) illuminated
⚠️ Idle Speed Control Throttle Position Adaptation not operating correctly
⚠️ Related system in reduced functionality mode
⚠️ Reduced engine performance

Common Causes

🔍 Idle Speed Control Throttle Position Adaptation has failed or is degraded
🔍 Wiring or connector issue in Idle Speed Control Throttle Position Adaptation circuit
🔍 Related mechanical component affecting Idle Speed Control Throttle Position Adaptation
🔍 Software update needed for ECM/PCM

Frequently Asked Questions

What does P1559 mean?

P1559 indicates: Idle Speed Control Throttle Position Adaptation Malfunction. The vehicle's computer has detected that the Idle Speed Control Throttle Position Adaptation is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1559?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1559 for extended periods may cause additional problems.

How much does it cost to fix P1559?

Repair costs for P1559 typically range from $80 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Inspect Idle Speed Control Throttle Position Adaptation and related wiring
🔧 Replace faulty Idle Speed Control Throttle Position Adaptation

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.