P1503 — Idle Speed Control Valve Closing Solenoid Control Circuit Signal Low

What Does P1503 Mean?

P1503 is a manufacturer-specific diagnostic trouble code: Idle Speed Control Valve Closing Solenoid Control Circuit Signal Low. This code applies to BMW, VOLKSWAGEN, BUICK, CADILLAC, CHEVY 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 P1503

⚠️ Check Engine Light (MIL) illuminated
⚠️ Erratic Idle Speed Control Valve Closing Solenoid readings
⚠️ Related system operating intermittently
⚠️ Reduced engine performance

Common Causes

🔍 Wiring issue in Idle Speed Control Valve Closing Solenoid circuit (damaged, chafed, or corroded)
🔍 Faulty Idle Speed Control Valve Closing Solenoid connector or terminal
🔍 Failed Idle Speed Control Valve Closing Solenoid
🔍 ECM/PCM connection issue

Frequently Asked Questions

What does P1503 mean?

P1503 indicates: Idle Speed Control Valve Closing Solenoid Control Circuit Signal Low. The vehicle's computer has detected that the Idle Speed Control Valve Closing Solenoid is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1503?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1503 for extended periods may cause additional problems.

How much does it cost to fix P1503?

Repair costs for P1503 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 and repair Idle Speed Control Valve Closing Solenoid wiring and connectors
🔧 Replace faulty Idle Speed Control Valve Closing Solenoid

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.

P1503: Idle Speed Control Valve Closing Solenoid Control Circuit Signal Low