P1256 — Engine Coolant Temperature Circuit Open/Short To B+

What Does P1256 Mean?

P1256 is a manufacturer-specific diagnostic trouble code: Engine Coolant Temperature Circuit Open/Short To B+. This code applies to VOLKSWAGEN, FORD, LINCOLN, MERCURY, OTHER 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 P1256

⚠️ Check Engine Light (MIL) illuminated
⚠️ No signal from Engine Coolant Temperature
⚠️ Related system defaulting to backup values
⚠️ Reduced engine performance

Common Causes

🔍 Broken wire in Engine Coolant Temperature circuit
🔍 Disconnected Engine Coolant Temperature electrical connector
🔍 Engine Coolant Temperature internal open circuit failure
🔍 Corroded terminal pins preventing electrical contact

Frequently Asked Questions

What does P1256 mean?

P1256 indicates: Engine Coolant Temperature Circuit Open/Short To B+. The vehicle's computer has detected that the Engine Coolant Temperature is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1256?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1256 for extended periods may cause additional problems.

How much does it cost to fix P1256?

Repair costs for P1256 typically range from $30 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

🔧 Locate and repair broken wire in Engine Coolant Temperature circuit
🔧 Replace damaged Engine Coolant Temperature connector
🔧 Replace Engine Coolant Temperature if internally open

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.

P1256: Engine Coolant Temperature Circuit Open/Short To B+