P20B3 — Reductant Heater Coolant Control Valve Circuit Low

What Does P20B3 Mean?

P20B3 is a diagnostic trouble code indicating: Reductant Heater Coolant Control Valve Circuit Low. This code relates to the powertrain system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P20B3

⚠️ Check Engine Light (MIL) illuminated
⚠️ Reductant Heater Coolant Control Valve reading at zero or minimum value
⚠️ Related system not functioning or in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Open or broken wire in Reductant Heater Coolant Control Valve circuit
🔍 Poor ground connection at Reductant Heater Coolant Control Valve
🔍 Faulty Reductant Heater Coolant Control Valve with no output signal
🔍 Disconnected or loose Reductant Heater Coolant Control Valve connector
🔍 Blown fuse in related circuit

Frequently Asked Questions

What does P20B3 mean?

P20B3 indicates: Reductant Heater Coolant Control Valve Circuit Low. The vehicle's computer has detected that the Reductant Heater Coolant Control Valve is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P20B3?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P20B3 for extended periods may cause additional problems.

How much does it cost to fix P20B3?

Repair costs for P20B3 typically range from $20 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

🔧 Repair broken wire or restore ground in Reductant Heater Coolant Control Valve circuit
🔧 Clean and secure Reductant Heater Coolant Control Valve connector and ground points
🔧 Replace failed Reductant Heater Coolant Control Valve

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.

P20B3: Reductant Heater Coolant Control Valve Circuit Low