P20B6: Reductant Metering Unit Heater Control Circuit Performance

Severity

Medium

System

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 P20B6 Mean?

P20B6 is a diagnostic trouble code indicating: Reductant Metering Unit Heater Control Circuit Performance. This code relates to the powertrain system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P20B6

⚠️ Check Engine Light (MIL) illuminated
⚠️ Reductant Metering Unit Heater not meeting expected output
⚠️ Degraded performance of related system
⚠️ Reduced engine performance

Common Causes

🔍 Reductant Metering Unit Heater degraded from age or contamination
🔍 Mechanical wear in Reductant Metering Unit Heater or related parts
🔍 Restriction or blockage affecting Reductant Metering Unit Heater
🔍 Calibration drift in Reductant Metering Unit Heater

Frequently Asked Questions

What does P20B6 mean?

P20B6 indicates: Reductant Metering Unit Heater Control Circuit Performance. The vehicle's computer has detected that the Reductant Metering Unit Heater is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P20B6?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P20B6 for extended periods may cause additional problems.

How much does it cost to fix P20B6?

Repair costs for P20B6 typically range from $50 to $400, 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 Reductant Metering Unit Heater for contamination or wear
🔧 Replace Reductant Metering Unit Heater
🔧 Address any related mechanical faults

1
Find your vehicle above
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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.