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P20B7: Reductant Metering Unit Heater Control Circuit Low

Severity
Medium
System
Powertrain
Last reviewed: Last updated:

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 P20B7 Mean?

P20B7 is a diagnostic trouble code indicating: Reductant Metering Unit Heater Control 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 P20B7

Common Causes

Frequently Asked Questions

What does P20B7 mean?
P20B7 indicates: Reductant Metering Unit Heater Control Circuit Low. 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 P20B7?
You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P20B7 for extended periods may cause additional problems.
How much does it cost to fix P20B7?
Repair costs for P20B7 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 Metering Unit Heater circuit
  • 🔧 Clean and secure Reductant Metering Unit Heater connector and ground points
  • 🔧 Replace failed Reductant Metering Unit Heater
  1. 1
    Find your vehicle above

    Click your make and model for real owner reports and common causes specific to your vehicle.

  2. 2
    Check for recalls

    Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.

  3. 3
    Get a professional diagnosis

    A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

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