OBD Guide

P20B7

Reductant Metering Unit Heater Control Circuit Low

P20B7 is an OBD-II diagnostic trouble code meaning: Reductant Metering Unit Heater Control Circuit Low. Common causes: open or short circuit in the heater circuit, poor contact in control circuit connectors. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine Light Is On
  • Possible SCR System Error Message
  • Reduced engine power in cold weather
  • Increased fuel consumption
  • Increased NOx emissions

Causes

  • Open or short circuit in the heater circuit
  • Poor contact in control circuit connectors
  • Module heating element malfunction
  • Problems with the SCR control unit
  • Contact corrosion due to reagent exposure

How to Fix

  1. Check the integrity of the wiring and contacts in the heater circuit
  2. Measure the resistance of the heating element
  3. Check the voltage at the module connectors
  4. If necessary, replace the reagent dosing module
  5. Reset the error code and test run the system

Related codes

Error P20B7 by Vehicle Brand

FAQ

What does the P20B7 code mean?

P20B7 is an OBD-II diagnostic trouble code that indicates: Reductant Metering Unit Heater Control Circuit Low

What causes a P20B7 error code?

The most common causes of P20B7 include: Open or short circuit in the heater circuit; Poor contact in control circuit connectors; Module heating element malfunction; Problems with the SCR control unit.

How do I fix a P20B7 diagnostic trouble code?

To fix P20B7: Check the integrity of the wiring and contacts in the heater circuit. Measure the resistance of the heating element. Check the voltage at the module connectors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P20B7?

Yes, but get it checked soon

How much does it cost to fix P20B7?

The estimated repair cost for P20B7 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat