OBD Guide

P20BB

Reductant Heater A Control Circuit Low

P20BB is an OBD-II diagnostic trouble code meaning: Reductant Heater A Control Circuit Low. Common causes: open or short circuit in the heater circuit, heating element malfunction. 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
  • Reduced engine power
  • Increased fuel consumption
  • SCR system error message on dashboard
  • Problems starting in cold weather

Causes

  • Open or short circuit in the heater circuit
  • Heating element malfunction
  • Relay or fuse problems
  • SCR control module malfunction
  • Poor contact in wiring connectors

How to Fix

  1. Check heater circuit fuses and relays
  2. Inspect wiring and connectors for damage
  3. Check the resistance of the heating element
  4. Test the operation of the SCR control module
  5. Replace the faulty heater if necessary

Related codes

Error P20BB by Vehicle Brand

FAQ

What does the P20BB code mean?

P20BB is an OBD-II diagnostic trouble code that indicates: Reductant Heater A Control Circuit Low

What causes a P20BB error code?

The most common causes of P20BB include: Open or short circuit in the heater circuit; Heating element malfunction; Relay or fuse problems; SCR control module malfunction.

How do I fix a P20BB diagnostic trouble code?

To fix P20BB: Check heater circuit fuses and relays. Inspect wiring and connectors for damage. Check the resistance of the heating element. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P20BB?

Yes, but get it checked soon

How much does it cost to fix P20BB?

The estimated repair cost for P20BB is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat