OBD Guide

P221C

Reductant Heater B Current Too Low

P221C is an OBD-II diagnostic trouble code meaning: Reductant Heater B Current Too Low. Common causes: reagent heating element malfunction, open or short circuit in the heater circuit. 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 comes on
  • Reduced engine power
  • Increased fuel consumption
  • Problems with the SCR system
  • Possible error messages in the AdBlue system

Causes

  • Reagent heating element malfunction
  • Open or short circuit in the heater circuit
  • Poor contact in wiring connectors
  • Faulty relay or fuse
  • Problems with the SCR control unit

How to Fix

  1. Check heater circuit fuses and relays
  2. Check the integrity of wiring and connectors
  3. Measure the resistance of the heating element
  4. Check the operation of the SCR control unit
  5. Replace the faulty heating element if necessary

Related codes

Error P221C by Vehicle Brand

FAQ

What does the P221C code mean?

P221C is an OBD-II diagnostic trouble code that indicates: Reductant Heater B Current Too Low

What causes a P221C error code?

The most common causes of P221C include: Reagent heating element malfunction; Open or short circuit in the heater circuit; Poor contact in wiring connectors; Faulty relay or fuse.

How do I fix a P221C diagnostic trouble code?

To fix P221C: Check heater circuit fuses and relays. Check the integrity of wiring and connectors. Measure the resistance of the heating element. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P221C?

Yes, but get it checked soon

How much does it cost to fix P221C?

The estimated repair cost for P221C is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat