OBD Guide

P20B1

Reductant Heater Coolant Control Valve Circuit/Open

P20B1 is an OBD-II diagnostic trouble code meaning: Reductant Heater Coolant Control Valve Circuit/Open. Common causes: open or short circuit in valve circuit, heater solenoid valve malfunction. Estimated repair cost: $28–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$28–89 (est.)

Symptoms

  • Check Engine Light Is On
  • Possible reduction in engine power
  • SCR system fault message
  • Increased consumption of AdBlue reagent
  • Problems starting in cold weather

Causes

  • Open or short circuit in valve circuit
  • Heater solenoid valve malfunction
  • Relay or fuse problems
  • SCR control unit malfunction
  • Corroded contacts or damaged wiring harness

How to Fix

  1. Check heater circuit fuses and relays
  2. Inspect the wiring harness for damage
  3. Check valve resistance and operation
  4. Scan the SCR control unit for additional errors
  5. Replace the faulty valve or repair the wiring

Related codes

Error P20B1 by Vehicle Brand

FAQ

What does the P20B1 code mean?

P20B1 is an OBD-II diagnostic trouble code that indicates: Reductant Heater Coolant Control Valve Circuit/Open

What causes a P20B1 error code?

The most common causes of P20B1 include: Open or short circuit in valve circuit; Heater solenoid valve malfunction; Relay or fuse problems; SCR control unit malfunction.

How do I fix a P20B1 diagnostic trouble code?

To fix P20B1: Check heater circuit fuses and relays. Inspect the wiring harness for damage. Check valve resistance and operation. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P20B1?

Yes, but get it checked soon

How much does it cost to fix P20B1?

The estimated repair cost for P20B1 is $28–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat