P20B4

Reductant Heater Coolant Control Valve Circuit High

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$28–89 (est.)

Symptoms

Check Engine light comes on
Possible messages indicating a malfunction of the SCR system
Reduced efficiency of the emission treatment system
In cold weather, problems with starting the SCR system may occur.

Causes

Broken or damaged wiring to the valve
Malfunction of the cooling valve itself
Poor contact in circuit connectors
Problems with the engine ECU
Short circuit in the circuit

How to Fix

Check the integrity of the valve circuit wiring and connectors
Measure valve resistance, compare with standards
Check power and ground circuit
If necessary, replace the cooling valve
Scan the system for other related codes

Related codes

P20B3 P20B5 P20B6