P20B5

Reductant Metering Unit Heater Control Circuit/Open

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
Increased NOx emissions
Possible starting problems in cold weather

Causes

Open or short circuit in the heater circuit
Dosing unit heater malfunction
Relay or fuse problems
SCR control module malfunction
Poor contact in connectors

How to Fix

Check the integrity of the heater circuit
Check the resistance of the heating element
Inspect connectors and wiring for damage
Check fuses and relays
If necessary, replace the reagent dosing unit

Related codes

P20B4 P20B6 P20B8