P20B8

Reductant Metering Unit Heater Control Circuit High

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$56–278 (est.)

Symptoms

Check Engine Light Is On
Reduced engine power
Increased fuel consumption
SCR System Error Message
Problems starting in cold weather

Causes

Open or short circuit in the heater circuit
Malfunction of the heating element of the dosing unit
Problems with the relay or circuit fuse
Engine control unit malfunction
Corrosion or poor contact in connectors

How to Fix

Check heater circuit fuses and relays
Check the integrity of wiring and connectors
Measure the resistance of the heating element
Check control signals from the computer
If necessary, replace the dosing unit or its heater

Related codes

P20B9 P20BA P20BB