P056D

Reductant Control Module System Voltage

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–167 (est.)

Symptoms

Check Engine Light Is On
Reduced engine power
Increased fuel consumption
Possible SCR error messages on the dashboard

Causes

Battery or alternator problems
Open or short circuit in module wiring harness
Faulty connections or corroded connectors
Reagent control module failure
Problems with the relay or circuit fuse

How to Fix

Check battery voltage and generator operation
Visually inspect the wiring harness and module connectors for damage
Check the fuse and relay of the module power supply circuit
Measure the voltage at the module terminals with the ignition on
If necessary, replace the reagent control module

Related codes

P20EE P207F P208A P208E