P21CD

Reductant Quality Module Supply Voltage Low

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$56–278 (est.)

Symptoms

Check Engine light comes on
Reduced engine power
Possible SCR error messages
Increased consumption of AdBlue reagent
Problems starting the engine in cold weather

Causes

Problems with wiring to the reagent quality module
Faulty relay or module power fuse
Short circuit in the module circuit
Malfunction of the reagent quality module itself
Module grounding problems

How to Fix

Check fuses and relays of the module power supply circuit
Diagnose the condition of wiring and connectors
Check the supply voltage on the module
Test ground circuit resistance
If necessary, replace the reagent quality module

Related codes

P21CE P21CF P2200