P21C7

Reductant Control Module Power Relay/Relays Control Circuit/Open

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–89 (est.)

Symptoms

Check Engine Light Is On
Reduced engine power
Increased fuel consumption
Possible transition to emergency mode
Increased NOx emissions

Causes

Open circuit in the relay control circuit
Faulty regenerator module relay
Wiring Harness Problems
Reducer module malfunction
Short circuit in the circuit

How to Fix

Check the integrity of the relay control circuit
Check relay functionality
Inspect the wiring harness for damage
Check the power supply and ground of the reducing agent module
If necessary, replace the relay or restorer module

Related codes

P21C8 P21C9 P21CA