Code result
P21C7
Reductant Control Module Power Relay Control Circuit/Open
Moderate severity
What it means
The control circuit for the relay that supplies power to the SCR/reductant control module is open — module loses main supply on shutdown or never wakes up.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Relay coil open
highOne of the most commonly reported causes for this code — check this first.
Pin pushed back out of connector body
lowLess common, but worth ruling out after the more likely causes.
Cracked solder joint inside the module or sensor
lowLess common, but worth ruling out after the more likely causes.
Related help
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