Code result
P21CA
Reductant Control Module Supply Voltage Circuit
Moderate severity
What it means
Internal monitoring of the SCR control module reports a fault on its main supply voltage rail — separate from the relay-control diagnostics, this is the module's own self-diagnosis of its supply pin.
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
Module supply pin fault
highOne of the most commonly reported causes for this code — check this first.
Related help
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