P21CD Code Definition
P21CD Reductant Quality Module Supply Voltage Low
What Does the Engine Code P21CD Mean?
Character "P" in the first position of Diagnostic Trouble Code (DTC) represents the powertrain system (engine and transmission), "2" in the second position means that this is a ISO/SAE controlled OBD-II (OBD2) DTC. "1" in the third character position in a DTC indicates that the fuel and air metering and auxiliary emission controls is experiencing a malfunction. The last two characters "CD" is DTC number. OBD2 Diagnostic Trouble Code P21CD means that Reductant Quality Module Supply Voltage Low has been detected.
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How Serious Is the Code P21CD?
For now, this issue is not serious. Carly recommends you to check this issue on a regular basis and check if it gets worse later on.
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