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P30C3 on the 2020 Cadillac CT4

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

This code is specific to a manufacturer and is not described here. Its meaning is in the manufacturer's service information.

Bulletins for this model year that name P30C3
PIP5843D2024-04-15. Service bulletin. This Preliminary information communicates to the dealers information related to a Malfunction Indicator Lamp (MIL) Illuminated During Cold Ambient Temperatures with DTCs P30C3 and/or P30BF P30C7 P30CB Setting.
PIP5843C2023-07-17. Service bulletin. This Preliminary information communicates to the dealers information related to a Malfunction Indicator Lamp (MIL) Illuminated During Cold Ambient Temperatures with DTCs P30C3 and/or P30BF P30C7 P30CB Setting.
PIP5843B2023-02-13. Service bulletin. This Preliminary information communicates to the dealers information related to a Malfunction Indicator Lamp (MIL) Illuminated During Cold Ambient Temperatures with DTCs P30C3 and/or P30BF P30C7 P30CB Setting.
PIP5843A2023-01-30. Service bulletin. This Preliminary information communicates to the dealers information related to a Malfunction Indicator Lamp (MIL) Illuminated During Cold Ambient Temperatures with DTCs P30C3 and/or P30BF P30C7 P30CB Setting.
PIP58432022-04-18. Service bulletin. This Preliminary information communicates to the dealers information related to a Malfunction Indicator Lamp (MIL) Illuminated During Cold Ambient Temperatures with DTCs P30C3 and/or P30BF P30C7 P30CB Setting.

5 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.