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P1738 on the 2025 Mazda CX-30

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 P1738
05-001-25a2025-12-04. Service bulletin. Some customers may see the A/T warning light on during (or immediately after) engine start-up with DTCs P073D:00-TCM / P1738:00-TCM stored. P073D:00-TCM: Turbine/input shaft speed sensor: Sensor output range malfunction P1738:00-TCM: Automatic transaxle internal malfunction This concern is caused by improper TCM logic. To eliminate this concern, the TCM control software has been modified to change the DTC detection logic, preventing DTC judgment during start-up.

1 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.