P1748 Diagnostic Trouble Code (8 interpretations)

The control module detected a fault associated with the Transmission Control Module Self Test circuit or function; the stored code identifies the affected component rather than a single failure mode. This is the manufacturer-specific definition used by BMW.

The control module detected improper operation of the TCM - ECM Communication Line #2. This is the manufacturer-specific definition used by Hyundai.

The control module detected a fault associated with the Pressure Regulator 5 circuit or function; the stored code identifies the affected component rather than a single failure mode. This is the manufacturer-specific definition used by Jaguar.

The control module detected improper operation of the AT - electronic pressure control solenoid. This is the manufacturer-specific definition used by Mazda.

The control module detected a fault associated with the Control unit defective (Relay sticks) circuit or function; the stored code identifies the affected component rather than a single failure mode. This is the manufacturer-specific definition used by Porsche.

The control module detected an interruption (open circuit) in the Exchanger management solenoid valve output fault circuit. Documented for the AL4 automatic gearbox ECU on Peugeot applications; the same PSA control units are also fitted to Citroën models.

The control module's internal test reported the Transmission control module (TCM) as faulty. This is the manufacturer-specific definition used by Audi.

The control module detected a fault associated with the Transmission Control Unit Self - Check circuit or function; the stored code identifies the affected component rather than a single failure mode. This is the manufacturer-specific definition used by Volkswagen.