Possible Causes

WARNING: This page is about a different car, the 2002 Mazda Millenia and 2001 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.

Following items are possible causes for DTC P1743:

TCC control solenoid malfunction.
Open or short to ground or power in TCC circuits between PCM and TCC solenoid.
Damaged connectors or wiring harness between TCC solenoid and PCM.
PCM malfunction.