Drive with caution — fix soon.
This code indicates an electrical problem in the torque converter clutch solenoid circuit, such as an open, short, or out-of-range signal, rather than a purely mechanical fault. It's commonly caused by a failed TCC solenoid, damaged wiring, or a bad connector. Repairs usually involve replacing the solenoid or fixing the wiring, which is often less expensive than internal transmission work.
$100 – $1000
Varies by vehicle and root cause.
Usually yes, since it's typically an electrical issue and the car still drives, but don't ignore it. The converter may not lock up, adding heat to the transmission, so get it checked soon.
A wiring repair can be quite cheap, while replacing the TCC solenoid generally runs $150 to $600. If the solenoid is internal and requires dropping the pan or valve body, costs can reach $1,000.
It's moderately serious. The car stays drivable, but because the torque converter clutch isn't working right, leaving it unfixed can cause extra wear and heat in the transmission.
P0743 specifically flags an electrical fault in the torque converter clutch circuit, like a bad solenoid or wiring, which is why diagnosis usually starts with testing the circuit rather than the transmission internals.