Parts
$20-200
P0743 — Torque Converter Clutch Solenoid Circuit Electrical
CAUTIONIs it safe to drive? The TCC solenoid has an electrical fault (open or short). Lockup won't function correctly — economy suffers and the transmission works harder at cruise.
What P0743 means
Unlike P0741 (performance) or P0742 (stuck on), P0743 is a confirmed electrical circuit fault in the TCC solenoid wiring or the solenoid itself. Usually a simpler fix than internal mechanical issues.
Most likely causes (in order)
- Failed TCC solenoid (open or shorted coil)
- Wiring fault — open circuit or short in the solenoid wiring
- Corroded connector at the solenoid or TCM
- Low or contaminated fluid fouling the solenoid
Symptoms you might notice
- No TCC lockup at cruise
- High RPM at highway speed
- Poor fuel economy
What to check first
Measure the TCC solenoid resistance at the trans connector (typically 10-20 ohms — check your make's spec). Open (OL) or near-zero = solenoid. Correct resistance = wiring or TCM.
Repair cost & difficulty
Labor
0.5-3 hr
Difficulty
DIY-friendly