P0743Powertrain
Powertrain · SAE
Torque Converter Clutch Solenoid Electrical
Meaning
The control module has detected an electrical fault in the torque converter clutch (TCC) solenoid circuit: short to ground, short to battery voltage, or open circuit. The solenoid does not respond correctly to transmission control module commands.
Common causes
- Short to ground or short to battery in the TCC solenoid control wire
- Open circuit (broken wire or disconnected connector) in the TCC solenoid circuit
- TCC solenoid with open or internally shorted coil
- Oxidised or corroded connectors on the transmission housing or wiring harness
- Internal TCM fault on the TCC solenoid driver
Symptoms
- Check engine light on
- Torque converter does not lock during highway cruising
- Increased fuel consumption
- Transmission in limp mode
- Transmission overheating due to absent lock-up
Severity
High: the electrical fault prevents torque converter lock-up, causing efficiency loss and progressive transmission overheating.
What to do
- Measure TCC solenoid resistance (typically 10–20 Ω); replace if outside specification
- Check supply voltage and command signal at the solenoid connector with a multimeter
- Inspect wiring harness between the TCM and solenoid for shorts or open circuits
- Check transmission connectors for oxidation and corrosion
- Replace the TCM only after ruling out all external faults