How much does it cost to fix P0743?

DIY repair typically costs $15–$120 for parts. Professional repair runs $200–$900 including parts and labor.

P0743

Powertrain

Moderate

Torque Converter Clutch Circuit Electrical

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P0743 specifically points to an electrical problem in the torque converter clutch solenoid circuit. Unlike P0741 or P0742 which indicate performance or mechanical issues, P0743 means the PCM has detected an abnormal voltage, resistance, or current flow in the wiring that controls the TCC solenoid. This is often caused by wiring damage, connector corrosion, or an internal solenoid electrical failure.

Symptoms can vary depending on whether the electrical issue causes the TCC to stay off, stay on, or behave erratically. You'll likely notice reduced fuel economy, and possibly shuddering at highway speeds or occasional stalling when coming to a stop. The behavior may be intermittent since electrical faults can come and go with heat and vibration.

This code is somewhat more straightforward to diagnose than other TCC codes because it points to an electrical issue. A technician can measure the solenoid's resistance, check for proper voltage at the connector, and inspect the wiring harness for damage. Wiring repairs or solenoid replacement are typically less expensive than torque converter replacement, making accurate diagnosis especially valuable with this code.

Severity

Moderate — Address SoonThis Week

Symptoms

•Check Engine light illuminated
•Decreased fuel economy
•Transmission may shudder during highway driving
•Erratic torque converter lockup behavior
•Engine may stall occasionally when stopping

Likely Causes

Damaged wiring or connectors in TCC circuit35%

Corroded, chafed, or broken wires between the PCM/TCM and the TCC solenoid are the primary cause. Heat from the transmission can degrade wiring insulation over time.

Faulty TCC solenoid (electrical failure)30%

The solenoid's internal coil may have an open circuit, short circuit, or resistance outside the normal range, preventing proper electrical operation.

Poor ground connection15%

A corroded or loose ground connection for the transmission control circuit can cause erratic solenoid behavior and trigger this electrical code.

Contaminated transmission fluid affecting solenoid12%

Metal particles or debris in the fluid can interfere with the solenoid's electromagnetic operation, causing electrical performance issues.

PCM/TCM internal fault8%

The control module's solenoid driver circuit may be damaged, preventing proper voltage delivery to the TCC solenoid.