What Does P0743 Mean?
An electrical fault has been detected in the torque converter clutch (TCC) solenoid circuit. The PCM/TCM has measured an abnormal voltage, resistance, or current flow in the TCC solenoid wiring, indicating an open circuit, short to ground, or short to power. The TCC will not function correctly until the electrical issue is resolved.
Common Causes
30%
TCC solenoid internal failure (open or shorted coil windings)
30%
Damaged wiring in the TCC solenoid circuit (broken, corroded, or chafed wires)
20%
Corroded or damaged transmission connector (water intrusion or pin damage)
12%
TCM/PCM driver circuit failure for the TCC solenoid output
8%
Poor ground connection for the solenoid circuit
Diagnostic Steps
1
Measure TCC solenoid resistance at the transmission connector — an open (infinite) or shorted (near zero) reading confirms solenoid failure.
2
Inspect the transmission external connector for corrosion, bent pins, or water intrusion — clean and repair as needed.
3
Perform a voltage drop test on the TCC solenoid supply and ground circuits to identify excessive resistance in the wiring.
4
Check for chafed or broken wires between the TCM and the transmission connector, especially near heat sources and moving components.
5
If wiring and solenoid test good, test the TCM solenoid driver output with a DVOM or oscilloscope to rule out a failed controller.
Estimated Repair Cost
$150 - $1,200
Parts + labor, varies by vehicle and location
An electrical fault has been detected in the torque converter clutch (TCC) solenoid circuit. The PCM/TCM has measured an abnormal voltage, resistance, or current flow in the TCC solenoid wiring, indicating an open circuit, short to ground, or short to power. The TCC will not function correctly until...
The most common cause of P0743 (Torque Converter Clutch Circuit Electrical) is: TCC solenoid internal failure (open or shorted coil windings)
Typical repair costs for P0743 range from $150 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle can generally be driven but the TCC will not engage, leading to reduced fuel economy and increased transmission heat. Avoid long highway trips until repaired to prevent transmission overheating.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0743 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission — Torque Converter
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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