P0743 means Torque Converter Clutch Circuit Electrical. There is an open or short in the torque converter clutch solenoid circuit. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0743 means
Electronically controlled automatics are run by a transmission control module (TCM), a separate box or part of the engine computer. It reads speed sensors, the range sensor and fluid temperature to decide when to shift, and drives solenoids that apply clutches and the torque converter clutch. Many basic code readers only show the generic P0700; a scan tool that reads the transmission module shows the specific fault. Check fluid level and condition first, since low or burnt fluid causes many transmission codes.
P0743 symptoms
- No converter lockup and higher cruise RPM
- Lower fuel economy
- Check engine light
Common causes of P0743
- Failed TCC solenoid
- Internal harness or case connector fault
- TCM driver fault
How to diagnose P0743
- Measure TCC solenoid resistance at the case connector
- Inspect the case connector for fluid intrusion
- Check the control signal from the module
Can you drive with P0743?
Usually yes, but extra heat from an unlocked converter is hard on fluid.
P0743 tips
Electrical TCC codes often trace to the case connector, where fluid can wick into the wiring. Clean or replace the connector before replacing the solenoid.
Will P0743 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0743 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0740 | Torque Converter Clutch Circuit Malfunction |
| P0741 | Torque Converter Clutch Circuit Performance or Stuck Off |
| P0744 | Torque Converter Clutch Circuit Intermittent |
Guides that help
When it is more than a sensor
If the fault turns out to be internal (worn clutches, a failed converter or a damaged valve body), compare a rebuild with a replacement in transmission rebuild vs replacement and transmission replacement cost, identify your unit with what transmission do I have?, and browse our transmissions.
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