What it means
The torque converter clutch circuit has an intermittent fault. The code alone does not establish whether the interruption is electrical or in clutch operation.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The TCC solenoid and clutch let the torque converter lock during conditions chosen by the transmission module. P0744 means the monitored TCC circuit or clutch operation becomes intermittent, so the code alone does not identify whether the interruption is electrical or mechanical. Lockup may cut in and out, sometimes causing a change in engine speed or shudder.
Common causes
Most likely first.
- Intermittent wiring fault
- TCC solenoid failing
- Connector with intermittent contact under vibration
Symptoms
- Intermittent torque converter lockup or shudder may occur
- Check engine or transmission warning light on
How to diagnose it
- Record freeze-frame data and use a scan tool to compare TCC command, lockup status, and engine-to-transmission speed behavior around the fault.
- Inspect the TCC connector and harness for loose terminals, corrosion, fluid intrusion, chafing, or routing that lets vibration pull on the wiring.
- With the circuit disconnected as directed by the manufacturer, check TCC solenoid coil continuity and compare it with the manufacturer's specification.
- Monitor the TCC circuit while gently moving the harness and connector, using the manufacturer's procedure, to locate a connection that cuts in and out.
- If electrical checks pass, investigate whether the TCC clutch applies and releases consistently under the manufacturer's diagnostic conditions.
Common fixes
- Secure a loose connector or repair corroded TCC terminals.
- Repair chafed or strained wiring and route it away from vibration or heat.
- Replace a TCC solenoid that fails electrical or operation checks.
- Repair an internal TCC clutch or hydraulic fault if testing identifies one.
Can I keep driving?
Limit driving if lockup repeatedly drops out, shudder occurs, or the transmission warning appears; avoid towing and long high-speed trips. Continued slipping or shudder can overheat and damage the transmission.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.