Torque Converter Clutch Circuit Intermittent
P0744 indicates an intermittent electrical fault in the torque converter clutch circuit, which controls lockup of the transmission's torque converter. This code sets when the PCM detects an on-and-off signal pattern rather than a consistent state, typically caused by loose connections or wiring damage.
What You Might Notice
- Check Engine Light illuminated intermittently
- Slight decrease in fuel economy
- Occasional torque converter clutch engagement/disengagement
- Possible transmission hunting or shift hesitation
- No significant drivability loss under normal conditions
Most Common Causes
- 1
Loose or corroded connector
The torque converter clutch solenoid connector or transmission harness connector may have loose pins, corrosion, or poor seating causing intermittent signal loss.
- 2
Damaged wiring harness
Wiring to the torque converter clutch solenoid may be pinched, frayed, or partially broken, causing intermittent open or short circuits.
- 3
Faulty torque converter clutch solenoid
The solenoid itself may have an intermittent internal electrical fault or coil resistance issue that causes sporadic operation.
- 4
PCM or transmission control module issue
Rarely, a software glitch or failing control module may generate false intermittent signals on the torque converter circuit.
How to Diagnose It
- 1
Check Loose or corroded connector — The torque converter clutch solenoid connector or transmission harness connector may have loose pins, corrosion, or poor seating causing intermittent signal loss.
- 2
Check Damaged wiring harness — Wiring to the torque converter clutch solenoid may be pinched, frayed, or partially broken, causing intermittent open or short circuits.
- 3
Check Faulty torque converter clutch solenoid — The solenoid itself may have an intermittent internal electrical fault or coil resistance issue that causes sporadic operation.
- 4
Check PCM or transmission control module issue — Rarely, a software glitch or failing control module may generate false intermittent signals on the torque converter circuit.
How to Fix It
- 1
Inspect and repair wiring harness
Visually inspect the wiring harness from the PCM to the torque converter clutch solenoid for damage, pinching, or corrosion. Repair or replace damaged sections and verify secure routing away from heat sources.
- 2
Clean and reseat connectors
Disconnect the torque converter clutch solenoid connector and transmission control connector. Clean terminals with electrical contact cleaner, remove corrosion, and reseat firmly until you hear a click.
- 3
Replace torque converter clutch solenoid
If wiring and connectors are sound, the solenoid coil likely has an internal fault. Locate the solenoid on the transmission, disconnect the harness, remove the bolt, and install a new solenoid.
- 4
Perform transmission fluid and filter service
Contaminated fluid can cause electrical contact issues in the solenoid. Change transmission fluid and filter, then clear the code and monitor for recurrence.
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