Torque Converter Clutch Circuit Intermittent
The Powertrain Control Module (PCM) or Transmission Control Module (TCM) detected an intermittent electrical fault or erratic operation in the Torque Converter Clutch (TCC) solenoid circuit. This code is set when the voltage or resistance in the TCC circuit fluctuates outside of expected parameters intermittently, preventing the torque converter from locking up smoothly.
While the vehicle can usually still be driven, an intermittent TCC issue can lead to transmission overheating and internal damage over time. It should be diagnosed and repaired soon to prevent costly transmission failure.
Common symptoms
- Illuminated Check Engine Light
- Transmission slipping or shuddering at highway speeds
- Decreased fuel economy
- Engine stalling when coming to a stop
- Harsh or delayed transmission shifting
Likely causes
- Low or dirty transmission fluid
- Faulty Torque Converter Clutch (TCC) solenoid
- Damaged, loose, or corroded wiring and connectors in the TCC circuit
- Internal transmission fluid pressure issues (e.g., blocked passages)
- Defective torque converter
- Faulty Transmission Control Module (TCM) or PCM
What to check before replacing parts
Check the transmission fluid level and condition
Look for: Look for low fluid levels or burnt, dirty fluid which can cause erratic solenoid operation and intermittent lock-up issues.
Inspect the TCC solenoid wiring harness and connectors
Look for: Look for loose connections, chafed wires, or corrosion that could cause an intermittent open or short circuit in the TCC system.
Test the TCC solenoid resistance using a digital multimeter
Look for: Look for resistance values that fall outside the manufacturer's specified range, indicating a failing or internally shorted solenoid coil.
Monitor TCC operation using a bidirectional scan tool while driving
Look for: Look for the TCC solenoid failing to engage/disengage when commanded, or erratic engine RPM fluctuations indicating intermittent lock-up.
Perform a transmission line pressure test
Look for: Look for pressure readings that are lower than specification, which could indicate internal leaks or pump issues preventing proper TCC engagement.
This page explains the generic P0744 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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