Torque Converter Clutch Circuit Stuck On
The P0742 code indicates that the powertrain control module (PCM) has detected the torque converter clutch (TCC) is stuck in the engaged (on) position when it should be disengaged. This can cause the engine to stall at idle, poor fuel economy, and transmission overheating. The TCC solenoid or valve may be stuck, or there could be a wiring issue.
1. Symptoms You Will Notice
- Engine stalls when coming to a stop
- Rough idle or shuddering
- Poor fuel economy
- Transmission overheating
2. Most Common Causes
- TCC solenoid stuck mechanically or damaged
- Low, dirty, or degraded transmission fluid
- Internal hydraulic or mechanical failure in the valve body or torque converter
- Solenoid circuit wiring shorted to voltage or open
- Solenoid connector with corroded or loose terminals
- Faulty powertrain control module (PCM)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and check freeze frame data.
Step 2: Inspect transmission fluid level and condition.
Step 3: Test TCC solenoid resistance and wiring continuity.
Step 4: Perform a TCC solenoid functional test using a scan tool.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. Driving with the TCC stuck on can cause transmission damage, stalling, and loss of vehicle control. Have it inspected immediately.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the solenoid or valve body needs replacement. Labor costs vary by shop.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.