Torque Converter Clutch Circuit Stuck On
What does P0742 mean?
The P0742 code means the vehicle's onboard diagnostic system has detected: Torque Converter Clutch Circuit Stuck On. This is a critical severity code.
Common Symptoms
- Check Engine Light illuminated
- Engine stalls when coming to a stop
- Vehicle bucks or shudders at low speeds
- Harsh engagement when shifting from Park
Probable Causes (Ranked by Likelihood)
- TCC solenoid stuck in the on position Very High
- Valve body TCC apply valve stuck High
- Wiring short keeping TCC solenoid energized Moderate
- TCM commanding TCC on at wrong time Low
Step-by-Step Diagnostic Procedure
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Monitor TCC status on a scan tool -- if it shows locked at low speeds or at a stop, the TCC is stuck on
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Check TCC solenoid for internal mechanical failure
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Inspect the valve body TCC apply valve for sticking
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Check for wiring shorts keeping the solenoid powered
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A stuck-on TCC acts like driving a manual car in gear without pressing the clutch
Frequently Asked Questions
Can I drive with code P0742?
Do not drive -- have the vehicle towed. Torque Converter Clutch Circuit Stuck On can cause severe transmission damage if ignored.
What is the most common fix for P0742?
The most common fix is replacing the affected solenoid. In some cases, a transmission fluid flush and solenoid replacement resolves the issue. Internal torque converter or valve body damage requires more extensive repair.
Can I replace the solenoid myself?
On some vehicles, shift solenoids are accessible by removing the transmission pan. On others, the valve body must be removed. This is a moderate to hard DIY job requiring transmission fluid drainage and careful reassembly.