P0742 Torque Converter Clutch Circuit Stuck On

P0742 indicates the torque converter clutch circuit is stuck on. The converter clutch appears applied when the controller expects it to release.

Code details

Generic OBD-II · P0

System: Transmission
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not keep driving if the converter clutch remains applied at stops; it can cause stalling and additional transmission damage.

Symptoms of P0742

Harsh, delayed, or slipping shifts, or being stuck in one gear.
Check-engine light, sometimes with limp-home mode.
Flaring RPM or a shudder under load.

Common causes of P0742

Low or degraded transmission fluid.
A failing speed sensor, shift solenoid, or pressure-control circuit.
Wiring, connector, or internal hydraulic/mechanical faults.

Useful checks before replacing parts

Watch TCC command, TCC slip, engine RPM, turbine speed, and vehicle speed during decel, idle, and light throttle.
Check for a stuck TCC solenoid, valve-body issue, wiring fault, contaminated fluid, or pressure-control problem.
Review stall, shudder, or engine-stalling symptoms when coming to a stop.

Related OBD-II codes

These nearby transmission entries can help compare wording and pin down the fault area.