Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Code P0740, TCC Circuit: Notes
Control module monitors difference between engine speed and transaxle input shaft speed. With selector in D3 or D4 (indicated gear 3 or 4) and TCC locked, scan should display engine speed closely matching input speed. PWM solenoid is used to vary hydraulic pressure to converter clutch regulator valve which causes a smooth TCC engagement.
Code 740 will set when vehicle is in 3rd or 4th gear and, brake not applied, TCC is commanded by control module and engine speed-to-vehicle speed ratio does not indicate TCC has engaged. All these conditions must have been met for more than 10 seconds.
- Checks if fault is caused by a bad solenoid or control circuit.
- Tests fuse, brake switch, battery power circuits to transaxle connector.
- Checks control module's ability to pulse PWM solenoid.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.