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P0740 — Torque converter clutch solenoid circuit
SerioustransmissionPower derate likely — plan to stop soon
Torque converter clutch solenoid circuit. Common causes: TCC solenoid|Wiring|Lockup issue.
Don't risk it — get a diesel tech on the truck.
Look up listed providers near you and give them this code when you call.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- TCC solenoid
- Wiring
- Lockup issue
First moves (roadside)
- Solenoid resistance
- Drive wire
FAQ
What does P0740 mean?
Torque converter clutch solenoid circuit. Common causes: TCC solenoid|Wiring|Lockup issue.
How serious is P0740?
Serious — Power derate likely — plan to stop soon.
What's the most likely cause of P0740?
The most common cause is: TCC solenoid. Other possibilities include Wiring; Lockup issue.
Can I keep driving with P0740?
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Throwing this code right now?
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.