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P0742 — TCC stuck on
SerioustransmissionPower derate likely — plan to stop soon
TCC stuck on. Common causes: Failed TCC|Stuck solenoid|Valve body.
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
- Failed TCC
- Stuck solenoid
- Valve body
First moves (roadside)
- Solenoid and valve body
FAQ
What does P0742 mean?
TCC stuck on. Common causes: Failed TCC|Stuck solenoid|Valve body.
How serious is P0742?
Serious — Power derate likely — plan to stop soon.
What's the most likely cause of P0742?
The most common cause is: Failed TCC. Other possibilities include Stuck solenoid; Valve body.
Can I keep driving with P0742?
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.