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P0720 — Output speed sensor circuit erratic
SerioustransmissionPower derate likely — plan to stop soon
Seen on: Output shaft speed
Output speed sensor circuit erratic. Common causes: Sensor|Tone wheel|Air gap|Wire rub.
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
- Sensor
- Tone wheel
- Air gap
- Wire rub
First moves (roadside)
- Inspect sensor air gap
- Tone wheel condition
FAQ
What does P0720 mean?
Output speed sensor circuit erratic. Common causes: Sensor|Tone wheel|Air gap|Wire rub.
How serious is P0720?
Serious — Power derate likely — plan to stop soon.
What's the most likely cause of P0720?
The most common cause is: Sensor. Other possibilities include Tone wheel; Air gap; Wire rub.
Can I keep driving with P0720?
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.