P0718: Input/Turbine Speed Sensor "A" Circuit Intermittent
The input (turbine) speed signal drops out for short moments.
High risk
Drive gently and have it checked soon; the transmission may shift harshly or stay in one gear.
Short answer · Can I keep driving with P0718?
Only gently. Shifts may be harsh now and then, or the transmission may hold one gear. Have the sensor and wiring checked soon.
What does P0718 mean?
Code P0718 means pulses from the input speed sensor are sometimes missing. A loose or corroded connector, a chafed wire or a sensor that fails when hot are typical causes.
What the car does when the code is set
The check engine or transmission warning comes on. Shifts may be harsh or late, the transmission may hold one gear, and the speedometer may show wrong values on some cars.
How the system works
An automatic transmission uses speed sensors to compare the turbine (input) speed with the output speed. From the ratio, the transmission control unit knows which gear is engaged, whether a clutch is slipping and how to time shifts smoothly. The input speed sensor reads a toothed wheel on the input shaft or a clutch drum. If its signal disappears or does not fit the engine and output speeds, the control unit stores a code and often switches to a fixed gear.
Common symptoms
Possible causes
Listed without ranking. The cause on your car depends on make, engine and mileage — see the maker notes below.
- Faulty input speed sensorThe sensor fails or its signal is weak.
- Wiring or connector faultOften at the transmission connector.
- Metal debrisDebris on a magnetic sensor.
- Transmission control unit faultLess common.
How it is diagnosed
- Read live dataCompare input speed with engine speed in a fixed gear.
- Check wiring and connectorsLook for fluid in the connector and damaged wiring.
- Measure the sensorCheck resistance or signal as in the service data.
- Check the fluidDebris in the fluid points to internal wear.
Questions about P0718
Why does the fault come and go?
Intermittent faults often depend on heat or vibration. Moving the wiring gently while watching live data can show where the contact is lost.
Can low fluid cause sensor codes?
Sometimes. Low fluid can make the gearbox behave abnormally. Check the fluid as part of the diagnosis.
Can I drive in limp mode?
Only short distances. Limp mode usually keeps one gear for safety.