What it means
The input/turbine shaft speed sensor A circuit signal is above the expected range.
At a glance
- Usually lights the check-engine light
How it works
Input/turbine shaft speed sensor A measures transmission input-shaft speed for shift control. This code sets when its circuit signal rises above the expected high-side range, such as when the signal is shorted toward a voltage source.
Common causes
Most likely first.
- Signal wire shorted to reference voltage
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Read freeze-frame and live data to check sensor A speed and identify when its signal went high relative to engine speed and gear changes.
- Inspect sensor A's connector and harness for pinched insulation, corrosion, loose pins, or contact with a power source.
- Use the wiring diagram to check the sensor A signal for a short to reference voltage or battery voltage and verify the circuit connections.
- Check whether sensor A produces a plausible changing reading as the input shaft turns, following the vehicle's service procedure.
- If the harness is sound, test sensor A and the module input against the manufacturer's specification.
Common fixes
- Reseat or clean sensor A's connector if its contacts are poor.
- Repair a signal wire shorted to reference voltage or battery power.
- Replace damaged or pinched wiring at sensor A.
- Replace input/turbine shaft speed sensor A if its output remains high.
- Repair the transmission control module input circuit if testing isolates the fault there.
Can I keep driving?
Limit driving if the transmission shifts harshly, slips, or behaves unpredictably; avoid towing or heavy loads. Continued driving with unreliable input-speed data can worsen transmission damage, so arrange a tow if safe shifting is not maintained.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.