What it means
The input/turbine shaft speed sensor A circuit signal is below the expected range.
At a glance
- Usually lights the check-engine light
How it works
Input/turbine shaft speed sensor A reports how fast the transmission input shaft is turning so the control module can coordinate shifts. This code sets when sensor A's circuit signal is below the expected low-side range, often because the signal is being pulled toward ground.
Common causes
Most likely first.
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 transmission data to compare sensor A speed with engine speed and the operating conditions when the signal went low.
- Inspect sensor A's connector and harness for chafing, exposed conductors, corrosion, or loose pins that could short the signal to ground.
- Using the wiring diagram, check the sensor A signal wire for a short to ground and inspect its supply and ground connections.
- Check whether the sensor A reading responds as the input shaft turns, using the vehicle's supported scan data or test procedure.
- If the wiring is intact, test sensor A and the control module input against the manufacturer's specification.
Common fixes
- Reconnect or clean sensor A's connector if contact is poor.
- Repair chafed wiring or a signal wire shorted to ground.
- Restore a damaged sensor A supply or ground connection.
- Replace input/turbine shaft speed sensor A if its output is faulty.
- Repair the transmission control module input circuit if the sensor and wiring pass testing.
Can I keep driving?
Avoid towing or hauling and limit driving if shifts are harsh, delayed, or the transmission slips. Stop and arrange a tow if it enters a fixed gear or loses predictable shifting, as continued operation can cause damage.
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.