What it means
The position sensor or switch of transmission range control channel A reports a circuit range/performance condition. The TCM cannot verify the actuator position reliably.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The transmission range control A position sensor or switch reports the position of the A-channel mechanism to the transmission control module. This code sets when the signal is present but outside the expected range or does not track position changes properly.
Common causes
Most likely first.
- Dirty or oxidised switch contacts
- Sensor mounting misadjusted
- Sensor element aged beyond calibration window
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
- Save freeze-frame data and monitor commanded range and A-channel position live data while selecting the available ranges with the vehicle safely secured.
- Check whether the reported A position changes smoothly and agrees with the selected range, noting any mismatch or dropout.
- Inspect the A sensor or switch mounting and connector for misalignment, contamination, corrosion, or loose terminals.
- Check the switch contacts or sensor signal for erratic output and compare results with the manufacturer's specification.
- If the signal remains out of range, verify sensor adjustment and wiring integrity using the vehicle wiring diagram and manufacturer's procedure.
Common fixes
- Clean and secure oxidized A-channel switch contacts and connector terminals.
- Adjust the A position sensor mounting according to the manufacturer's procedure.
- Replace the A sensor if its output remains outside the calibration range.
- Clear the code and verify that A-channel readings follow each selected range.
Can I keep driving?
Avoid driving if the A position reading disagrees with the selected range, shifting is harsh or delayed, or limp mode is active; the transmission may engage unpredictably. If operation seems normal, restrict driving and avoid heavy loads until the sensor signal is checked.
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.