What it means
The TCM has not learned the calibration window for transmission range sensor A. Selector positions cannot be mapped reliably until adaptation completes.
At a glance
- Usually lights the check-engine light
How it works
Transmission range sensor A reports selector position information that the transmission control module uses to identify the selected range. This code sets when the module has not learned the calibration window for sensor A, so it cannot reliably map that sensor’s readings to selector positions.
Common causes
Most likely first.
- Range sensor or related component replaced without completing its learn procedure
- Learn procedure interrupted or unsuccessful
- Range sensor wiring, connector, or adjustment fault
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
- Review freeze-frame and module history to determine whether the fault appeared after range sensor A or a related component was replaced or adjusted.
- Check live range-sensor A data while moving the selector through its positions and note readings that are missing, unstable, or inconsistent with the selected range.
- Inspect sensor A’s connector and wiring for corrosion, loose pins, damage, or signs that the sensor or linkage has shifted.
- Verify range sensor A’s installation and adjustment using the manufacturer's procedure before attempting a learn.
- If the sensor readings are stable and installation is correct, complete the manufacturer's sensor A learn procedure and confirm that the code does not return.
Common fixes
- Complete the manufacturer's transmission range sensor A learn procedure if replacement or service left calibration incomplete.
- Reconnect or repair damaged wiring and connector pins for sensor A.
- Adjust or reinstall range sensor A according to the manufacturer's procedure.
- Replace sensor A if its readings remain unreliable after wiring and adjustment checks.
Can I keep driving?
Drive only if the selected range is recognized correctly and the transmission shifts predictably; avoid busy traffic or steep routes if shifts are delayed or missing. If the vehicle selects the wrong range, slips, or becomes stuck in one gear, stop safely and arrange diagnosis.
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.