What it means
The position sensor or switch of transmission range control channel A reports a circuit high 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 tells the transmission control module the position of the A-channel mechanism. This code sets when the signal voltage is higher than expected, so the module cannot reliably verify that position.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open position sensor
- Connector pins corroded - high contact resistance
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 inspect live data for commanded range and A-channel position to establish when the high signal occurs.
- Compare the range selected at the shifter with the range the transmission module reports.
- Inspect the A sensor connector and wiring for corrosion, an open sensor connection, loose pins, or a signal wire touching battery voltage.
- Test the A sensor signal wire for a short to battery voltage and check connector continuity using the vehicle wiring diagram.
- Check the A position sensor or switch output against the manufacturer's specification to determine whether the sensor itself is open.
Common fixes
- Clean and secure corroded or loose A-channel connector terminals.
- Repair the A signal wire if it is shorted to battery voltage.
- Replace the A position sensor if it is internally open.
- Clear the code and verify that A-channel position data tracks the selected range.
Can I keep driving?
Do not continue driving if the transmission fails to recognize the selected range, slips, or enters limp mode; unreliable gear engagement can create a hazard and increase damage. If shifts remain normal, keep driving to a minimum until diagnosed.
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.