What it means
The position sensor that confirms the park pawl A engagement state reads below the lower diagnostic threshold. Without confirmed park engagement the shift-by-wire controller cannot release the brake hold.
At a glance
- Usually lights the check-engine light
How it works
Park pawl position sensor A reports whether the transmission's mechanical pawl is engaged in Park. The shift-by-wire controller checks sensor A's signal to confirm the pawl state before allowing related shift or brake-hold actions. P271A sets when that signal falls below the diagnostic threshold, which can be caused by a shorted sensor or signal wire.
Common causes
Most likely first.
- Internal short in sensor element
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
Symptoms
- Transmission or gear-selection warning light may be on
- Park may not be recognized or confirmed
- Vehicle may not shift out of Park
How to diagnose it
- Save freeze-frame data and use live data to compare park pawl sensor A's reported state with the selected gear and the actual Park indication.
- Inspect sensor A's connector and harness for corrosion, pin damage, fluid, or a signal wire rubbed against ground.
- Check the sensor A signal and reference circuit using the manufacturer's wiring diagram and test procedure.
- Test sensor A for an internal short according to the manufacturer's procedure.
- If the sensor and wiring test correctly, investigate the shift-by-wire controller and pawl-position mechanism for an interpretation or mechanical fault.
Common fixes
- Repair a signal wire shorted to ground.
- Clean or repair corroded connector pins at park pawl sensor A.
- Replace sensor A if it has an internal short.
- Repair the pawl-position mechanism or controller only if tests identify a fault there.
Can I keep driving?
Do not rely on the vehicle being secured in Park unless the vehicle confirms Park and remains stationary; use the parking brake on level ground. If it will not shift out of Park or Park cannot be confirmed, avoid driving and arrange service.
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.