P271A: Park Pawl Position Sensor A Circuit Low

With park-by-wire the pawl is moved by an actuator instead of a cable, and a position sensor tells the controller whether it is engaged. P271A means the signal of sensor A has dropped below its valid band. Ford's 2026 safety recall 26V688 shows a real case: on 2026-2027 Lincoln Nautilus Hybrid and 2027 Corsair Hybrid with the HF55 hybrid transmission, an unvalidated anti-rust oil inside the Integrated Park Module attacked the circuit board coating, the rotary sensor circuit corroded and its output voltage sank. Dealers found P271A. Owners saw a wrench lamp with Service Vehicle Soon or Shifting System Error, could not leave Park, or the car shifted to Neutral while moving. The fix is a new module with current software.

Symptoms

• Vehicle cannot be shifted out of Park
• Unexpected shift to Neutral while driving
• Service warning such as Shifting System Error

Most likely causes

• Corrosion on the park module circuit board (Ford HF55, recall 26V688)
• Sensor A signal wire shorted to ground
• Missing or low reference voltage to sensor A
• Failed position sensor A

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the fluid level and condition
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Read the input and output speed in live data
4. Check the connector and wiring
5. Check for other related engine codes
6. Consult the manufacturer's procedure for the transmission

Good to know

• It can trigger limp mode.

What each character of P271A means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 7: Transmission
• 1A: Specific fault in that system

Frequently asked questions

Can I keep driving with code P271A?

Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.

What causes code P271A?

The most common causes are: corrosion on the park module circuit board (Ford HF55, recall 26V688); sensor A signal wire shorted to ground; missing or low reference voltage to sensor A.

Related codes

• P271BPark Pawl Position Sensor A Circuit High
• P271CPark Pawl Position Sensor B Circuit Low
• P271DPark Pawl Position Sensor B Circuit High
• P272CPark Pawl Motor Control Circuit
• P07B5Transmission Park Position Sensor/Switch A Circuit Performance/Low

Sources

• static.nhtsa.gov: RCLRPT 26V688 0857
• en.wikipedia.org: Shift by wire
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.