P271D

Code

Generic P — Powertrain

Park Pawl Position Sensor B Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 44 EN: 39 RU: 19

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Check Engine / Transmission fault lamp illuminated (MIL/TCM light)
DTC P271D set and stored in PCM/TCM
Incorrect or no Park detection by vehicle (Park indicator may be wrong)
Intermittent inability to shift into or out of Park or transmission interlock faults
Possible no-start condition on vehicles that require confirmed Park/Park Neutral position to start
Erratic transmission behavior related to park/neutral safety interlock

Obtain freeze frame and live data with a scan tool; confirm P271D active and check park pawl sensor B live value
Scan for related transmission and park/neutral switch codes
Visually inspect the park pawl sensor connector, wiring loom, and nearby harness for damage, chafing, corrosion or water intrusion
Back-probe the sensor connector and measure signal voltage with respect to ground at key positions (Park vs not-Park)
Measure reference voltage (often 5V) and ground at the sensor connector
Check continuity between sensor signal pin and PCM/TCM input pin; check for shorts to battery (B+) and to ground

Typical park pawl position sensor types: switched (on/off) or hall/position (0–5V). Expected reference: ~5.0 V (sensor reference) or battery depending on design
Normal signal range: approx. 0–5 V for most sensors. Park/active state often near 0 V or near reference voltage depending on sensor design
Circuit High definition: signal voltage above normal maximum (commonly >4.8–5.5 V) or approaching battery voltage (~12 V) indicating short to B+ or open internal pull-down
Open-circuit symptom: floating/high reading (may show battery voltage) when sensor is disconnected or internally open

Read and record DTCs, freeze frame and live data. Verify P271D is current (not historic) and note any simultaneous codes.
Attempt to reproduce fault while watching live data (cycle shifter through Park/Reverse/Drive) to see sensor B response.
Visually inspect connectors, pins and harness routing from the sensor to the PCM/TCM. Repair obvious damage or corrosion.
Back-probe the sensor connector: with ignition ON measure reference voltage, signal voltage, and ground. Compare to expected values in vehicle wiring diagram.
Measure signal voltage at the PCM/TCM input with connector connected; if signal is high at PCM and correct at sensor, suspect wiring between sensor and PCM.
Check continuity and resistance between sensor signal pin and PCM input pin with ignition OFF. Check for short to battery (signal to B+) and to ground.
If wiring checks good, swap or bench-test the sensor per service info (or measure sensor internal resistance/operation). Replace sensor if out of spec.
Repair any wiring/connector faults found (repair/replace harness, terminal repair, apply dielectric grease where appropriate).
Clear codes and retest by cycling shifter and driving as needed. If code returns and wiring/sensor are confirmed good, evaluate PCM/TCM input and replace control module only after confirming module fault with manufacturer procedures.
If electrical tests OK but sensor signal never changes with pawl movement, inspect park pawl mechanism for binding or mechanical failure and repair as required.