P271C

Code

Generic P — Powertrain

Park Pawl Position Sensor B Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 36 RU: 23

AI status

Completed

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Page language: EN

Causes

Short to ground in park pawl position sensor B signal wire
Open or high-resistance connection in sensor wiring or connector
Corroded or damaged connector pins
Failed park pawl position sensor (Hall or switch element)
Faulty PCM/TCM input circuit
Mechanical problem preventing park pawl movement or proper sensor operation

Symptoms

DTC P271C stored and malfunction indicator lamp (MIL) may be illuminated
Vehicle may fail to stay in Park or show incorrect PRNDL indication
Transmission may not shift into or out of Park correctly
Intermittent inability to start (starter inhibited by park switch) or starter cranks in incorrect gear
Illumination of transmission-related warning lamp or messages

What to check

Retrieve freeze frame and live data with a scan tool (park pawl sensor B value, reference voltage, grounds)
Perform visual inspection of park pawl sensor connector and wiring for corrosion, damage, or loose pins
Check for other related transmission DTCs that may indicate broader wiring/PCM issues
Confirm whether code is current or historical and try clearing to see if it returns
Check battery voltage and charging system (low voltage can cause spurious low signals)

Signal parameters

Typical sensor reference: 5 V (check vehicle-specific spec)
Sensor ground: near 0 V (good chassis/PCM ground)
Sensor output: Hall/position sensors typically vary between ~0.2 V (low) and ~4.8 V (high) depending on position
P271C indicates output is below the expected low threshold (often
Expected resistance: if sensor is a switch it may read near 0 Ω closed / infinite open; if Hall effect, resistance is not a reliable measure—use voltage/pulse tests

Diagnostic algorithm

Read and record freeze frame and live data for park pawl position sensors A and B, reference voltage, and grounds. Note when the low condition occurs (park, shift, key on).
Visually inspect the park pawl position sensor B connector and wiring harness for damage, corrosion, pin push-out, or signs of fluid intrusion. Repair visual faults.
With ignition ON (engine off) backprobe the sensor connector: verify reference voltage (typically 5 V) and ground. If reference or ground missing, trace to PCM/TCM and repair.
Measure sensor B output voltage while moving the park pawl or shifting through gears (or commanded state). Confirm if output stays low. If output never changes and reference and ground are good, suspect sensor or short to ground.
Check continuity between sensor signal pin and the PCM/TCM input pin. Check for short to ground or short to 12 V using an ohmmeter with harness disconnected. Repair wiring as needed.
If wiring and connectors are good, substitute a known-good park pawl position sensor (if available) or bench-test the sensor per manufacturer procedure (signal output behavior/pulse with movement).
If sensor replacement does not clear the low condition, inspect mechanical park pawl assembly for binding or misalignment that might hold sensor in a low state or prevent movement.
If wiring, connector, sensor, and mechanical checks pass, test or replace the PCM/TCM input circuit as a last step or consult manufacturer resources—confirm PCM power/grounds and update software if applicable.
After repairs, clear codes and perform road test or gear-cycle to verify P271C does not return and that park pawl operation/PRNDL indications are normal.

Likely causes

Water intrusion/corrosion at park pawl connector
Connector pin pushed out or bent causing poor contact
Wiring rubbed through and grounded to chassis or transmission case
Sensor internal failure (shorted output to ground)
Loose or missing ground or reference feed to sensor

Fault status

⚠️ Status

Park pawl position sensor B circuit low — signal below expected threshold. Check sensor, wiring, connector, and module input for short to ground or open circuit.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours