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P codepowertrainHigh severity

P07BETransmission Park Position Sensor/Switch "A"/"B" Correlation

The transmission's two park position sensors disagree with each other, so the control module cannot confirm whether the transmission is actually in Park.

Definition

Shift-by-wire and electronically supervised transmissions use redundant park position sensing — sensors "A" and "B" — that must always agree on whether the park mechanism is engaged. P07BE sets when the two signals report conflicting states for longer than the allowed window, leaving the module unable to trust either reading. Because Park engagement cannot be verified, the vehicle may display persistent "Shift to Park" warnings, refuse to crank or power down and lock, automatically apply the electric park brake, or inhibit shifter functions; the underlying safety concern is a potential rollaway if Park is assumed but not actually engaged, so the vehicle should be secured with the park brake until repaired.

Common causes

  • One park position sensor failed or drifted while the other reads correctly
  • Connector corrosion, moisture, or terminal damage affecting one sensor circuit
  • Misadjusted, worn, or partially engaging park mechanism placing the sensors on opposite sides of their thresholds
  • Chafed or damaged harness wiring on one sensor circuit
  • Damaged shifter assembly or park actuator on shift-by-wire systems
  • Control module input fault (rare)

Common misdiagnoses

  • Replacing both sensors or the whole shifter when only one circuit has a wiring fault
  • Replacing the transmission range sensor for a park-sensor correlation code
  • TCM or PCM replacement before circuit testing
  • Internal transmission overhaul for an external sensor or adjustment issue
  • Electric park brake service because the failsafe keeps applying it

Troubleshooting steps

  1. 1.Secure the vehicle first

    Apply the parking brake and chock a wheel during diagnosis, since the module cannot verify Park engagement while this code is active.

  2. 2.Compare both sensor signals

    View park sensors "A" and "B" live while cycling Park to Drive, identifying which one fails to change state or reads opposite the commanded position.

  3. 3.Check for companion codes

    A circuit code for one specific sensor (such as P07BC or P07BD) alongside the correlation fault points directly at that sensor's circuit.

  4. 4.Inspect connectors and harness

    Examine the shifter and transmission connectors for corrosion, water intrusion, and terminal damage, and wiggle-test while watching the mismatching signal.

  5. 5.Verify park mechanism travel

    Confirm the park actuator or linkage fully engages the pawl, since partial travel can legitimately split the two sensors' readings.

  6. 6.Replace the faulted sensor

    Replace the sensor or sensor/shifter unit identified as wrong, then confirm both signals agree through repeated Park cycles before returning the vehicle.

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