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DTC codes / P07xx · Transmission / P07B6

P07B6Transmission Park Position Sensor/Switch A Circuit Performance High

P07B6 means the transmission control module (TCM) has detected an implausible high signal from the park position sensor or switch A circuit, indicating the voltage or position reading is outside the expected range for the current gear state. The computer compares the park switch signal with other range sensors and sees a performance fault rather than a simple open or short.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • The gear position indicator may show the wrong range or flash intermittently.
  • The vehicle may fail to start because the TCM does not recognize park or neutral.
  • A warning light or message such as 'Transmission Range Sensor' appears on the dash.
  • The transmission may hesitate or refuse to engage drive or reverse from park.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.
  • Remote start or keyless ignition may be disabled due to the park signal uncertainty.

Common causes, most likely first

  1. A faulty park position sensor or switch internal to the transmission range sensor assembly.
  2. Damaged, chafed, or corroded wiring in the park switch A circuit, often near the transmission connector.
  3. A poor electrical ground or reference voltage at the TCM or sensor connector.
  4. Water or fluid intrusion into the sensor connector causing high resistance or intermittent shorts.
  5. A misadjusted or loose transmission range sensor mounting bracket.
  6. A failing transmission control module (TCM) or internal TCM fault, though less common.
  7. Aftermarket or incorrect replacement sensor not matching the vehicle's calibration.

How to diagnose and fix it

  1. Use a scan tool to read live data for the park position sensor and compare it with the gear selector position.
  2. Inspect the transmission range sensor connector and wiring for corrosion, chafing, or loose pins.
  3. Check the sensor's reference voltage and ground at the connector with a multimeter.
  4. Perform a wiggle test on the harness while watching live data to catch intermittent faults.
  5. Follow the manufacturer's procedure to adjust or replace the transmission range sensor if the signal is erratic.
  6. Clear the code and test-drive through all gear ranges to confirm the repair.
  7. If the fault persists, check TCM software updates or internal TCM faults before replacement.

Park switch faults that fool good technicians

  • A park position sensor can pass a simple resistance test yet still set P07B6 because the TCM monitors signal timing and plausibility, not just continuity.
  • Wiring harness damage near the transmission mount or under the battery tray is a common hidden cause that looks like a sensor failure.
  • Some vehicles use the park switch signal for starter enable, so a no-crank complaint may be misdiagnosed as a starter problem when P07B6 is stored.
  • After replacing a transmission range sensor, the TCM often requires a relearn or calibration procedure, and skipping it can cause the code to return immediately.
  • Intermittent P07B6 codes are frequently caused by water intrusion into the connector after pressure washing or deep water fording, not by a failed sensor.

Can I keep driving with P07B6?

If the vehicle starts and drives normally, you can drive cautiously to a repair shop, but avoid relying on remote start or keyless entry features. If the vehicle will not start or the transmission will not engage, do not continue driving and arrange for a tow.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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