P07BC
Transmission Park Position Sensor/Switch B Circuit Performance High.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- BC
- FaultThe specific fault in that area
What it means
P07BC is a generic transmission code meaning the control unit has judged the signal from Park position sensor/switch 'B' to be implausible, with the circuit reading high. The transmission or powertrain control unit compares this signal with other inputs, such as the selector position, the other park/neutral sensor, and vehicle speed. If they disagree, or the signal stays high when it should not, the code is set. How the sensor is built and what 'B' refers to varies by model and gearbox.
Symptoms
- Gearbox warning light or engine management light on
- Engine will not start, or starts in positions other than Park or Neutral
- Gear selector display in the dash shows the wrong position or flickers
- Reverse lights or shift interlock not working properly
- Harsh, delayed or no engagement when moving the selector
- Gearbox may go into a limited or fail-safe mode
Possible causes
- Faulty park position sensor/switch B, or an internal fault in the selector or range sensor assemblylikely
- Wiring damage, chafing, corrosion or poor terminal contact in the sensor circuit or connectorlikely
- Selector linkage or cable out of adjustment, so the sensor and the actual gear position do not matchpossible
- Water or fluid ingress into the sensor connector or gearbox harnesspossible
- Short to voltage, or a supply or ground fault, in the circuitpossible
- Fault in the transmission control unit or its software, including a known outdated calibrationrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, and note any other park, neutral, range or speed signal codes.
- Check that the selector position shown on the dash and in the scan data matches the lever position in each gear.
- Inspect the sensor wiring, connector and terminals for damage, corrosion, moisture, fluid and pin tension, and check the harness routing.
- Check the selector linkage or cable for wear, looseness and correct adjustment, following the manufacturer's procedure for the model.
- Watch the live data for park sensor A and B states while moving the selector through each position, and look for a signal that stays high or jumps.
- Check the supply voltage, ground and signal voltage at the sensor connector against the manufacturer's specification.
- Test the sensor or switch against the specified values for that gearbox, as these differ between models.
- Check for software updates or technical bulletins that cover this code for the vehicle.
How to fix
- Replace the faulty park position sensor/switch or selector assembly, and adjust it to specification if needed.
- Repair or replace damaged wiring, terminals or connectors, and seal out moisture.
- Adjust or repair the selector linkage or cable so the position matches the sensor.
- Clean up and dry any contaminated connectors, and fix the source of any fluid leak affecting them.
- Where the manufacturer identifies an outdated calibration as a cause, update the control unit software; replace the control unit only if testing confirms it has failed.
Can I keep driving?
The car may be driven short distances if it starts and the gearbox engages normally, but get it checked soon. If the car will not start or the selector position is not reliably detected, do not rely on the Park position alone: use the handbrake and have it repaired promptly.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.