P07B8
Transmission Park Position Sensor/Switch B Circuit/Open
Park position sensor/switch B is the redundant/secondary park-confirmation sensor — used in shift-by-wire systems for safety, so a single sensor failure cannot strand the vehicle in Park or hide a non-Park condition. With B open the TCM falls back to sensor A only.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- Open wire or unplugged sensorCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Park Position Sensor B
- Wiring Harness
P07B8 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.