What does it mean?
B1388 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver Seat Track Position Sensor Open or Short to Power .
Symptoms
- SRS lamp on with a seat position fault stored
- The reading is stuck at its maximum or shown as out of range on the scan tool
- Airbag deployment force reverts to its fixed default instead of adapting to how far forward the driver sits
- The fault often sets during a seat adjustment or right after under-seat work
- Nothing changes in how the vehicle drives
Likely causes
- Sensor connector under the driver seat left unplugged or half-latched after seat, carpet or interior work
- Open circuit in the sensor signal wire where the under-seat loom flexes with seat travel
- Signal wire chafed onto a powered seat circuit such as the heater or seat motor feed
- Sensor element internally open
- Corroded or pushed-back terminal at the sensor or at the module plug
- Loss of the sensor ground, which the module also reads as an out of range high signal
- Airbag control module input fault
How to fix it
- Look at the live seat track position value first; a value pegged high supports an open or a short to power
- Power the restraint system down safely and observe the reserve power discharge time
- Check that the sensor connector under the seat is fully latched and that no terminal has backed out
- Measure the signal wire for continuity from sensor to module, and check the sensor ground for a clean connection
- With the sensor unplugged, check the signal wire for voltage with the ignition on to rule out a short to power
- Move the seat through its full travel while monitoring, to catch a break that only opens at one end of the rail
- Replace the sensor after the wiring, connector and ground are proven good, then verify the value changes smoothly with seat position