What does it mean?
B1397 is a Body (airbags, seat belts, body electronics) fault code. It indicates: STPS (Seat Track Position Sensor) - Driver Short or Short to Battery .
Symptoms
- SRS lamp on with a driver seat position circuit fault stored
- Scan tool value pegged at maximum and unresponsive to seat movement
- The fault may appear only while the seat heater or the power seat is being used
- Airbag deployment force reverts to its default rather than adapting to the driver position
- No change in engine or driving behaviour
Likely causes
- Signal wire chafed onto a powered driver seat circuit such as the seat heater or memory seat motor feed
- Aftermarket under-seat wiring for a heater pad, amplifier or accessory laid alongside the sensor circuit
- Signal and supply wires shorted together inside a crushed section of the under-seat loom
- Water in the seat connector bridging the signal pin to a live pin
- Terminal pushed back in a shared connector body and touching a powered contact
- Sensor failed internally with its output shorted to its supply
- Airbag control module input fault
How to fix it
- Check whether the fault comes and goes with a particular seat function, which identifies the circuit feeding the voltage
- Power the restraint system down safely and wait the specified discharge time
- Remove any aftermarket wiring installed under the driver seat alongside the sensor circuit
- Unplug the sensor, switch the ignition on and check the signal wire for battery voltage while operating the seat functions
- Inspect the loom along the rail and under the seat pan for a flattened section where insulation has failed
- Repair the damaged loom and reroute it away from powered seat wiring
- Replace the sensor after the harness tests clean, then confirm the value follows the seat smoothly