What does it mean?
B1457 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Side Impact Sensor (Rear: LH) Power Supply Circuit System .
Symptoms
- Airbag/SRS warning lamp illuminated
- Rear left side impact detection is out of service, so the side and curtain airbags on that side are inhibited
- Fault may be intermittent and set mainly on rough roads or during engine cranking
- Other SRS codes for the same sensor branch are often stored at the same time
- Code may clear briefly and then return after a heavy door slam or a bump
Likely causes
- Open or high-resistance joint in the supply wire between the control unit and the rear left sensor
- Corroded or loose terminal in the sensor connector or in an intermediate body connector
- Wire broken where the loom passes under the sill trim, through a seat mounting or into the rear quarter
- Sensor drawing excessive current internally and pulling its own supply down
- Poor ground reference for the sensor, which shifts the measured supply level
- Failed supply driver inside the airbag control unit
- Weak vehicle battery or a bad main SRS feed causing a borderline supply during cranking
How to fix it
- Read all SRS codes and record which are current, which are historic and what the freeze frame shows
- Confirm battery condition and charging voltage first, since a weak supply can set marginal SRS codes
- Power down: ignition off, battery disconnected, prescribed wait time observed, before opening any connector
- Open the sensor connector and inspect for corrosion, spread terminals and a loose crimp on the supply wire
- Measure the resistance of the supply wire from the airbag control unit connector to the sensor connector and compare against a near-zero expectation
- Do a wiggle test along the sill and rear quarter route while watching the reading for a break that opens under movement
- Repair or replace the damaged loom section and clean up every ground point in the SRS circuit
- Replace the sensor only if the supply line measures correct at the sensor end, then clear the codes and verify with an ignition cycle and a road test