B0039critical severityBody
Front Impact Severity Sensor Circuit
on 2021 Mazda Mazda3 2.5L Turbo I4 · FWD
What this code means
Malfunction in the frontal impact severity sensor used to determine airbag deployment force level.
Symptoms
- Airbag warning light on
- SRS fault stored
- Dual-stage airbag staging may be incorrect
Common causes
- Faulty severity sensor
- Wiring damage
- Control module fault
- Sensor mounting compromised
Diagnostic steps
- Scan SRS codes
- Inspect severity sensor
- Check wiring to ACM
- Measure sensor circuit
- Verify sensor mounting
Repair notes
Replace impact severity sensor. Ensure correct deployment staging by verifying ACM calibration.
Other Body codes on this vehicle
B0001
Driver Frontal Stage 1 Deployment Control
B0002
Driver Frontal Stage 2 Deployment Control
B0003
Passenger Frontal Stage 1 Deployment Control
B0004
Passenger Frontal Stage 2 Deployment Control
B0005
Driver Knee Airbag Deployment Circuit
B0006
Passenger Knee Airbag Deployment Circuit
B0007
Rear Left Side Airbag Deployment Circuit
B0008
Rear Right Side Airbag Deployment Circuit
B0009
Rear Center Airbag Deployment Circuit
B0010
Driver Side Airbag Deployment