Hood Ajar Switch Circuit
2008-2008 Cadillac STS 3.6L V6
The 2008 Cadillac STS is equipped with a 3.6L V6 engine. Below you'll find detailed b0123 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
Malfunction in the hood ajar switch circuit used by the theft deterrent system and vehicle status monitoring.
Symptoms
- Hood ajar warning always on or off
- Theft system does not detect hood opening
- Interior lights triggered by phantom hood open
Common Causes
- Faulty hood switch
- Switch out of adjustment
- Wiring damage in engine bay
- Corroded switch from engine bay moisture
Diagnostic Steps
- Check hood switch alignment
- Test switch continuity
- Inspect wiring
- Clean or adjust switch
- Test circuit voltage at BCM
Repair Notes
Adjust or replace hood ajar switch. Protect wiring from engine bay heat and moisture.
Related Codes
Other Body Codes
- B0001Driver Frontal Stage 1 Deployment Control
- B0002Driver Frontal Stage 2 Deployment Control
- B0003Passenger Frontal Stage 1 Deployment Control
- B0004Passenger Frontal Stage 2 Deployment Control
- B0005Driver Knee Airbag Deployment Circuit
- B0006Passenger Knee Airbag Deployment Circuit
- B0007Rear Left Side Airbag Deployment Circuit
- B0008Rear Right Side Airbag Deployment Circuit
- B0010Driver Side Airbag Deployment
- B0011Driver Side Airbag Deployment Circuit Open
B0123 on Other Vehicles
Common Questions
What does code B0123 mean on a 2008-2008 Cadillac STS?
B0123 stands for "Hood Ajar Switch Circuit". Malfunction in the hood ajar switch circuit used by the theft deterrent system and vehicle status monitoring.
What are the symptoms of B0123 on a Cadillac STS?
Common symptoms of B0123 include: Hood ajar warning always on or off, Theft system does not detect hood opening, Interior lights triggered by phantom hood open.
What causes B0123 on a 2008-2008 Cadillac STS?
Common causes of B0123 include: Faulty hood switch, Switch out of adjustment, Wiring damage in engine bay, Corroded switch from engine bay moisture.
Last updated: March 2026