B1000 B0xxx · Body (B) Medium severity
Body Control Module Internal Fault
A generic body-module self-check failure. Manufacturer-specific above the SAE range — read the module's own extended data before acting.
Severity guidance: Medium — drivability or emissions affected, book it in this week
Symptoms you will notice
- Multiple body functions out
- Lighting, locking or windows behaving oddly
- Scan tool communication problems
Common causes
Ordered from most to least likely — start at the top.
- 1 Software or configuration fault
- 2 Power supply or earth problem
- 3 Water ingress in the module
- 4 True hardware failure (least common)
How to diagnose it
Cheapest and least invasive first — most of these codes are not a parts problem.
- ✓ Check battery voltage, fuses and all body-module earths first.
- ✓ Inspect the module and its connectors for water damage.
- ✓ Check whether coding/configuration was lost after a battery disconnect.
- ✓ Look for a software update before replacing hardware.
Repair options
- Repair power or water-ingress faults and reconfigure
- Reflash or replace the module as a last resort
B1000 — frequently asked questions
Is the module dead? +
Rarely. Most of these are power, earth or water problems that disappear once the supply is restored.
Can a flat battery cause it? +
Yes — low voltage during cranking corrupts configuration and sets internal faults.
Confirm the diagnosis before you buy parts
Send us the code, freeze-frame data and the vehicle — our engineers will tell you what to test first.