BCM reduced power to accessories to protect battery — often precedes no-crank if ignored.
Common symptoms
- Accessories shut off
- Slow crank later
- Battery warning
Typical causes
- Weak battery
- Parasitic drain
- Alternator not charging
- Extended key-on engine off
What scanner do you need?
Full-system scanner (engine, ABS, SRS, transmission, service resets)
Use live data and freeze frame to confirm the fault before replacing parts. ABS, SRS, and network U-codes usually require a full-system scanner.
Diagnostic tips
- Record freeze frame data when the code first sets
- Clear the code only after fixing the root cause
- Check for related pending codes that point to a common issue
- Verify battery voltage is above 12.4V before chasing sensor codes