Start-Stop 12V Battery State of Health Below Threshold
2006-2011 BMW 325i 3.0L I6 N52
Description
The 12V AGM or EFB battery state of health has degraded below the minimum threshold required for reliable start-stop operation.
Symptoms
- Start-stop permanently disabled
- Battery management warning
- 12V battery struggles in cold weather
- Electrical systems may exhibit issues
- Start-stop light always off
- Higher fuel consumption without start-stop
Common Causes
- Battery age exceeding service life
- Excessive parasitic draw degrading battery
- Battery not properly maintained
- Wrong battery type installed (non-AGM/EFB)
- Frequent short trips not fully recharging battery
Diagnostic Steps
- Read battery state of health via IBS/BMS
- Load test 12V battery
- Check battery type matches vehicle specification
- Test charging system output
- Measure parasitic draw
Repair Notes
Replace 12V battery with correct AGM or EFB specification. Register new battery with vehicle BMS. Standard flooded batteries are not suitable for start-stop vehicles.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P3606 on Other Vehicles
Common Questions
What does code P3606 mean on a 2006-2011 BMW 325i?
P3606 stands for "Start-Stop 12V Battery State of Health Below Threshold". The 12V AGM or EFB battery state of health has degraded below the minimum threshold required for reliable start-stop operation.
What are the symptoms of P3606 on a BMW 325i?
Common symptoms of P3606 include: Start-stop permanently disabled, Battery management warning, 12V battery struggles in cold weather, Electrical systems may exhibit issues, Start-stop light always off, Higher fuel consumption without start-stop.
What causes P3606 on a 2006-2011 BMW 325i?
Common causes of P3606 include: Battery age exceeding service life, Excessive parasitic draw degrading battery, Battery not properly maintained, Wrong battery type installed (non-AGM/EFB), Frequent short trips not fully recharging battery.