P3606moderate severityPowertrain
Start-Stop 12V Battery State of Health Below Threshold
on 2016 Mazda MX-5 Miata 2.0L I4 · RWD
What this code means
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.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1