P2504critical severityPowertrain
Charging System Voltage High
on 2021 Mazda MX-5 Miata 2.0L I4 · RWD
What this code means
Charging system output voltage exceeds maximum safe threshold.
Symptoms
- Battery boiling/swelling
- Bulbs burning out frequently
- Check engine light
- Electrical component damage
Common causes
- Failed voltage regulator
- ECM charging control fault
- Ground strap issue
Diagnostic steps
- Measure charging voltage at various RPM
- Check voltage regulator
- Inspect ground straps
Repair notes
Replace alternator or voltage regulator. Check and repair grounds. Overcharging can damage expensive electronics.
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