Generator Output Voltage No Output
2014-2021 Mazda Mazda6 2.5L I4
Description
The PCM has detected that the generator (alternator) is producing no output voltage. The charging system is not maintaining battery charge, and the vehicle is running solely on battery power.
Symptoms
- Check Engine Light
- Battery warning light on
- Battery draining
- Electrical systems losing power
- Vehicle will eventually stall
Common Causes
- Failed alternator (diode pack or rotor)
- Broken or slipping serpentine belt
- Disconnected alternator wiring
- Blown alternator fuse or fusible link
- Faulty voltage regulator
Diagnostic Steps
- Measure charging voltage at battery with engine running (should be 13.5-14.8V)
- Inspect serpentine belt condition and tension
- Check alternator wiring connections
- Test alternator output with load tester
- Check alternator fuse and fusible links
Repair Notes
Replace the alternator if it has no output; check belt and wiring first.
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
P1631 on Other Vehicles
Common Questions
What does code P1631 mean on a 2014-2021 Mazda Mazda6?
P1631 stands for "Generator Output Voltage No Output". The PCM has detected that the generator (alternator) is producing no output voltage. The charging system is not maintaining battery charge, and the vehicle is running solely on battery power.
What are the symptoms of P1631 on a Mazda Mazda6?
Common symptoms of P1631 include: Check Engine Light, Battery warning light on, Battery draining, Electrical systems losing power, Vehicle will eventually stall.
What causes P1631 on a 2014-2021 Mazda Mazda6?
Common causes of P1631 include: Failed alternator (diode pack or rotor), Broken or slipping serpentine belt, Disconnected alternator wiring, Blown alternator fuse or fusible link, Faulty voltage regulator.