48V Belt Starter-Generator Performance
2012-2020 Ford Focus 2.0L I4 🇨🇦
Description
The belt-driven starter-generator (BSG) is not producing expected torque output for engine starting, boost assist, or energy recovery.
Symptoms
- Slow engine cranking
- No electric torque assist
- Weak regenerative braking
- Increased fuel consumption
- Belt squeal during start
- Vibration during BSG operation
Common Causes
- BSG internal fault
- Drive belt slip
- Belt tensioner wear
- BSG bearing failure
- Inverter module fault
Diagnostic Steps
- Check BSG torque output via scan tool
- Inspect drive belt condition and tension
- Listen for BSG bearing noise
- Test BSG inverter module
- Monitor BSG temperature during operation
Repair Notes
Replace BSG unit if internal fault confirmed. Replace drive belt and tensioner if slipping. BSG and belt are a common service item together.
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
P3802 on Other Vehicles
Ford Bronco
2021-2024 2.3L I4 EcoBoost
Ford Bronco
2021-2024 2.7L V6 EcoBoost
Ford Bronco Raptor
2022-2024 3.0L V6 EcoBoost
Ford Bronco Sport
2021-2024 1.5L I3 EcoBoost
Ford Bronco Sport
2021-2024 2.0L I4 EcoBoost
Ford E-350
1997-2024 6.8L V10 Triton
Ford E-350
2020-2024 7.3L V8 Godzilla
Ford Edge
2015-2018 2.0L I4 EcoBoost
Common Questions
What does code P3802 mean on a 2012-2020 Ford Focus?
P3802 stands for "48V Belt Starter-Generator Performance". The belt-driven starter-generator (BSG) is not producing expected torque output for engine starting, boost assist, or energy recovery.
What are the symptoms of P3802 on a Ford Focus?
Common symptoms of P3802 include: Slow engine cranking, No electric torque assist, Weak regenerative braking, Increased fuel consumption, Belt squeal during start, Vibration during BSG operation.
What causes P3802 on a 2012-2020 Ford Focus?
Common causes of P3802 include: BSG internal fault, Drive belt slip, Belt tensioner wear, BSG bearing failure, Inverter module fault.