48V Mild Hybrid Torque Assist Not Available
2019-2024 BMW 3 Series G20 2.0L I4 Turbo B48
Description
The 48V BSG system is unable to provide electric torque assist during acceleration events. The vehicle operates without hybrid boost.
Symptoms
- No electric assist during acceleration
- Slightly reduced off-the-line performance
- Increased fuel consumption
- Turbo lag more noticeable (if turbocharged)
- 48V system indicator may illuminate
Common Causes
- 48V battery SOC too low for assist
- BSG torque output limited by temperature
- 48V system in degraded mode
- Drive belt condition preventing torque transfer
- Control software limiting assist
Diagnostic Steps
- Check 48V battery SOC level
- Monitor BSG temperature
- Read 48V system inhibit reasons
- Inspect drive belt condition
- Review recent 48V system fault codes
Repair Notes
Resolve underlying 48V system issue. Charge 48V battery. Replace drive belt if worn. Address thermal issues.
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
P3806 on Other Vehicles
Common Questions
What does code P3806 mean on a 2019-2024 BMW 3 Series G20?
P3806 stands for "48V Mild Hybrid Torque Assist Not Available". The 48V BSG system is unable to provide electric torque assist during acceleration events. The vehicle operates without hybrid boost.
What are the symptoms of P3806 on a BMW 3 Series G20?
Common symptoms of P3806 include: No electric assist during acceleration, Slightly reduced off-the-line performance, Increased fuel consumption, Turbo lag more noticeable (if turbocharged), 48V system indicator may illuminate.
What causes P3806 on a 2019-2024 BMW 3 Series G20?
Common causes of P3806 include: 48V battery SOC too low for assist, BSG torque output limited by temperature, 48V system in degraded mode, Drive belt condition preventing torque transfer, Control software limiting assist.