P3807moderate severityPowertrain
48V System Energy Recovery Rate Low
on 2018 Mazda Mazda3 2.0L I4 · FWD
What this code means
The 48V mild hybrid system is not recovering the expected amount of kinetic energy during deceleration and coasting events.
Symptoms
- Mild hybrid efficiency reduced
- 48V battery SOC not recovering during driving
- Higher fuel consumption than expected
- Regenerative coasting function weak
- 48V charge indicator shows low recovery
Common causes
- BSG belt slip during regeneration
- 48V battery near full charge
- BSG inverter limiting regen current
- Drive belt tensioner weak
- 48V battery temperature too high or low for charging
Diagnostic steps
- Monitor 48V regen current during deceleration
- Check drive belt tension and condition
- Read 48V battery charge acceptance limits
- Check BSG inverter regen current capability
- Monitor 48V battery temperature during regen
Repair notes
Replace drive belt and tensioner if slipping. Address 48V battery temperature management. BSG replacement if regen output is low.
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