48V System Isolation Fault
2016-2020 Kia Optima 2.4L I4
Description
The 48V electrical system isolation monitoring has detected reduced insulation resistance between the 48V bus and vehicle chassis.
Symptoms
- 48V system may be disabled
- Mild hybrid functions lost
- Warning indicator illuminated
- Potential electrical shock risk
- System enters safe mode
Common Causes
- Moisture in 48V connector
- Damaged 48V cable insulation
- 48V battery case leak
- Component insulation breakdown
- Wiring chafed against chassis
Diagnostic Steps
- Read 48V isolation resistance value
- Perform 48V isolation test per segment
- Inspect 48V wiring for damage
- Check 48V connectors for moisture
- Test 48V battery case integrity
Repair Notes
Locate and repair source of isolation loss. While 48V is below lethal threshold, it can cause burns and arcing. Repair promptly.
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
P3804 on Other Vehicles
Common Questions
What does code P3804 mean on a 2016-2020 Kia Optima?
P3804 stands for "48V System Isolation Fault". The 48V electrical system isolation monitoring has detected reduced insulation resistance between the 48V bus and vehicle chassis.
What are the symptoms of P3804 on a Kia Optima?
Common symptoms of P3804 include: 48V system may be disabled, Mild hybrid functions lost, Warning indicator illuminated, Potential electrical shock risk, System enters safe mode.
What causes P3804 on a 2016-2020 Kia Optima?
Common causes of P3804 include: Moisture in 48V connector, Damaged 48V cable insulation, 48V battery case leak, Component insulation breakdown, Wiring chafed against chassis.