P3801moderate severityPowertrain
48V Battery State of Charge Low
on 2017 Hyundai Tucson 2.0L I4 · FWD
What this code means
The 48V lithium-ion battery state of charge has dropped below the minimum threshold for mild hybrid functions.
Symptoms
- Mild hybrid boost disabled
- Start-stop disabled
- Increased engine load
- Regenerative braking not occurring
- 48V battery warning
- Higher fuel consumption
Common causes
- 48V battery degradation
- DC-DC converter not charging 48V battery
- Excessive 48V electrical loads
- 48V battery cell imbalance
- Extended vehicle storage without charging
Diagnostic steps
- Read 48V battery SOC and voltage
- Check 48V DC-DC converter output
- Monitor 48V charging during deceleration
- Test 48V battery health
- Check for excessive 48V parasitic draw
Repair notes
Allow vehicle to run and recharge 48V battery. If SOC does not recover, test 48V battery and DC-DC converter. Replace if degraded.
Other Powertrain codes on this vehicle
P0001
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P0002
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P0003
Fuel Volume Regulator Control Circuit Low
P0004
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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