P3444critical severityPowertrain
BMS High-Voltage Bus Pre-Charge Timeout
on 2010 Toyota Highlander 3.3L V6 Hybrid · AWD
What this code means
The BMS pre-charge sequence timed out before the HV bus voltage reached the target level.
Symptoms
- Vehicle will not enter Ready mode
- HV system fails to energize
- Clicking sounds from relay area
- Extended start-up attempt then failure
- No drive available
Common causes
- Pre-charge resistor degraded
- HV bus capacitor leaking charge
- Contactor coil weak
- Excessive load on HV bus during pre-charge
- Pre-charge relay contact resistance high
Diagnostic steps
- Monitor HV bus voltage during pre-charge attempt
- Test pre-charge resistor value
- Check HV bus capacitor leakage
- Measure contactor coil current
- Isolate sections of HV bus to find excessive load
Repair notes
Replace pre-charge resistor or relay. If HV bus capacitor is faulty, inverter replacement may be needed.
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