BMS High-Voltage Bus Pre-Charge Timeout

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

1. Monitor HV bus voltage during pre-charge attempt
2. Test pre-charge resistor value
3. Check HV bus capacitor leakage
4. Measure contactor coil current
5. 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.

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