High Voltage Service Disconnect Open
The P0B37 code indicates that the high voltage service disconnect switch in a hybrid or electric vehicle is in the open position, meaning the high voltage battery is disconnected from the rest of the vehicle. This switch is typically used for safety during maintenance, but if it is open while driving, the vehicle will lose high voltage power and may enter a reduced power mode or stop. The issue could be due to a faulty switch, wiring problems, or a control module fault.
01. Most Common Causes
- Faulty high voltage service disconnect switch
- Damaged wiring or connectors in the high voltage circuit
- Malfunctioning battery management system (BMS) or hybrid control module
02. Symptoms You Will Notice
- Vehicle may not start or move
- Reduced power or limp mode
- Warning lights on dashboard (e.g., check hybrid system)
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes.
Step 2: Visually inspect the high voltage service disconnect switch and its wiring for damage or corrosion.
Step 3: Test the switch continuity with a multimeter; replace if open when it should be closed.
Step 4: Check the battery management system for faults and perform a system reset if necessary.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. The high voltage battery is disconnected, so the vehicle may lose power unexpectedly or fail to operate. Have it towed to a repair shop.
How much does it cost to fix?▼
Typically between $50 and $150 for diagnosis and switch replacement, but costs can vary if wiring or module repairs are needed.