What Does P0B37 Mean?
The hybrid powertrain control module has detected that the high-voltage service disconnect is in the open (removed) position while the vehicle is attempting to operate, or the disconnect interlock indicates an open condition that is inconsistent with expected vehicle operation. This typically means the safety plug is not fully engaged or has been inadvertently removed.
Safety Warning
Vehicle will not start or will immediately shut down with this fault. The HV bus is physically interrupted when the disconnect is open, so the vehicle cannot operate. Ensure the plug is properly seated before attempting to drive.
Common Causes
40%
Service disconnect plug not fully seated or locking mechanism not engaged after recent service
25%
Faulty interlock switch falsely reporting open condition even with plug properly installed
20%
Damaged service disconnect plug with broken engagement tabs preventing proper connection
15%
Open circuit in the interlock monitoring wiring giving a false disconnect reading
Diagnostic Steps
1
Step 1: Physically verify the service disconnect plug is fully installed and the locking mechanism is engaged. Remove and reseat it firmly, listening for a positive click.
2
Step 2: Inspect the plug's engagement tabs and housing for cracks, damage, or broken plastic that could prevent full insertion.
3
Step 3: With the plug installed, check the interlock switch status via scan tool. It should indicate 'closed.' If it still reads 'open,' the switch or wiring is at fault.
4
Step 4: Test the interlock switch with a DVOM for proper continuity changes when the plug is inserted and removed.
5
Step 5: If the switch is functional, trace the wiring from the switch to the control module for open circuits or connector faults.
Estimated Repair Cost
$50 - $500
Parts + labor, varies by vehicle and location
The hybrid powertrain control module has detected that the high-voltage service disconnect is in the open (removed) position while the vehicle is attempting to operate, or the disconnect interlock indicates an open condition that is inconsistent with expected vehicle operation. This typically means ...
The most common cause of P0B37 (High Voltage Service Disconnect Open) is: Service disconnect plug not fully seated or locking mechanism not engaged after recent service
Typical repair costs for P0B37 range from $50 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will not start or will immediately shut down with this fault. The HV bus is physically interrupted when the disconnect is open, so the vehicle cannot operate. Ensure the plug is properly seated before attempting to drive.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0B37 to identify the root cause.
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Quick Info
Category
Powertrain
System
High Voltage Safety System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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