P0AA8 OBD-II: Hybrid Battery Voltage Isolation Sensor Circuit Range/Performance

OBD II Fault Code

• OBD II P0AA8

OBD-II Code High voltage system may not operate is defined as a Hybrid Battery Voltage Isolation Sensor Circuit Range/Performance

The high voltage system uses a battery voltage isolation sensor inside the battery control module to monitor separation of the high and low voltage systems. If sensor fails, P0AA8 will set. The high voltage system may become disabled.

High voltage system may not operate Symptoms

• High voltage system may not operate
• Vehicle will not charge

Common Problems That Trigger the P0AA8 Code

• Battery Smart Unit failure