P0A0B High Voltage System Interlock Circuit Low

P0A0B points to a low condition in the high-voltage system interlock circuit. The interlock loop voltage or feedback is lower than the expected state.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System: Hybrid / EV
Scope: iso-sae-controlled-p0
Standard: SAE J2012 / ISO 15031-6
Source: legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not force the vehicle into ready mode or bypass the interlock when the high-voltage safety loop reads low.

Useful checks before replacing parts

Check interlock circuit voltage, service disconnect position, high-voltage connector locks, battery cover switches, freeze-frame data, and hybrid ready status.
Inspect for short-to-ground faults, unseated connectors, bent interlock pins, moisture intrusion, damaged harness wiring, and recently serviced high-voltage parts.
Verify loop continuity and feedback according to service information after disabling and proving the high-voltage system safe.

Related OBD-II codes

These nearby hybrid / ev entries can help compare wording and fault area. They may share the same verification status as the source database.