Cause
Damaged interlock wiring
Physical damage to the interlock loop's wiring rather than corrosion at a joint — a chafed conductor, a cut made during unrelated work, a lead pinched by a cover being refitted, or rodent damage. The distinction from a corroded pin is where you look, not what happens: both open the loop and both shut the vehicle down completely, but this one is found by tracing the harness and the other by opening connectors.
The timing usually names it. An interlock fault appearing immediately after work in the boot, under the rear seat, or anywhere the high voltage cabling runs is far more likely to be a trapped or pinched lead than a coincidental failure. A cover refitted with the loop lead across its sealing face is the classic, and it leaves a visible witness mark.
Intermittent is the harder version and the more revealing one. A conductor broken inside intact insulation, or one chafed to a few strands, opens with vibration or temperature and closes again — so the vehicle shuts down, is recovered, and then works perfectly. Flex the harness section by section with the loop monitored, after isolating the high voltage system by the manufacturer's procedure. As with any interlock fault, do not bypass the loop to keep the vehicle moving.
Typically specialist work. Needs equipment or training most home workshops do not have.
Some of these codes mean you should stop driving
5 of the 5 codes this can cause indicate a fault where continuing to drive risks damage or is unsafe. Which one you have matters more than the cause does — read the code's own page before deciding.
Codes this can cause (5)
Codes where this is a likely explanation first, rather than merely a possible one.
- P0A0C High Voltage System Interlock Circuit A Low Likely for this code Stop driving Critical
- P0A0D High Voltage System Interlock Circuit A High Likely for this code Stop driving Critical
- P0A0E High Voltage System Interlock Circuit A Intermittent Likely for this code Stop driving Critical
- P0A0A High Voltage System Interlock Circuit A Stop driving Critical
- P0A0B High Voltage System Interlock Circuit A Performance Stop driving Critical
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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