Cause
Corroded interlock connector pin
Corrosion on a pin in the high voltage interlock loop — the thin low voltage circuit threaded through every high voltage connector and cover so the vehicle can tell whether the system is still sealed. Its whole design intent is to be broken easily, because it must detect a cover that has been removed, and that same sensitivity is what makes a corroded pin enough to trigger it.
The response is deliberately severe and worth expecting. A loop the module cannot verify is treated as an exposed high voltage system, so contactors open and the vehicle refuses to run — no limp mode, no warning phase. A car that has stopped dead with an interlock code is behaving correctly, and it is a much better outcome than the alternative.
It is genuinely a safety circuit, so treat it as one. Do not bridge, bypass or back-probe a loop to prove a fault; the point of the circuit is that it fails safe, and defeating it defeats the protection. Follow the manufacturer's shutdown and isolation procedure before opening any connector in this loop. The commonest honest finding is moisture in a connector under the vehicle or in the boot, and cleaning and resealing the joint is the repair — but only after the system has been properly isolated.
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.
- P0A0A High Voltage System Interlock Circuit A Likely for this code Stop driving Critical
- P0A0B High Voltage System Interlock Circuit A Performance Likely for this code Stop driving Critical
- P0A0C High Voltage System Interlock Circuit A Low Likely for this code Stop driving Critical
- P0A0E High Voltage System Interlock Circuit A Intermittent Likely for this code Stop driving Critical
- P0A0D High Voltage System Interlock Circuit A High 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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