Generic fault code
P0A0A — High voltage system interlock, circuit A: malfunction
The control unit stores code P0A0A when it detects this fault: “High voltage system interlock, circuit A: malfunction”.
Indicative severity: CriticalHybrid and electric (high voltage)
Reviewed by Daniel Morales, founder of Reprorace SL, on
What does code P0A0A mean?
The high-voltage system of hybrid and electric cars: the traction battery, the inverter, the electric motors and their cooling. It works at hundreds of volts: only a technician trained in high voltage may check it, never the driver.
- System
- P · Powertrain
- Area
- Hybrid and electric (high voltage) · Car system: Electrical system and battery
- Type
- Generic (SAE J2012 / ISO 15031-6): the same meaning on every make
- Indicative severity
- Critical. Stop the vehicle safely and do not use it until repaired (restraints, high voltage).
What usually causes code P0A0A?
- Loose or corroded connector, backed-out terminals
- Damaged, chafed or pinched wiring
The most likely causes come first. Only a check on the car confirms which one is yours.
What are the symptoms of code P0A0A?
- Hybrid, EV or high-voltage system warning on the dashboard
- Reduced power, or the car does not switch to READY
- In hybrids, the gasoline engine runs more than usual
These are the usual symptoms of this kind of fault: not all of them always appear, and sometimes you notice nothing.
Can I keep driving with code P0A0A?
No. Stop the vehicle somewhere safe and do not use it until a professional has checked it: the fault affects the restraint systems (airbags and pretensioners) or the high-voltage system. Call roadside assistance.
This is guidance only: only someone who checks the car can say whether it is safe to drive.
An indicative description of the code's generic meaning. Each manufacturer may give it a different meaning, conditions or tests: always follow its service information and your workshop's advice.
What you can do yourself
For this kind of fault
Never open, disconnect or touch high-voltage parts (orange cables, traction battery, inverter): they can hold dangerous voltages even with the car switched off. Stop the car in a safe place, call for assistance and have it checked by a workshop with technicians trained in high voltage.
Read the code and keep the report: with an ECO-LITE in the OBD socket you see it on your phone or computer, with the data captured when the fault happened.
Do not touch anything in this system: no airbag connectors or connectors under the seats, no orange cables or high-voltage parts. Only a professional with the right training and equipment should check them.
Do not clear the code to switch off the warning light: the fault is still there and the workshop needs the stored data.
Do not use the car until it has been checked: call roadside assistance or book the workshop, and take the report with you.
Read your car's fault codes on your phone
With an ECO-LITE in the OBD socket you see the codes in your account, with the data captured when the fault happened, and your workshop can check them remotely, always with your permission.
Related codes
- P0A0DHigh voltage system interlock, circuit A: signal high
- P0A2BDrive motor A temperature sensor A, circuit: range/performance
- P0A3FDrive motor A position sensor, circuit: malfunction
- P0A78Drive motor A inverter: performance
- P0A7EHybrid/EV battery pack A: over temperature
- P0A7FHybrid/EV battery pack A: deterioration
P0Axx codes: hybrid propulsion
In the glossary
Read more: Remote OBD diagnostics: what it is, how it works and what it can't do