Cause
High voltage service plug not fully seated
The removable link a technician pulls to disconnect the traction battery before working on it — deliberately designed to break the interlock and power-off circuits obviously when it is anything less than fully home, because ambiguously connected is the one state a safety disconnect must never occupy.
A hybrid that will not power on after service work near the battery has this at the top of its list. The plug seats in two stages on most designs — pushed home, then a lever or latch rotated to lock — and stopping at stage one leaves the vehicle immobilised with interlock or power-off codes stored. Reseating it is the entire repair. It costs nothing to check and is embarrassing to discover after an afternoon of diagnosis, which is exactly why it goes first.
Typically specialist work. Needs equipment or training most home workshops do not have.
Some of these codes mean you should stop driving
7 of the 12 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 (12)
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
- P0A0D High Voltage System Interlock Circuit A High Likely for this code Stop driving Critical
- P0A27 Hybrid/EV Battery Power Off Circuit Likely for this code High
- P0A28 Hybrid/EV Battery Power Off Circuit Low Likely for this code High
- P0B33 High Voltage Service Disconnect Circuit Likely for this code Stop driving High
- P0B34 High Voltage Service Disconnect Circuit Performance Likely for this code Stop driving High
- P0B37 High Voltage Service Disconnect Open Likely for this code Stop driving High
- P0A0B High Voltage System Interlock Circuit A Performance Stop driving Critical
- P0A0E High Voltage System Interlock Circuit A Intermittent Stop driving Critical
- P0AA2 Hybrid/EV Battery Positive Contactor Circuit Stuck Open High
- P0AA5 Hybrid/EV Battery Negative Contactor Circuit Stuck Open High
- P0AE3 Hybrid/EV Battery Precharge Contactor Circuit Stuck Open High
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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- The car — make, model, year and engine. The same fault behaves differently on each.
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