Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0A11 (KA/Kc) (2019 2020 2021 2022 2023 2024)
DTC P0A11: DC-DC Converter Activation Circuit Malfunction
General Description
The auto idle stop system equipped vehicle uses the DC-DC converter to prevent electronic accessory reset due to the 12 volt battery voltage lowering when recovering (starter motor running) from auto idle stop condition. The DC-DC converter is connected with DC_STS line which the powertrain control module (PCM) sends a voltage boost request and the local interconnect network (LIN) line which the DC-DC converter sends a diagnostic result to the PCM. When the PCM requests DC-DC converter to boost up the voltage via the DC_STS line, the boost voltage circuit in the DC-DC converter boosts the 12 volt battery voltage and provides to other electrical units. Also, the DC-DC converter sends a DC_STS signal receipt notification to the PCM via the LIN line. If the PCM does not receive a DC_STS signal receipt notification from the DC-DC converter via the LIN for a set time after the PCM sent a voltage boost request via the DC_STS line, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Recovered from auto idle stop condition |
| Sequence | None |
| Duration | 1.0 second or more |
| DTC Type | Two drive cycles, MIL off |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [ Battery ] | 10.5 V | - |
| Vehicle | ON mode | |
| Other | DC_STS ON or within 1.0 second after DC_STS OFF | |
| [ ] : HDS Parameter | ||
Malfunction Threshold
The PCM does not receive a DC_STS signal receipt notification from the DC-DC converter via the LIN for at least 1.0 second.
Possible Cause
The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- DC-DC converter DC_STS line open
- DC-DC converter DC_STS line short to power
- DC-DC converter failure
- PCM internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, a Confirmed DTC, the freeze data, and the on-board snapshot are stored. The MIL does not come on.
Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, the freeze data, and the on-board snapshot can be cleared with the scan tool Clear command.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.