DTC P0A11 (1.5 L Engine) (2020 2021)
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 12 volt battery voltage lowering when recovering (starter motor running) from idle stop condition. The DC-DC converter is connected with DCDC 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 results to the PCM. When the PCM requests DC-DC converter to boost up the voltage via the DCDC STS line, the voltage boost 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 STS signal receipt notification to the PCM via the LIN line. If the PCM does not receive a 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 DCDC STS line, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Recovered from idle stop condition |
| Sequence | None |
| Duration | 5 seconds 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 | STS ON or within 5 seconds after STS OFF | |
[ ]: HDS Parameter
Malfunction Threshold
The PCM does not receive a STS signal receipt notification from the DC-DC converter via the LIN for at least 5 seconds.
Possible Cause
NOTE: 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 DCDC STS line open
- 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 and the freeze data are stored. The MIL does not come on.
Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.