DTC Advanced Diagnostics: P0A94 (3.5L Engine) (2022 2023 2024)
DTC P0A94: DC-DC Converter Performance Problem
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 for the powertrain control module (PCM) to send a voltage boost request and the local interconnect network (LIN) line for sending a diagnostic result to the PCM. When the self-diagnostic circuit in the DC-DC converter detects a failure, it is noticed to the PCM via the LIN line. If the PCM receives a DC-DC converter failure information for a set time, the PCM detects a DC-DC converter performance problem and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 5.0 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 | |
[ ]: HDS Parameter
Malfunction Threshold
The PCM receives a DC-DC converter failure information via the LIN line for at least 5.0 seconds.
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 +B_DC/DC1 line open
- DC-DC converter +B_DC/DC1 line short
- DC-DC converter +B_DC/DC2 line open
- DC-DC converter +B_DC/DC2 line short
- DC-DC converter DC_STS line short
- DC-DC converter IG1_VSA/ABS line open
- DC-DC converter VST_OUT1 line short
- DC-DC converter VST_OUT2 line short
- DC-DC converter GND line open
- Electrical unit failure
- 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.