Circuit Description
The purpose of the accessory power module (APM), integral to the starter/generator control module (SGCM), is to control the amount and direction of energy flowing between the 42 V DC and 14 V DC buses via the APM, bi-directional 42 V
DC to 14 V DC converter. All APM functions will only be run when in the enable mode. APM current will be defined as the current flowing through the outputs. APM power is bi-directional, with negative current representing 14-42 direction, and positive
current representing the 42-14 direction.
When the APM power conversion direction is set to a value of 42 V to 14 V, the energy will flow from the 42 V DC Bus to the 14 V DC Bus via the APM. When the service charge or jump starting is requested, the energy will flow
from the 14 V DC Bus to the 42 V DC Bus via the APM. When the APM power conversion direction is set to a value of Off, the APM will be turned OFF, and not consume or transfer any power. When the APM power conversion direction is set to a value
of Invalid, the energy will flow from the 42 V DC Bus to the 14 V DC Bus via the APM.
The following DTCs are for internal failures within the SGCM.
| • | P1AB2 is hybrid system voltage. |
| • | P1A64 is for SGCM reset. |
| • | P1A65 is SGCM long term memory performance. |
| • | P1A66 is SGCM loop overrun. |
| • | P1A67 is SGCM options incorrect. |
| • | P1A68 is failed SGCM programming read only memory (ROM). |
| • | P1A69 is failed SGCM programming random access memory (RAM). |
| • | P1A6A is failed SGCM read only memory (ROM). |
| • | P1A6B is failed SGCM 5-volt reference circuit. |
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC P1AB2 Hybrid System Voltage |
| • | DTC P1A64 Starter/Generator Control Module Reset |
| • | DTC P1A65 Starter/Generator Control Module Long Term Memory Performance |
| • | DTC P1A66 Starter/Generator Control Module Loop Overrun |
| • | DTC P1A67 Starter/Generator Control Module Options Incorrect |
| • | DTC P1A68 Starter/Generator Control Module Programming Read Only Memory (ROM) |
| • | DTC P1A69 Starter/Generator Control Module Random Access Memory (RAM) |
| • | DTC P1A6A Starter/Generator Control Module Read Only Memory (ROM) |
| • | DTC P1A6B Starter/Generator Control Module 5-Volt Reference Circuit |
Conditions for Running the DTC
| • | Engine running for 30 seconds |
| • | The SGCM has received voltage on the ignition 0 voltage circuit. |
| • | The SGCM has turned ON and no configuration DTC are present. |
| • | This diagnostic shall be run every 100 ms. |
| • | Reference voltage is stable and accurate. |
Conditions for Setting the DTC
| • | P1AB2 is 42-volt correlation fault within the SGCM. |
| • | P1A64 is for energy storage control module (ESCM) and SGCM is abnormally reset. |
| • | P1A65 is SGCM long term memory performance. |
| • | P1A66 is SGCM loop overrun. |
| • | P1A67 is SGCM options incorrect. |
| • | P1A68 is electrically erasable programmable read-only memory (EEPROM) malfunction was detected. EEPROM is not equal to the checksum stored in EEPROM at power down. |
| • | P1A69 is failed SGCM programming random access memory (RAM). |
| • | P1A6A is failed SGCM read only memory (ROM). |
| • | P1A6B is one or both of the reference range voltages are out of range. |
Action Taken When the DTC Sets
| • | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The driver information center (DIC), if equipped, may display a message. |
Conditions for Clearing the DTC
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
