DTC P1AB2, P1A64, P1A65, P1A66, P1A67, P1A68, P1A69, P1A6A, or P1A6B for GMC Truck GMC Sierra Denali 2005
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. |
