P0A8B
DTC P0A8B
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 42v DC and 14v DC Buses via the APM, bi-directional 42v DC to 14v DC converter. During all of the APM functions the voltage is closely monitored between the internal voltage and the 12-volt underhood battery for voltage correlation faults.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0A8B 14-Volt Power Module System Voltage
CONDITIONS FOR RUNNING THE DTC
- Engine is running for 30 seconds.
- The SGCM has received voltage on the ignition 0 voltage circuit.
- The SGCM has turned ON and no configuration DTC is present.
- This diagnostic shall run every 100 milliseconds.
CONDITIONS FOR SETTING THE DTC
APM voltage is not equal to 12-volt battery voltage ±2 volts.
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.
TEST
