Diagnostic Instructions
DTC Descriptor
DTC P0AFA: Hybrid Battery System Voltage Low
Circuit/System Description
The starter generator control module (SGCM) monitors the hybrid battery voltage to verify that the output voltage (36 volts) Is within normal operating value (above 22 volts). If the output voltage is not within this value, this DTC will
set.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
36 volt output voltage is less than 22 volts for 2 seconds.
Action Taken When the DTC Sets
• | Stop PWM (MGU shutdown) |
Conditions for Clearing the DTC
36 volt output voltage increases to greater than 22 volts.
Diagnostic Aids
• | Possible battery cable open |
• | Possible fuse/relay block electrical failure |
Reference Information
Schematic Reference
Hybrid Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Starter/Generator Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool Hybrid System Voltage parameter in the SGCM data list. The voltage should be greater than 22 volts. If the parameter displays less than the specified value, refer to SGCM 36 volt Output Terminal Circuit
Low.
- Ignition ON, observe the scan tool Hybrid System Voltage parameter in the BECM data list. The voltage should be greater than 22 volts. If the parameter displays less than the specified value, refer to Hybrid Battery Pack Voltage Low.
Circuit/System Testing
SGCM 36 volt Output Terminal Circuit Low
- If DTC is history, refer to
Testing for Intermittent Conditions and Poor Connections.
- Ignition ON, test for greater than 22 volts at the SGCM battery positive 36 volt output voltage stud.
⇒ | If less than the specified value, test the 36 volt cable for an open/high resistance or short to ground. |
⇒ | If greater than the specified value, replace the SGCM. |
Hybrid Battery Pack Voltage Low
- If DTC is history, refer to
Testing for Intermittent Conditions and Poor Connections.
- Gain access to the hybrid battery pack. Refer to
Hybrid Battery Service Disconnect/Connect.
- Ignition OFF, test battery pack voltage for greater than 22 volts.
⇒ | If less than the specified value, replace the battery pack. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.