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DTC No. P0A8D-00 Low voltage of auxiliary battery fault
 
 
 
 
DTC SET CONDITION
Check Condition
  • The power supply mode of the electric motor switch is ON (READY indicator: ON).
Judgment Criterion
  • Low voltage status of the backup power supply is detected for 20 seconds or more.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the 12V battery (insufficient charge, run out of battery life, dirty or loose terminals)
  • Malfunction of the DC-DC converter
  • Malfunction of the battery cable
  • Damaged wiring harness and connectors
  • Malfunction of the PHEV-ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
1.M.U.T.-IIISE other system DTC
Check whether the DC-DC converter sets the following DTCs.
  • DTC No. P1AA1-94 DCDC converter failure(Stop of conversion)
  • DTC No. P1AA2-16 DC12V Battery under voltage
Are the DTCs set?
Troubleshoot the set DTCs.
 
2.12V battery check
Check the 12V battery terminal for dirt and looseness, and perform an 12V battery test (Refer to Power Supply, Ground & Circuit Elements - Battery Inspection Work Flow).
Is the check result normal?
Repair or replace the 12V battery (Refer to Power Supply, Ground & Circuit Elements - Battery Removal and Installation), then go to
 
3.Check the installation of the B terminal on On Board Charger (OBC)/DC-DC converter.
Check that the B terminal of the On Board Charger (OBC)/DC-DC converter is installed properly.
Is the check result normal?
Repair the part installed improperly.
 
4.Check of open circuit in B line between On Board Charger (OBC)/DC-DC converter and 12V battery
Is the check result normal?
Replace the battery cable (Refer to Removal and Installation).
 
5.Check of open circuit in BAT line between PHEV-ECU and fuse box.
Is the check result normal?
Repair the faulty part.
 
6.Check whether the DTC is set again.
Is the DTC set?
Replace the PHEV-ECU (Refer to PHEV-ECU REMOVAL AND INSTALLATION).
The trouble can be an intermittent malfunction (Refer to General Information - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).