P0A1B-788

DESCRIPTION

If the MG ECU is reset due to an auxiliary battery voltage drop or abnormality, the HV control ECU will detect this DTC.

DTC No.	INF Code	DTC Detection Condition	Trouble Area
P0A1B	788	Error in reset signal from the power source IC	Auxiliary battery voltage Wire harness or connector w/ converter inverter assembly (MG ECU)

MONITOR DESCRIPTION

When detecting an abnormal reset of the CPU caused by the power supply IC in the MG ECU, the HV control ECU will illuminate the MIL and set a DTC.

WIRING DIAGRAM

INSPECTION PROCEDURE

CAUTION:

1. Before inspecting the high-voltage system, take safety precautions to prevent electrical shocks, such as wearing insulated gloves and removing the service plug grip. After removing the service plug grip, put it in your pocket to prevent other technicians from reconnecting it while you are working on the high-voltage system.
   
2. After disconnecting the service plug grip, wait for at least 5 minutes before touching any of the high-voltage connectors or terminals.
   

HINT:

At least 5 minutes is required to discharge the high-voltage capacitor inside the w/ converter inverter assembly.

1. CHECK CONNECTION CONDITION OF MG ECU CONNECTOR (LOOSENESS AND POOR CONTACT)

CAUTION:

Be sure to wear insulated gloves.

1. Turn the ignition switch off and remove the service plug grip. (Click here)

   NOTICE:

   Do not put the vehicle into the READY-on state with the service plug grip removed as this may cause a malfunction.

2. Remove the inverter cover. (Click here)

   NOTICE:

   1. Wrap the interlock round terminal for the inverter cover with vinyl tape to prevent it from shorting to ground.
      
   2. Prevent water in the reservoir tank from entering the inverter.
      
   3. Removing the inverter cover causes the MG ECU board to be exposed. Therefore, temporarily install the inverter cover for each area to be inspected.
      

3. Check the connections of the MG ECU connectors.

   OK:

   Connectors are connected securely and there is no poor connection.
   

NG	CONNECT SECURELY

OK

2. CHECK HARNESS AND CONNECTOR (IGCT RELAY - MG ECU)

CAUTION:

Be sure to wear insulated gloves.

1. Check that the service plug grip is removed.

2. Remove the IGCT relay from the engine room R/B No.2.

3. Disconnect the I25 connector from the MG ECU.

4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for open):

   Tester Connection	Specified Condition
   +B (I25-7) - Engine room R/B No.2 IGCT relay teminal 5	Below 1 Ω
   +B2 (I25-4) - Engine room R/B No.2 IGCT relay teminal 5	Below 1 Ω

   Standard Resistance (Check for short):

   Tester Connection	Specified Condition
   +B (I25-7) or +B2 (I25-4) - Body ground	10 kΩ or higher

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3. INSPECT MG ECU (+B VOLTAGE)

CAUTION:

Be sure to wear insulated gloves.

1. Check that the service plug grip is removed.

2. Measure the voltage according to the value(s) in the table below when the ignition switch is in the ON position.

   Standard Voltage:

   Tester Connection	Specified Condition
   +B (I25-7) - Body ground	10 V or more
   +B2 (I25-4) - Body ground	10 V or more

   NOTICE:

   Turning the ignition switch to the ON position with the service plug and inverter cover removed causes interlock switch system DTCs to be stored. Clear the DTCs after performing the inspection.

NG	CHECK AND REPLACE BATTERY

OK
REPLACE W/ CONVERTER INVERTER ASSEMBLY