DTC P0A1F-123: Battery Energy Control Module: Procedure

1. Measure the voltage between the terminals of the auxiliary battery.

   Standard voltage

   11 to 14 V

NG → CHARGE OR REPLACE AUXILIARY BATTERY 

OK: Go to next step 

1. Remove the service plug grip. Refer to REMOVAL .
2. Remove the battery smart unit. Refer to REMOVAL .

   HINT: 

   Do not disconnect the battery smart unit connectors.

3. Disconnect connector n2 from the battery smart unit.
4. Turn the power switch on (IG).
5. Measure the voltage according to the value(s) in the table below.
   Fig 1: Identifying Battery Smart Unit N2 Connector Terminal End View

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard voltage

   Tester Connection	Specified Condition
   IGC1 (n2-1) - GND (n2-5)	8.6 V or higher

OK → See step   4 

NG: Go to next step 

1. Remove the IGCT relay from the engine room R/B.
2. Measure the resistance according to the value(s) in the table below.
   Fig 2: Identifying Battery Smart Unit N2 Connector End View And IGCT Relay

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance (Check for open)

   Tester Connection	Specified Condition
   IGC1 (n2-1) - IGCT relay 5	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → CHECK AND REPAIR POWER SOURCE CIRCUIT