Inspection Procedure

HINT:

Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

1. CHECK HARNESS AND CONNECTOR (ECM - BATTERY AND BODY GROUND) 
   Fig 1: Identifying A38 & C53 ECU Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Disconnect the A38 and C53 ECU connectors.
   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART
      
      

      Tester Connection	Condition	Specified Condition
      C53-81 (E1) - Body ground	Always	Below 1 Ω
      C53-42 (E02) - Body ground
      C53-43 (E01) - Body ground
      C53-82 (ME01) - Body ground

   3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage 

   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   Tester Connection	Condition	Specified Condition
   A38-1 (BATT) - Body ground	Always	11 to 14 V
   A38-2 (+B2) - Body ground	When battery positive (+) voltage is applied to terminal A38-34 (MREL)
   A38-3 (+B) - Body ground

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: REPLACE ECM  (See ECM )