ECU Power Source Circuit: Procedure

1. Disconnect the driving support ECU assembly connector.
   Fig 1: Checking L151 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the power switch on (IG).
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   L151-30 (B) - Body ground	Power switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Driving Support ECU Assembly)

NG → See step   3 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 2: Checking L151 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   L151-25 (GND) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Driving Support ECU Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - BODY GROUND) 

OK → See step   7 

1. Remove the instrument panel junction block assembly.
   Fig 3: Identifying Instrument Panel Junction Block Assembly & Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   2E-1 - 2B-16	Always	10 kΩ or higher
   2E-1 - 2B-16	Auxiliary battery voltage applied between terminals 2B-25 and 2B-6	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a

   Instrument Panel Junction Block Assembly

   -

   -

NG → REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

OK: Go to next step 

1. Disconnect the instrument panel junction block assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   L151-30 (B) - 2B-16	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   L151-30 (B) or 2B-16 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVING SUPPORT ECU - INSTRUMENT PANEL JUNCTION BLOCK) 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 4: Identifying 2B Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   2B-4 - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Instrument Panel Junction Block Assembly

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND) 

OK: Go to next step 

1. Disconnect the power management control ECU connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   L136-2 (IG1D) - 2B-25	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   L136-2 (IG1D) or 2B-25 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) 

OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK - AUXILIARY BATTERY)