ECU Power Source Circuit [03/2017 - ]: Procedure

1. Disconnect the 3A and 3C instrument panel junction block assembly connectors.
2. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   3A-27 - Body ground	Always	11 to 14 V
   3C-19 - Body ground	Always	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Instrument Panel Junction Block Assembly)

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  2

1. Disconnect the 3B instrument panel junction block assembly connector.
2. Disconnect the A73 and D6 main body ECU (network gateway ECU) connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3B-18 - Body ground	Always	Below 1 Ω
   A73-4 (GND)- Body ground	Always	Below 1 Ω
   D6-1 (GND - Body ground	Always	Below 1 Ω

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Remove the instrument panel junction block assembly (Refer to REMOVAL [06/2016 - ] ).
2. Remove the main body ECU (network gateway ECU) from the instrument panel junction block assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *a

   Component without harness connected (Instrument Panel Junction Block Assembly

   -

   -

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3A-27 - MB-1 (BECU)	Always	Below 1 Ω
   3C-19 - MB-32 (BMPX)	Always	Below 1 Ω
   3B-18 - MB-11 (GND)	Always	Below 1 Ω

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [03/2017 - ]  

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [06/2016 - ]