Power Source Circuit [10/2018 - ]: Procedure

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the A36 No. 1 headlight ECU sub-assembly LH connector.
2. Disconnect the A7 No. 1 headlight ECU sub-assembly RH connector.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH
   
   

   Tester Connection	Condition	Specified Condition
   A36-13 (ECUB) - Body ground	Engine switch on (IG) or light control switch in tail or head position	11 to 14 V

   NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH
   
   

   Tester Connection	Condition	Specified Condition
   A7-13 (ECUB) - Body ground	Engine switch on (IG) or light control switch in tail or head position	11 to 14 V

   Result

   Result	Proceed to
   OK	A
   NG (No. 1 Headlight ECU Sub-assembly LH)	B
   NG (No. 1 Headlight ECU Sub-assembly RH)	C

Result: 

B 

See step  4

Result: 

C 

See step  9

Result: 

A 

See step  2

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH
   
   

   Tester Connection	Condition	Specified Condition
   A36-4 (IG) - Body ground	Engine switch on (IG)	11 to 14 V

   NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH
   
   

   Tester Connection	Condition	Specified Condition
   A7-4 (IG) - Body ground	Engine switch on (IG)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

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

   Standard Resistance

   NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH
   
   

   Tester Connection	Condition	Specified Condition
   A36-12 (GND) - Body ground	Always	Below 1 Ω

   NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH
   
   

   Tester Connection	Condition	Specified Condition
   A7-12 (GND) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [10/2018 - 09/2020]  , or refer to  PROBLEM SYMPTOMS TABLE [09/2020 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Inspect the H-LP LH relay.

   Refer to ON-VEHICLE INSPECTION [10/2018 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE H-LP LH RELAY 

Result: 

OK 

See step  5

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   1 (H-LP LH relay) - Body ground	Always	11 to 14 V
   5 (H-LP LH relay) - Body ground	Always	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 (H-LP LH relay) - A36-13 (ECUB)	Always	Below 1 Ω
   3 (H-LP LH relay) or A36-13 (ECUB) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  7

1. Disconnect the 4C instrument panel junction block assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   2 (H-LP LH relay) - 4C-29	Always	Below 1 Ω
   2 (H-LP LH relay) or 4C-29 - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  8

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

   Refer to REMOVAL [09/2014 - ]

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4C-29 - MB-15 (HRLY)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2014 - ] 

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

1. Inspect the H-LP RH relay.

   Refer to ON-VEHICLE INSPECTION [10/2018 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE H-LP RH RELAY 

Result: 

OK 

See step  10

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   1 (H-LP RH relay) - Body ground	Always	11 to 14 V
   5 (H-LP RH relay) - Body ground	Always	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  11

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 (H-LP RH relay) - A7-13 (ECUB)	Always	Below 1 Ω
   3 (H-LP RH relay) or A7-13 (ECUB) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  12

1. Disconnect the O2 main body ECU (multiplex network body ECU) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   2 (H-LP RH relay) - O2-1 (DIM)	Always	Below 1 Ω
   2 (H-LP RH relay) or O2-1 (DIM) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2014 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR