Back-up Light Circuit [06/2020 - 12/2021]: Procedure

1. Check for DTCs.

   Powertrain > Hybrid Control > Trouble Codes 

   OK

   Hybrid control system DTCs are not output.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

GO TO HYBRID CONTROL SYSTEM 

Refer to DIAGNOSTIC TROUBLE CODE CHART [06/2020 - 10/2022]

Result: 

OK 

See step  2

1. Changes the shift lever R position.
2. Using the GTS, read the Data List.

   Body Electrical > Power Distribution Box > Data List 

   Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
   Back-up Light Input Signal	Back-up light input condition	OFF or ON	OFF: Shift lever in any position other than R ON: Shift lever in R	-

   Body Electrical > Power Distribution Box > Data List 

   Tester Display
   Back-up Light Input Signal

   OK

   Display changes according to shift lever operation.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  5

Result: 

OK 

See step  3

1. Changes the shift lever R position.
2. Using the GTS, read the Data List.

   Body Electrical > Power Distribution Box > Data List 

   Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
   Back-up Light Output Signal	Back-up light output condition	OFF or ON	OFF: Back-up light not illuminated ON: Back-up light illuminated	-

   Body Electrical > Power Distribution Box > Data List 

   Tester Display
   Back-up Light Output Signal

   OK

   Display changes according to shift lever operation.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE POWER DISTRIBUTION BOX ASSEMBLY 

Refer to REMOVAL [06/2020 - 12/2021]

Result: 

OK 

See step  4

1. Disconnect the 4F power distribution box assembly connector.
2. Disconnect the R6 rear light socket and wire RH connector.
3. Disconnect the R7 rear light socket and wire LH connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4F-38 - R6-1 (B)	Always	Below 1 Ω
   4F-38 or R6-1 (B) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE POWER DISTRIBUTION BOX ASSEMBLY 

Refer to REMOVAL [06/2020 - 12/2021]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the power distribution box assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   4B-29 - Body ground	Ignition switch ON, shift lever not in R	Below 1 V
   	Ignition switch ON, shift lever in R	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE POWER DISTRIBUTION BOX ASSEMBLY 

Refer to REMOVAL [06/2020 - 12/2021]

Result: 

NG 

See step  6

1. Disconnect the 4B power distribution box assembly connector.
2. Disconnect the A121 hybrid vehicle control ECU connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4B-29 - A121-49 (BL)	Always	Below 1 Ω
   4B-29 or A121-49 (BL) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE HYBRID VEHICLE CONTROL ECU 

Refer to REMOVAL [06/2020 - 12/2021]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR