Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM100000001H5W6
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 04/2020]
Title: LIGHTING (EXT): LIGHTING SYSTEM (for HV Model): Back-up Light Circuit; 2020 MY Corolla Corolla HV [01/2019 - 04/2020]

Back-up Light Circuit

DESCRIPTION

The hybrid vehicle control ECU controls the back-up lights via the BKUP LP relay.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Before replacing the hybrid vehicle control ECU, refer to Registration.

    Click here 2020 MY Corolla Corolla HV [01/2019 - 04/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, HV Model): REGISTRATION

PROCEDURE

1.

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

(e) Check for DTCs.

Powertrain > Hybrid Control > Trouble Codes

Result

Proceed to

Hybrid control system DTCs are not output

A

Hybrid control system DTCs are output

B

B

GO TO HYBRID CONTROL SYSTEM

A

2.

CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND)

(a) Disconnect the 4F instrument panel junction block assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4F-3 - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the A57 hybrid vehicle control ECU connector.

(b) Disconnect the 4B instrument panel junction block assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A57-20 (BL) - 4B-19

Always

Below 1 Ω

A57-20 (BL) or 4B-19 - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

CHECK HYBRID VEHICLE CONTROL ECU (OUTPUT VOLTAGE)

*a

Component with harness connected

(Instrument Panel Junction Block Assembly)

(a) Connect the A57 hybrid vehicle control ECU connector.

(b) Connect the 4F and 4B instrument panel junction block assembly connectors.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

4B-19 - Body ground

Power switch off, reverse (R) not selected

Below 1 V

4B-19 - Body ground

Power switch on (IG), reverse (R) selected

11 to 14 V

NG

REPLACE HYBRID VEHICLE CONTROL ECU

OK

5.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (OUTPUT VOLTAGE)

*a

Component with harness connected

(Instrument Panel Junction Block Assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

4A-10 - Body ground

Power switch off, reverse (R) not selected

Below 1 V

4A-10 - Body ground

Power switch on (IG), reverse (R) selected

11 to 14 V

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR

NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL 2020 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2022]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL