Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Communication between ECUs connected by LIN Bus off (B278588)

Toyota Corolla Cross (2022-2024) Service Manual / Power Source & Network / Networking / Lin Communication System / Communication between ECUs connected by LIN Bus off (B278588)

DESCRIPTION

If the certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 seconds or more, DTC B278588 will be stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B278588

Communication between ECUs connected by LIN Bus off
  • Errors in LIN communication between ECUs or an open or short in communication lines.
  • The certification ECU (smart key ECU assembly) detects a communication error with an ECU connected to the certification bus lines for 7 seconds or more.
  • Wire harness or connector
  • ID code box (immobiliser code ECU)
  • Certification ECU (smart key ECU assembly)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When using the GTS with the ignition switch off, connect the GTS to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the GTS and the vehicle begins. Then select Model Code "KEY REGIST" under manual mode and enter the following menus: Body Electrical / Smart Key. While using the GTS, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the GTS and the vehicle.
  • Before replacing the certification ECU (smart key ECU assembly) or ID code box (immobiliser code ECU), refer to Registration.
    • for HEV Model: Click here
    • for Gasoline Model: Click here

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - EACH ECU)

(a) Disconnect the I222 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the I20 ID code box (immobiliser code ECU) connector.

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

NOTICE:

Make sure that each ECU is in sleep mode before performing the inspection. To enter sleep mode, turn the ignition switch from ON to off and wait for 180 seconds or more without operating any switches.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

I222-8 (LIN) - I20-2 (LIN1)

Ignition switch off

Below 1 Ω

I222-8 (LIN) - Body ground

Always

10 kΩ or higher

I20-2 (LIN1) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

2.

CLEAR DTC

(a) Connect the I222 certification ECU (smart key ECU assembly) connector.

(b) Connect the I20 ID code box (immobiliser code ECU) connector.

(c) Clear the DTCs.

Body Electrical > Smart Key > Clear DTCs
NEXT

3.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Smart Key > Trouble Codes

Result

Proceed to

B278588 is not output

A

B278588 is output

B
A

REPLACE ID CODE BOX (IMMOBILISER CODE ECU)

B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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