Toyota CH-R Service Manual: Main Body ECU Communication Stop Mode

Toyota CH-R Service Manual / Networking / Can Communication System / Main Body ECU Communication Stop Mode

DESCRIPTION

Detection Item

Symptom

Trouble Area

Main Body ECU Communication Stop Mode

Any of the following conditions are met:

  • Communication stop for "Main Body" is indicated on the "Communication Bus Check" screen of the Techstream.

    Click here

  • Communication stop history for "Main Body" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "Main Body" is 6 or more.)

    Click here

  • Communication system DTCs (DTCs that start with U) that correspond to "Main Body ECU Communication Stop Mode" in "DTC Combination Table" are output.

    Click here

  • Main body ECU (multiplex network body ECU) branch line or connector
  • Power source circuit of main body ECU (multiplex network body ECU) or instrument panel junction block assembly
  • Main body ECU (multiplex network body ECU) or instrument panel junction block assembly ground circuit
  • Main body ECU (multiplex network body ECU) or instrument panel junction block assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

    Click here

  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the ignition switch to ON, turn the blind spot monitor system on using the blind spot monitor main switch (ON/OFF switch), turn the LDA main switch on and wait for approximately 20 seconds or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.*1

    Click here

  • *1: w/ Smart Key System

HINT:

  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.

CHECK FOR OPEN IN CAN BUS LINES (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) BRANCH LINE)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F15-14 (CANH) - F15-13 (CANL)

Cable disconnected from negative (-) battery terminal

54 to 69 Ω

*a

Front view of wire harness connector

(to Main Body ECU (Multiplex Network Body ECU))
NG

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))
OK

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Remove the main body ECU (multiplex network body ECU).

Click here

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

MB-11 (GND1) - Body ground

Cable disconnected from negative (-) battery terminal

Below 1 Ω

NOTICE:

Perform this inspection with the wire harness connected to the instrument panel junction block assembly.

*a

Front view of wire harness connector

(to Main Body ECU (Multiplex Network Body ECU))

(c) Reconnect the cable to the negative (-) battery terminal.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

MB-31 (BECU) - Body ground

Always

11 to 14 V

MB-30 (ACC) - Body ground

Ignition switch ACC

11 to 14 V

MB-32 (IG) - Body ground

Ignition switch ON

11 to 14 V

NOTICE:

Perform this inspection with the wire harness connected to the instrument panel junction block assembly.

Result

Proceed to

OK

A

NG (BECU)

B

NG (ACC)

C

NG (IG)

D

NG (GND1)

E
A

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

C

GO TO LIGHTING (INT) SYSTEM (ACC SIGNAL CIRCUIT)

D

GO TO LIGHTING (INT) SYSTEM (IG SIGNAL CIRCUIT)

E

GO TO STEP 4

B

3.

CHECK HARNESS AND CONNECTOR (BECU SIGNAL CIRCUIT)

(a) Disconnect the cable from the negative (-) battery terminal.

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

(c) Reconnect the cable to the negative (-) battery terminal.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

3F-1 - Body ground

Always

11 to 14 V

*a

Front view of wire harness connector

(to Instrument Panel Junction Block Assembly)
OK

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BECU SIGNAL CIRCUIT)

4.

CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the 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

3D-3 - Body ground

Cable disconnected from negative (-) battery terminal

Below 1 Ω

*a

Front view of wire harness connector

(to Instrument Panel Junction Block Assembly)
OK

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT)
    Combination Meter ECU Communication Stop Mode
    DESCRIPTION Detection Item Symptom Trouble Area Combination Meter ECU Communication Stop Mode Any of the following conditions are met: ...

    Certification ECU Communication Stop Mode
    DESCRIPTION Detection Item Symptom Trouble Area Certification ECU Communication Stop Mode Any of the following conditions are met: ...

    Other materials:

    Toyota CH-R Service Manual > Blind Spot Monitor System: Short to +B in Outer Mirror Indicator(Slave) (C1AB1)
    DESCRIPTION This DTC is stored when the blind spot monitor sensor RH (Slave) detects a short to +B in the outer rear view mirror indicator RH. DTC No. Detection Item DTC Detection Condition Trouble Area C1AB1 Short to +B in ...

    Toyota CH-R Service Manual > Airbag System: Short in Front Pretensioner Squib LH Circuit (B1905/74-B1908/74)
    DESCRIPTION The front pretensioner squib LH circuit consists of the airbag sensor assembly and front seat outer belt assembly LH. The airbag sensor assembly uses this circuit to deploy the pretensioner when deployment conditions are met. These DTCs are stored when a malfunction is detected in ...

    Toyota C-HR (AX20) 2023-2025 Owner's Manual

    Toyota CH-R Owners Manual

    Toyota CH-R Service Manual

    © 2017-2025 Copyright www.tochr.net
    0.0102