Toyota CH-R Service Manual: Check Bus 1 Lines for Short Circuit

Toyota CH-R Service Manual / Networking / Can Communication System / Check Bus 1 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 23 (CA1H) and 8 (CA1L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom

Trouble Area

Resistance between terminals 23 (CA1H) and 8 (CA1L) of the central gateway ECU (network gateway ECU) is below 54 Ω.
  • Short in CAN main bus lines
  • Short in CAN branch lines
  • Central gateway ECU (network gateway ECU)
  • Millimeter wave radar sensor assembly

    (w/ Toyota Safety Sense P)

  • Forward recognition camera

    (w/ Toyota Safety Sense P)

  • Blind spot monitor sensor LH

    (w/ Blind Spot Monitor System)

  • No. 1 CAN junction connector
  • No. 6 CAN junction connector

    (w/ Blind Spot Monitor System)

WIRING DIAGRAM

w/o Blind Spot Monitor System

w/ Blind Spot Monitor System

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 blind spot monitor system on using the blind spot monitor main switch (ON/OFF switch), turn the cruise control main switch on, turn the LDA main switch on and then drive the vehicle at a speed of 40 km/h (25 mph) or more for approximately 52 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

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 VEHICLE TYPE

(a) Check vehicle type.

Result

Proceed to

w/o Blind Spot Monitor System

A

w/ Blind Spot Monitor System

B
B

GO TO STEP 4

A

2.

CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR)

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

(b) Disconnect the No. 1 CAN junction connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

F112-2 (CANH) - F112-13 (CANL)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Forward recognition camera*1

F112-3 (CANH) - F112-14 (CANL)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Millimeter wave radar sensor assembly*1

F112-4 (CANH) - F112-15 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

Central gateway ECU (network gateway ECU)

F112-5 (CANH) - F112-16 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

Central gateway ECU (network gateway ECU)
  • *1: w/ Toyota Safety Sense P

*a

Front view of wire harness connector

(to No. 1 CAN Junction Connector)

*b

to Forward Recognition Camera

(w/ Toyota Safety Sense P)

*c

to Millimeter Wave Radar Sensor Assembly

(w/ Toyota Safety Sense P)

*d

to Central Gateway ECU (Network Gateway ECU)

Result

Proceed to

OK

A

NG (Line to central gateway ECU (network gateway ECU))

B

NG (Line to ECU or sensor)

C
A

REPLACE NO. 1 CAN JUNCTION CONNECTOR
C

GO TO STEP 8

B

3.

CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the F74 central gateway ECU (network gateway ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F112-4 (CANH) - F112-15 (CANL)

Cable disconnected from negative (-) battery terminal

1 MΩ or higher

F112-5 (CANH) - F112-16 (CANL)

Cable disconnected from negative (-) battery terminal

1 MΩ or higher

*a

Front view of wire harness connector

(to No. 1 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)
OK

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

NG

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

4.

CHECK FOR SHORT IN CAN BUS LINES (NO. 6 CAN JUNCTION CONNECTOR)

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

(b) Disconnect the No. 6 CAN junction connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

M92-1 (CANH) - M92-12 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

Central gateway ECU (network gateway ECU)

M92-6 (CANH) - M92-17 (CANL)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Blind spot monitor sensor LH

M92-11 (CANH) - M92-22 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 1 CAN junction connector

*a

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)

*c

to Blind Spot Monitor Sensor LH

*d

to No. 1 CAN Junction Connector

Result

Proceed to

OK

A

NG (Line to central gateway ECU (network gateway ECU))

B

NG (Line to No. 1 CAN junction connector)

C

NG (Line to ECU or sensor)

D
A

REPLACE NO. 6 CAN JUNCTION CONNECTOR
C

GO TO STEP 6

D

GO TO STEP 8

B

5.

CHECK FOR SHORT IN CAN BUS LINES (NO. 6 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the F74 central gateway ECU (network gateway ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

M92-1 (CANH) - M92-12 (CANL)

Cable disconnected from negative (-) battery terminal

1 MΩ or higher

*a

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)
OK

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

NG

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

6.

CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR)

(a) Reconnect the M92 No. 6 CAN junction connector.

(b) Disconnect the No. 1 CAN junction connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

F112-2 (CANH) - F112-13 (CANL)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Forward recognition camera*1

F112-3 (CANH) - F112-14 (CANL)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Millimeter wave radar sensor assembly*1

F112-4 (CANH) - F112-15 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 6 CAN junction connector

F112-5 (CANH) - F112-16 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

Central gateway ECU (network gateway ECU)
  • *1: w/ Toyota Safety Sense P

*a

Front view of wire harness connector

(to No. 1 CAN Junction Connector)

*b

to Forward Recognition Camera

(w/ Toyota Safety Sense P)

*c

to Millimeter Wave Radar Sensor Assembly

(w/ Toyota Safety Sense P)

*d

to No. 6 CAN Junction Connector

*e

to Central Gateway ECU (Network Gateway ECU)

Result

Proceed to

OK

A

NG (Line to central gateway ECU (network gateway ECU))

B

NG (Line to No. 6 CAN junction connector)

C

NG (Line to ECU or sensor)

D
A

REPLACE NO. 1 CAN JUNCTION CONNECTOR
C

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)
D

GO TO STEP 8

B

7.

CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the F74 central gateway ECU (network gateway ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F112-5 (CANH) - F112-16 (CANL)

Cable disconnected from negative (-) battery terminal

1 MΩ or higher

*a

Front view of wire harness connector

(to No. 1 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)
OK

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

NG

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

8.

CHECK FOR SHORT IN CAN BUS LINES (ECU OR SENSOR)

(a) Reconnect all wire harness connectors.

(b) Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.

Click here

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F74-23 (CA1H) - F74-8 (CA1L)

Cable disconnected from negative (-) battery terminal

54 to 69 Ω

HINT:

  • If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
  • If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short in the wire harness and repair or replace the wire harness or connector if necessary.

*a

Component with harness connected

(Central Gateway ECU (Network Gateway ECU))
OK

REPLACE ECU OR SENSOR
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
    Restraints Occupant Classification System Module Communication Stop Mode
    DESCRIPTION Detection Item Symptom Trouble Area Restraints Occupant Classification System Module Communication Stop Mode Any of the follow ...

    Check Bus 1 Line for Short to +B
    DESCRIPTION There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminal 23 (CA1H) of the central gateway ECU (network gateway ECU) and terminal ...

    Other materials:

    Toyota CH-R Service Manual > Steering Lock System: Unable to Unlock Steering Wheel (Engine cannot Start)
    DESCRIPTION The steering lock actuator or upper bracket assembly activates the steering lock motor and moves the lock bar into the steering column to lock the steering. The steering may not unlock when the lock bar gets stuck in the lock hole of the steering column. In this case, if the engine ...

    Toyota CH-R Owners Manual > Child restraint systems: Child restraint system fixed with a child restraint LATCH anchor
    ■ Child restraint LATCH anchors LATCH anchors are provided for the rear outboard seats. (Buttons displaying the location of the anchors are attached to the seats.) ■ When installing in the rear outboard seats Install the child restraint system in accordance to the operation manual encl ...

    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