NETWORKING: CAN COMMUNICATION SYSTEM: Check Bus 1 Line for Short to +B; 2018 MY Camry [03/2017

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and +B when there is no resistance between terminal 23 (CA1H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 8 (CA1L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

Symptom

Trouble Area

There is no resistance between terminal 23 (CA1H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 8 (CA1L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

Short to +B in CAN main bus line
Short to +B in CAN branch line
Central gateway ECU (network gateway ECU)
Forward recognition camera
(w/ Toyota Safety Sense P)
Millimeter wave radar sensor assembly
(w/ Toyota Safety Sense P)
Blind spot monitor sensor RH
(w/ Blind Spot Monitor System)
Rear television camera assembly
(w/ Parking Assist Monitor System)
No. 1 CAN junction connector
No. 5 CAN junction connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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 and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes 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

Tester Connection

Condition

Specified Condition

Connected to

A66-1 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

Millimeter wave radar sensor assembly*

A66-7 (CANL) - K68-16 (BAT)

A66-2 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

Forward recognition camera*

A66-8 (CANL) - K68-16 (BAT)

A66-3 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

Central gateway ECU (network gateway ECU)

A66-9 (CANL) - K68-16 (BAT)

A66-5 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

No. 5 CAN junction connector

A66-11 (CANL) - K68-16 (BAT)

Result

Proceed to

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

NG (Line to No. 5 CAN junction connector)

NG (Line to ECU or sensor)

Tester Connection

Condition

Specified Condition

A66-3 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

A66-9 (CANL) - K68-16 (BAT)

Tester Connection

Condition

Specified Condition

Connected to

R98-1 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

Central gateway ECU (network gateway ECU)

R98-11 (CANL) - K68-16 (BAT)

R98-3 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

Blind spot monitor sensor RH*1

R98-13 (CANL) - K68-16 (BAT)

R98-4 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

Rear television camera assembly*2

R98-14 (CANL) - K68-16 (BAT)

R98-5 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

No. 1 CAN junction connector

R98-15 (CANL) - K68-16 (BAT)

Result

Proceed to

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

NG (Line to No. 1 CAN junction connector)

NG (Line to ECU or sensor)

Tester Connection

Condition

Specified Condition

R98-1 (CANH) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

R98-11 (CANL) - K68-16 (BAT)

(b) Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to +B is connected.

Tester Connection

Condition

Specified Condition

K76-23 (CA1H) - K68-16 (BAT)

Cable disconnected from negative (-) battery terminal

6 kΩ or higher

K76-8 (CA1L) - K68-16 (BAT)

HINT:

If the resistance changes to 6 kΩ or higher 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 to +B in the wire harness and repair or replace the wire harness or connector if necessary.