Toyota Tacoma (2015-2018) Service Manual: Check Bus 3 Line for Short to +B

Toyota Tacoma (2015-2018) Service Manual / Can Communication / Can Communication System / Check Bus 3 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 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

Detection Item	Trouble Area
No resistance exists between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.	Short to +B in CAN main lines Short to +B in CAN branch lines Central gateway ECU (network gateway ECU) Navigation receiver assembly1 Radio and display receiver assembly2 No. 6 CAN junction connector

*1: for Navigation Receiver Type
*2: for Radio and Display Type

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

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.
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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.
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Some parts must be initialized and set when replacing or removing and installing parts.
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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.
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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 SHORT TO +B IN CAN BUS LINE (NO. 6 CAN JUNCTION CONNECTOR)

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

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

Text in Illustration

DLC3

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

to Navigation Receiver Assembly (for Navigation Receiver Type) or Radio and Display Receiver Assembly (for Radio and Display Type)

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
J22-9 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J22-20 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J22-10 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J22-21 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J22-11 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Navigation receiver assembly1 or Radio and display receiver assembly2
J22-22 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

*1: for Navigation Receiver Type
*2: for Radio and Display Type

Result

Result	Proceed to
OK	A
NG (Central gateway ECU (network gateway ECU) CAN main line)	B
NG (ECU or sensor CAN branch lines)	C

REPLACE NO. 6 CAN JUNCTION CONNECTOR

GO TO STEP 3

2.	CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 6 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the N36 central gateway ECU (network gateway ECU) connector.

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

Text in Illustration

DLC3

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
J22-9 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
J22-20 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
J22-10 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
J22-21 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

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

3.	CHECK FOR SHORT TO B+ IN CAN BUS LINES (ECU, SENSOR)

(a) Reconnect the CAN junction connector.

(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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N36-6 (CA3H) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N36-21 (CA3L) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

Text in Illustration

Component with harness connected

(Central Gateway ECU (Network Gateway ECU))

Front view of DLC3

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.

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR

Open in One Side of Bus 2 Branch Line

DESCRIPTION When the CAN bus main lines are normal (no open, short to ground, short to +B or short between lines) and there is an ECU or sensor on the "Communication Bus Check" screen t ...

Check Bus 3 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 6 (CA3H) and 21 (CA3L) of the central gateway ECU (network ga ...

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