Toyota Tacoma (2015-2018) Service Manual: Check Bus 3 Lines for Short Circuit

Toyota Tacoma (2015-2018) Service Manual / Can Communication / Can Communication System / 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 gateway ECU) is below 54 Ω.

Detection Item	Trouble Area
Resistance between terminals 6 (CA3H) and 21 (CA3L) of central gateway ECU (network gateway ECU) is below 54 Ω.	Short in CAN main lines Short 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 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.

Text in Illustration

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) - J22-20 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)
J22-10 (CANH) - J22-21 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)
J22-11 (CANH) - J22-22 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Navigation receiver assembly1 or Radio and display receiver assembly2

*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 IN CAN BUS LINES (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.

Standard Resistance:

Tester Connection	Condition	Specified Condition
J22-9 (CANH) - J22-20 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher
J22-10 (CANH) - J22-21 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

Text in Illustration

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

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

3.	CHECK FOR SHORT 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 short circuited CAN branch line is connected.

Standard Resistance:

Tester Connection	Condition	Specified Condition
N36-6 (CA3H) - N36-21 (CA3L)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

Text in Illustration

*a	Component with harness connected (Central Gateway ECU (Network Gateway ECU))

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.

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR

Check Bus 3 Line for Short to +B

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DESCRIPTION There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and termin ...

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