Toyota Tacoma 2015-2018 Service Manual: Check Bus 5 Lines for Short Circuit

Toyota Tacoma 2015-2018 Service Manual / Can Communication / Can Communication System / Check Bus 5 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 15 (CA5H) and 16 (CA5L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Detection Item	Trouble Area
Resistance between terminals 15 (CA5H) and 16 (CA5L) of central gateway ECU (network gateway ECU) is below 54 Ω.	Short in 5 CAN main line Short in 5 CAN branch line Central gateway ECU (network gateway ECU) Forward recognition camera1 Clearance warning ECU assembly2 Millimeter wave radar sensor assembly1 Blind spot monitor sensor LH3 No. 4 CAN junction connector No. 5 CAN junction connector No. 6 CAN junction connector

*1: w/ Toyota Safety Sense P
*2: w/ Intuitive Parking Assist System
*3: w/ Blind Spot Monitor System

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.

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
J22-1 (CANH) - J22-12 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Clearance warning ECU assembly*1
J22-2 (CANH) - J22-13 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)
J22-3 (CANH) - J22-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 5 CAN junction connector
J22-4 (CANH) - J22-15 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Forward recognition camera*2

*1: w/ Intuitive Parking Assist System
*2: w/ Toyota Safety Sense P

*a	Front view of wire harness connector (to No. 6 CAN Junction Connector)
*b	to Clearance Warning ECU Assembly (w/ Intuitive Parking Assist System)
*c	to Central Gateway ECU (Network Gateway ECU)
*d	to No. 5 CAN Junction Connector
*e	to Forward Recognition Camera (w/ Toyota Safety Sense P)

Result

Result	Proceed to
OK	A
NG (Central gateway ECU (network gateway ECU) CAN main line)	B
NG (No. 5 CAN junction connector CAN main line)	C
NG (ECU or sensor CAN branch lines)	D

REPLACE NO. 6 CAN JUNCTION CONNECTOR

GO TO STEP 3

GO TO STEP 6

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
J22-2 (CANH) - J22-13 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

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 (NO. 5 CAN JUNCTION CONNECTOR)

(a) Reconnect the J22 No. 6 CAN junction connector.

(b) Disconnect the No. 5 CAN junction connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
J21-1 (CANH) - J21-3 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Millimeter wave radar sensor assembly*1
J21-2 (CANH) - J21-4 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 6 CAN junction connector
J21-6 (CANH) - J21-7 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 4 CAN junction connector

*1: w/ Toyota Safety Sense P

*a	Front view of wire harness connector (to No. 5 CAN Junction Connector)
*b	to Millimeter Wave Radar Sensor Assembly (w/ Toyota Safety Sense P)
*c	to No. 6 CAN Junction Connector
*d	to No. 4 CAN Junction Connector

Result

Result	Proceed to
OK	A
NG (No. 4 CAN junction connector CAN main line)	B
NG (to No. 6 CAN junction connector CAN main line)	C
NG (ECU or sensor CAN branch lines)	D

REPLACE NO. 5 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)

GO TO STEP 6

4.	CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR)

(a) Reconnect the J21 No. 5 CAN junction connector.

(b) Disconnect the No. 4 CAN junction connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
J20-1 (CANH) - J20-3 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)
J20-2 (CANH) - J20-4 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 5 CAN Junction Connector
J20-6 (CANH) - J20-7 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Blind spot monitor sensor LH*1

*1: w/ Blind Spot Monitor System

*a	Front view of wire harness connector (to No. 4 CAN Junction Connector)
*b	to Central Gateway ECU (Network Gateway ECU)
*c	to No. 5 CAN Junction Connector
*d	to Blind Spot Monitor Sensor LH (w/ Blind Spot Monitor System)

Result

Result	Proceed to
OK	A
NG (Central gateway ECU (network gateway ECU) CAN main line)	B
NG (to No. 5 CAN junction connector CAN main line)	C
NG (ECU or sensor CAN branch lines)	D

REPLACE NO. 4 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION TERMINAL)

GO TO STEP 6

5.	CHECK FOR SHORT IN CAN BUS LINES (NO. 4 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
J20-1 (CANH) - J20-13 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

Front view of wire harness connector

(to No. 4 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. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

6.	CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR)

(a) Reconnect the CAN junction connector.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N36-15 (CA5H) - N36-16 (CA5L)	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.

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR

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