Toyota Tacoma (2015-2018) Service Manual: Check Bus 5 Line for Short to +B

Toyota Tacoma (2015-2018) Service Manual / Can Communication / Can Communication System / Check Bus 5 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 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

Detection Item	Trouble Area
No resistance exists between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 16 (CA5L) 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) 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.
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
Some parts must be initialized and set when replacing or removing and installing parts.
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

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.

*1	DLC3	-	-
*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)	-	-

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
J22-1 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Clearance warning ECU assembly*1
J22-12 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Clearance warning ECU assembly*1
J22-2 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J22-13 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J22-3 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 5 CAN junction connector
J22-14 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 5 CAN junction connector
J22-4 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Forward recognition camera*2
J22-15 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Forward recognition camera*2

*1: w/ Intuitive Parking Assist System
*2: 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 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.

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
J22-2 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
J22-13 (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 LINE (NO. 5 CAN JUNCTION CONNECTOR)

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

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

DLC3

Front view of wire harness connector

(to No. 5 CAN Junction Connector)

to Millimeter Wave Radar Sensor Assembly

(w/ Toyota Safety Sense P)

to No. 6 CAN Junction Connector

to No. 4 CAN Junction Connector

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
J21-1 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Millimeter wave radar sensor assembly*1
J21-3 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Millimeter wave radar sensor assembly*1
J21-2 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 6 CAN junction connector
J21-4 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 6 CAN junction connector
J21-6 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 4 CAN junction connector
J21-7 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 4 CAN junction connector

*1: w/ Toyota Safety Sense P

Result

Result	Proceed to
OK	A
NG (No. 4 CAN junction connector CAN main line)	B
NG (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 BUS LINE OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)

GO TO STEP 6

4.	CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR)

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

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

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

to No. 5 CAN Junction Connector

to Blind Spot Monitor Sensor LH

(w/ Blind Spot Monitor System)

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
J20-1 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J20-3 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Central gateway ECU (network gateway ECU)
J20-2 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 5 CAN junction connector
J20-4 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	No. 5 CAN junction connector
J20-6 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Blind spot monitor sensor LH*1
J20-7 (CANL) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher	Blind spot monitor sensor LH*1

*1: w/ Blind Spot Monitor System

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. 4 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR)

GO TO STEP 6

5.	CHECK FOR SHORT TO +B IN CAN BUS LINE (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.

DLC3

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
J20-1 (CANH) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
J20-3 (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. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

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

(a) Reconnect the CAN junction connector.

Component with harness connected

(Central Gateway ECU (Network Gateway ECU))

Front view of DLC3

(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
N36-15 (CA5H) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
N36-16 (CA5L) - D4-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

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

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 g ...

Check Bus 5 Line for Short to GND

DESCRIPTION There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and termi ...

Other materials:

Operation Check
OPERATION CHECK 1. CHECK NAVIGATION SYSTEM NORMAL CONDITION (a) If the symptom is applicable to any of the following, it is intended behavior, and not a malfunction. Symptom Answer A longer route than expected is chosen. Depending on the road co ...

Removal
REMOVAL CAUTION / NOTICE / HINT CAUTION: Some of these service operations affect the SRS airbag system. Read the precautionary notices concerning the SRS airbag system before servicing. Click here PROCEDURE 1. PRECAUTION NOTICE: After turning the ignition switch off, waiting time may be ...

ECM Communication Circuit Malfunction (C1203)
DESCRIPTION The circuit is used to send TRAC and VSC control information from the skid control ECU (brake actuator assembly) to the ECM, and engine control information from the ECM to the skid control ECU (brake actuator assembly) through the CAN communication system. for 4WD or w/ Rear Diff ...