Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: Check Bus 3 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 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Detection Item

Trouble Area

No resistance exists between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

  • Short to GND in CAN main lines
  • Short to GND in CAN branch lines
  • Central gateway ECU (network gateway ECU)
  • Navigation receiver assembly*1
  • Radio and display receiver assembly*2
  • NO. 6 CAN junction connector
  • *1: for Navigation Receiver Type
  • *2: for Radio and Display Type

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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 GND 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.

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

Text in Illustration

*1

DLC3

-

-

*a

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)

*c

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) - D4-4 (CG)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Central gateway ECU (network gateway ECU)

J22-20 (CANL) - D4-4 (CG)

J22-10 (CANH) - D4-4 (CG)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Central gateway ECU (network gateway ECU)

J22-21 (CANL) - D4-4 (CG)

J22-11 (CANH) - D4-4 (CG)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Navigation receiver assembly*1 or Radio and display receiver assembly*2

J22-22 (CANL) - D4-4 (CG)

  • *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

A

REPLACE NO. 6 CAN JUNCTION CONNECTOR

C

GO TO STEP 3

B

2.

CHECK FOR SHORT TO GND 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

*1

DLC3

-

-

*a

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection

Condition

Specified Condition

J22-9 (CANH) - D4-4 (CG)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

J22-20 (CANL) - D4-4 (CG)

J22-10 (CANH) - D4-4 (CG)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

J22-21 (CANL) - D4-4 (CG)

OK

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

NG

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 GND 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 GND is connected.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

N36-6 (CA3H) - D4-4 (CG)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

N36-21 (CA3H) - D4-4 (CG)

Cable disconnected from negative (-) battery terminal

200 Ω or higher

Text in Illustration

*a

Component with harness connected

(Central Gateway ECU (Network Gateway ECU))

*b

Front view of DLC3

HINT:

If the resistance changes to 200 Ω or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.

OK

REPLACE ECU OR SENSOR

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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