Diagnostic Item 17: Diagnose the lines between the joint connectors (CAN1 and CAN2) <LH drive vehicles>


caution When servicing a CAN bus line, earth yourself by touching a metal object such as an unpainted water pipe. If you fail to do, a component connected to the CAN bus line may be broken.


TROUBLE JUDGMENT


If the M.U.T.-III cannot receive any signal from the ABS-ECU and the engine-ECU <M/T> or engine-A/T-ECU <A/T>, CAN bus line connector(s) are broken or an open circuit has occurred.

COMMENTS ON TROUBLE SYMPTOM


The CAN bus line wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector.

POSSIBLE CAUSE



DIAGNOSTIC PROCEDURE

STEP 1. Connector check: C-09 joint connector (CAN2) and C-125 intermediate connector


caution The strand end of the twist wire should be within 10 cm from the connector. For details refer to .

When checking the joint connector, ensure that its wiring harness side is not damaged.

Q. Are the check results normal?

Go to Step 2.

Repair a defective connector or replace the joint connector.

STEP 2. Resistance measurement at C-09 joint connector (CAN2) and C-125 intermediate connector.
caution A digital multimeter should be used. For details refer to .
caution The test wiring harness should be used. For details refer to .


(1)Disconnect the joint connector (CAN2) and the intermediate connector, and measure at the wiring harness side.
(2)Ignition switch: OFF (LOCK)
(3)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(4)Continuity between C-125 intermediate connector terminal No.26 and C-09 joint connector (CAN2) terminal No.4
OK: 2 Ω or less

(5)Continuity between C-125 intermediate connector terminal No.27 and C-09 joint connector (CAN2) terminal No.15
OK: 2 Ω or less
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Are the check results normal?

<All the voltages measure 2 Ω or less> Go to Step 3 .

<Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN2) and the intermediate connector.

STEP 3. Connector check: A-07 joint connector (CAN1)
note When checking A-07 joint connector (CAN1), disassemble and check the engine compartment relay box by referring to .

caution The strand end of the twist wire should be within 10 cm from the connector. For details refer to .
When checking the joint connector, ensure that its wiring harness side is not damaged.

Q. Is the check result normal?

Go to Step 4.

Repair a defective connector or replace the joint connector (front wiring harness assembly).

STEP 4. Resistance measurement at C-125 intermediate connector and A-07 joint connector (CAN1).
note When checking A-07 joint connector (CAN1), disassemble and check the engine compartment relay box by referring to .
caution A digital multimeter should be used. For details refer to .
caution The test wiring harness should be used. For details refer to .


(1)Disconnect the joint connector (CAN1) and the intermediate connector, and measure at the wiring harness side.
(2)Ignition switch: OFF (LOCK)
(3)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(4)Continuity between A-07 joint connector (CAN1) terminal No.1 and C-125 intermediate connector terminal No.27
OK: 2 Ω or less

(5)Continuity between A-07 joint connector (CAN1) terminal No.4 and C-125 intermediate connector terminal No.26
OK: 2 Ω or less
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Are the check results normal?

<All the resistances measure 2 Ω or less> Follow diagnostic item 19 "Diagnose the lines from the main bus line to the engine-ECU <M/T> or engine-A/T-ECU <A/T>" (Refer to ) or diagnostic item 20 "Diagnose the lines between CAN main bus line and the ABS-ECU (Refer to ).

<Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN1) and the intermediate connector.