Diagnostic Item 8: Diagnose the lines between CAN_L and CAN_H for short circuit <RH drive vehicles except Hong Kong and Singapore>


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


Short circuit may be present between the CAN_L and H lines when the resistance between the CAN bus lines (CAN_L and H lines) is less than 2 Ω.

COMMENTS ON TROUBLE SYMPTOM


The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or a ECU may be defective.

TROUBLESHOOTING HINTS



DIAGNOSTIC PROCEDURE

STEP 1. Connector check: C-125 intermediate connector

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

Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

STEP 2. Resistance measurement at the 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 connector, and measure at its male-side intermediate connector (at the front 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)Resistance between C-125 intermediate connector terminal Nos.26 and 27
OK: 120 ± 20 Ω

Q. Is the check result normal?

<Within 120 ± 20 Ω> Go to Step 3.

<Not within 120 ± 20 Ω> Go to Step 20.

STEP 3. Connector check: C-09 joint connector (CAN2)

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 and its short pins are not damaged.

Q. Is the check result normal?

Go to Step 4.

Repair a defective connector or replace the joint connector.

STEP 4. Resistance measurement at C-09 joint connector (CAN2).
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 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)Resistance between C-09 joint connector (CAN2) terminal Nos.6 and 17
OK: 120 ± 20 Ω

(5)Resistance between C-09 joint connector (CAN2) terminal Nos.8 and 19
OK: 1 kΩ or more

(6)Resistance between C-09 joint connector (CAN2) terminal Nos.5 and 16
OK: 1 kΩ or more

(7)Resistance between C-09 joint connector (CAN2) terminal Nos.4 and 15
OK: 1 kΩ or more

(8)Resistance between C-09 joint connector (CAN2) terminal Nos.7 and 18
OK: 1 kΩ or more

Q. Are the check result normal?

YES <all of the measurement results are within the normal value> : Go to Step 19.

NO <The resistance between terminal Nos.6 and 17 is less than 120 ± 20 Ω> : Go to Step 5.

NO <The resistance between terminal Nos.8 and 19 is less than 1 kΩ> : Go to Step 8.

NO <The resistance between terminal Nos.5 and 16 is less than 1 kΩ> : Go to Step 11.

NO <The resistance between terminal Nos.4 and 15 is less than 1 kΩ> : Go to Step 14.

NO <The resistance between terminal Nos.7 and 18 is less than 1 kΩ> : Go to Step 17.

STEP 5. Connector check: C-02 combination meter connector

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

Q. Is the check result normal?

Go to Step 6.

Repair the defective connector.

STEP 6. Resistance measurement at C-09 joint connector (CAN2).
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 combination meter 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-09 joint connector (CAN2) terminal Nos.6 and 17
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<More than 2 Ω> Go to Step 7.

<2 Ω or less> Repair the wiring harness between joint connector (CAN2) and the combination meter connector.

STEP 7. Resistance measurement at C-02 combination meter connector.
caution A digital multimeter should be used. For details refer to .

(1)Remove the combination meter, and measure at the equipment side.

(2)Resistance between C-02 combination meter connector terminal Nos.23 and 24
OK: 120 ± 20 Ω

Q. Is the check result normal?

<Within 120 ± 20 Ω> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<Not within 120 ± 20 Ω> Replace the combination meter.

STEP 8. Connector check: C-106 A/C-ECU connector

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

Q. Is the check result normal?

Go to Step 9.

Repair the defective connector.

STEP 9. Resistance measurement at C-09 joint connector (CAN2).
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 A/C-ECU 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-09 joint connector (CAN2) terminal Nos.8 and 19
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<More than 2 Ω> Go to Step 10.

<2 Ω or less> Repair the wiring harness between joint connector (CAN2) and the A/C-ECU connector.

STEP 10. Resistance measurement at C-106 A/C-ECU connector.
caution A digital multimeter should be used. For details refer to .

(1)Remove the A/C-ECU, and measure at the equipment side.

(2)Resistance between C-106 A/C-ECU connector terminal Nos.8 and 9.
OK: 1 kΩ or more

Q. Is the check result normal?

<1 kΩ or more> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<Less than 1 kΩ> Replace the A/C-ECU.

STEP 11. Connector check: C-221 ETACS-ECU connector

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

Q. Is the check result normal?

Go to Step 12.

Repair the defective connector.

STEP 12. Resistance measurement at C-09 joint connector (CAN2).
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 ETACS-ECU 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-09 joint connector (CAN2) terminal Nos.5 and 16
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<More than 2 Ω> Go to Step 13.

<2 Ω or less> Repair the wiring harness between joint connector (CAN2) and the ETACS-ECU connector.

STEP 13. Resistance measurement at C-221 ETACS-ECU connector.
caution A digital multimeter should be used. For details refer to .

(1)Remove the ETACS-ECU, and measure at the equipment side.

(2)Resistance between C-221 ETACS-ECU connector terminal Nos.72 and 73
OK: 1 kΩ or more

Q. Is the check result normal?

<1 kΩ or more> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<Less than 1 kΩ> Replace the ETACS-ECU.

STEP 14. Connector check: C-119 SRS-ECU connector

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

Q. Is the check result normal?

Go to Step 15.

Repair the defective connector.

STEP 15. Resistance measurement at C-09 joint connector (CAN2).
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 SRS-ECU 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-09 joint connector (CAN2) terminal Nos.4 and 15
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<More than 2 Ω> Go to Step 16.

<2 Ω or less> Repair the wiring harness between joint connector (CAN2) and the SRS-ECU connector.

STEP 16. Resistance measurement at C-119 SRS-ECU connector.
caution A digital multimeter should be used. For details refer to .

(1)Remove the SRS-ECU, and measure at the equipment side.

(2)Resistance between C-119 SRS-ECU connector terminal Nos.32 and 43
OK: 1 kΩ or more

Q. Is the check result normal?

<1 kΩ or more> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<Less than 1 kΩ> Replace the SRS-ECU.

STEP 17. Connector check: C-126 diagnosis connector

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

Q. Is the check result normal?

Go to Step 18.

Repair the defective connector.

STEP 18. Resistance measurement at C-09 joint connector (CAN2).
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 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-09 joint connector (CAN2) terminal Nos.7 and 18
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<2 more than Ω> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<2 Ω or less> Repair the wiring harness between joint connector (CAN2) and the diagnosis connector.

STEP 19. Resistance measurement at C-09 joint connector (CAN2).
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-09 joint connector (CAN2) terminal Nos.11 and 22
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<2 more than Ω> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<2 Ω or less> Repair the wiring harness between joint connector (CAN2) and the intermediate connector.

STEP 20. 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 21.

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

STEP 21. Resistance measurement at the 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 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)Resistance between A-07 joint connector (CAN1) terminal Nos.3 and 6.
OK: 120 ± 20 Ω

(5)Resistance between A-07 joint connector (CAN1) terminal Nos.2 and 5.
OK: 1 kΩ or more

Q. Are the check result normal?

YES <all of the measurement results are within the normal value> : Go to Step 31.

NO <The resistance between terminal Nos.3 and 6 is less than 120 ± 20 Ω> : Go to Step 22.

NO <The resistance between terminal Nos.2 and 5 is less than 1 kΩ> : Go to Step 28.

STEP 22. Connector check: A-16 intermediate connector

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

Q. Is the check result normal?

Go to Step 23.

Repair the defective connector.

STEP 23. Resistance measurement at the A-16 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 connector, and measure at its male-side intermediate connector (at the control 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)Resistance between A-16 intermediate connector terminal Nos.6 and 12
OK: 120 ± 20 Ω

Q. Is the check result normal?

<Within 120 ± 20 Ω> Go to Step 27.

<Not within 120 ± 20 Ω> Go to Step 24.

STEP 24. Connector check: C-112 engine-A/T-ECU connector

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

Q. Is the check result normal?

Go to Step 25.

Repair the defective connector.

STEP 25. Resistance measurement at the A-16 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 engine-A/T-ECU connector 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)Resistance between A-16 intermediate connector terminal Nos.6 and 12
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<More than 2 Ω> Go to Step 26.

<2 Ω or less> Repair the wiring harness between the intermediate connector and the engine-A/T-ECU connector.

STEP 26. Resistance measurement at C-112 engine-A/T-ECU connector.
caution A digital multimeter should be used. For details refer to .

(1)Remove the engine-A/T-ECU, and measure at the equipment side.

(2)Resistance at C-112 engine-A/T-ECU connector terminal Nos.61 and 62
OK: 120 ± 20 Ω

Q. Is the check result normal?

<Within 120 ± 20 Ω> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<Not within 120 ± 20 Ω> Replace the engine-A/T-ECU.

STEP 27. Resistance measurement at the 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 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)Resistance between A-07 joint connector (CAN1) terminal Nos.3 and 6.
OK: 120 ± 20 Ω

Q. Is the check result normal?

<All the measurement results are within the normal value> Follow diagnostic item 15 "Diagnose CAN bus lines thoroughly." Refer to .

<The resistance between terminal Nos.3 and 6 measures less than 120 ± 20 Ω> Repair the wiring harness between the joint connector (CAN1) and the intermediate connector.

STEP 28. Connector check: A-03 ABS-ECU connector

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

Q. Is the check result normal?

Go to Step 29.

Repair the defective connector.

STEP 29. Resistance measurement at the 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 ABS-ECU 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 Nos.2 and 5.
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<More than 2 Ω> Go to Step 30.

<2 Ω or less> Repair the wiring harness between joint connector (CAN1) and the ABS-ECU connector.

STEP 30. Resistance measurement at A-03 ABS-ECU connector.
caution A digital multimeter should be used. For details refer to .


(1)Connect special tool MB991974 to the ABS-ECU connector, and measure by using the check connector (connect the ECU side only).

(2)Resistance between special tool MB991974 check connector terminal Nos.11 and 15.
OK: 1 kΩ or more

Q. Is the check result normal?

<1 kΩ or more> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<Less than 1 kΩ> Replace the ABS-ECU.

STEP 31. Resistance measurement at the 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)Measure the continuity between A-07 joint connector (CAN1) terminal Nos.1 and 4.
OK: More than 2 Ω
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<2 more than Ω> Follow diagnostic item 15, Diagnose CAN bus lines thoroughly. Refer to .

<2 Ω or less> Repair the wiring harness between joint connector (CAN1) and the intermediate connector.