Diagnosis Item 2: Diagnose shorts in the earth to CAN bus line



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.




FUNCTION




TROUBLE JUDGEMENT CONDITIONS




TROUBLESHOOTING HINTS



  • Malfunction of the wiring harness
  • Malfunction of the connector
  • Malfunction of each ECU

DIAGNOSIS PROCEDURE


STEP 1. Check the CAN bus lines. Resistance measurement at C-22 diagnosis connector.


caution A digital multimeter should be used. For details refer to .
caution The test wiring harness should be used. For details refer to .
note This inspection allows you to check that there is a short to earth in either CAN_H line or CAN_L line. Thus, in the following steps, check the CAN bus line that is defective.






(1)Disconnect engine-ECU connector C-103 and ETACS-ECU connector C-219, and measure the resistance at harness side of diagnosis connector C-22.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-22 diagnosis connector terminal No.6 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-22 diagnosis connector terminal No.14 (CAN_L) and body earth
OK: 1 kΩ or more

Q. Is the check result normal?

<Both of the measurement results show 1 kΩ or more> Go to Step 23.

<Either of CAN_H line or CAN_L line the measurement results show less than 1 kΩ > Go to Step 2.

STEP 2. Check the CAN line. Resistance measurement at C-53 <LHD> or C-35 <RHD> 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 intermediate connector C-53 <LHD> or C-35 <RHD>, and measure at its male-side intermediate connector (at the control wiring harness side).
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-53 <LHD> or C-35 <RHD> intermediate connector terminal No.6 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-53 <LHD> or C-35 <RHD> intermediate connector terminal No.7 (CAN_L) and body earth
OK: 1 kΩ or more

Q. Is the check result normal?

<1 kΩ or more> Go to Step 7.

<Less than 1 kΩ > Go to Step 3.

STEP 3. Check the CAN line between joint connector (CAN2) and the engine-ECU. Resistance measurement at C-01 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 joint connector (CAN2), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-01 joint connector (CAN2) terminal No.9 (CAN_H) and body earth <LHD>
OK: 1 kΩ or more

(4)Resistance between C-01 joint connector (CAN2) terminal No.10 (CAN_H) and body earth <RHD>
OK: 1 kΩ or more

(5)Resistance between C-01 joint connector (CAN2) terminal No.20 (CAN_L) and body earth <LHD>
OK: 1 kΩ or more

(6)Resistance between C-01 joint connector (CAN2) terminal No.21 (CAN_L) and body earth <RHD>
OK: 1 kΩ or more

Q. Is the check result normal?

YES <M/T> : <1 kΩ or more> Repair intermediate connector C-53 <LHD> or C-35 <RHD>, or the wiring harness between joint connector (CAN2) and intermediate connector C-53 <LHD> or C-35 <RHD>.

YES <A/T> : <1 kΩ or more> Go to Step 4.

NO : <Less than 1 kΩ > Repair the wiring harness between joint connector (CAN2) and the engine-ECU connector.

STEP 4. Check the CAN line between joint connector (CAN2) and the A/T-ECU. Resistance measurement at C-01 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 joint connector (CAN2), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-01 joint connector (CAN2) terminal No.10 (CAN_H) and body earth <LHD>
OK: 1 kΩ or more

(4)Resistance between C-01 joint connector (CAN2) terminal No.9 (CAN_H) and body earth <RHD>
OK: 1 kΩ or more

(5)Resistance between C-01 joint connector (CAN2) terminal No.21 (CAN_L) and body earth <LHD>
OK: 1 kΩ or more

(6)Resistance between C-01 joint connector (CAN2) terminal No.20 (CAN_L) and body earth <RHD>
OK: 1 kΩ or more

Q. Is the check result normal?

<1 kΩ or more> Repair intermediate connector C-53 <LHD> or C-35 <RHD>, or the wiring harness between joint connector (CAN2) and intermediate connector C-53 <LHD> or C-35 <RHD>.

<Less than 1 kΩ > Go to Step 5.

STEP 5. M.U.T.-III CAN bus diagnostics [A/T-ECU connector disconnected]




(1)Disconnect A/T-ECU connector C-20, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Repair the wiring harness between joint connector (CAN2) and the A/T-ECU connector.

Check the A/T-ECU connector, and repair if necessary. If the A/T-ECU connector is in good condition, go to Step 6.

STEP 6. M.U.T.-III CAN bus diagnostics (retest the system)


Diagnose CAN bus lines, and check if M.U.T.-III screen shows normal state.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Check the A/T-ECU connector, and repair if necessary. If the A/T-ECU connector is in good condition, replace the A/T-ECU.

STEP 7. Check CAN line between joint connector (CAN1) and the ETACS-ECU. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.9 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.20 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<1 kΩ or more> Go to Step 8.

<Less than 1 kΩ > Repair the wiring harness between joint connector (CAN1) and the ETACS-ECU connector.

STEP 8. Check the CAN line between joint connector (CAN1) and the RV meter. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.7 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.18 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

YES <vehicles without ABS, ASTC and A/C> : <1 kΩ or more> Go to Step 22.

YES <vehicles with ABS> : <1 kΩ or more> Go to Step 10.

YES <vehicles with ABS> : <1 kΩ or more> Go to Step 13.

YES <vehicles without ABS and ASTC, and with A/C> : <1 kΩ or more> Go to Step 20.

NO : <Less than 1 kΩ > Go to Step 9.

STEP 9. M.U.T.-III CAN bus diagnostics [RV meter connector disconnected]




(1)Disconnect RV meter connector C-171, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Repair the wiring harness between joint connector (CAN1) and the RV meter connector.

Check the RV meter connector, and repair if necessary. If the RV meter connector is in good condition, repair the RV meter power supply circuit. (Refer to GROUP 54A - RV meter .)

STEP 10. Check the CAN line between joint connector (CAN1) and the ABS-ECU. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.5 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.16 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

YES <vehicles without A/C> : <1 kΩ or more> Go to Step 22.

YES <vehicles with A/C> : <1 kΩ or more> Go to Step 20.

NO : <Less than 1 kΩ > Go to Step 11.

STEP 11. M.U.T.-III CAN bus diagnostics [ABS-ECU connector disconnected]



(1)Disconnect ABS-ECU connector A-01, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Check intermediate connector (C-13), and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN1) and the ABS-ECU connector.

Check the ABS-ECU connector, and repair if necessary. If the ABS-ECU connector is in good condition, go to Step 12.

STEP 12. M.U.T.-III CAN bus diagnostics (retest the system)


Diagnose CAN bus lines, and check if M.U.T.-III screen shows normal state.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Check the ABS-ECU connector, and repair if necessary. If the ABS-ECU connector is in good condition, replace the hydraulic unit assembly.

STEP 13. Check the CAN line between joint connector (CAN1) and the ASTC-ECU. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.5 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.16 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<1 kΩ or more> Go to Step 16.

<Less than 1 kΩ > Go to Step 14.

STEP 14. M.U.T.-III CAN bus diagnostics [ASTC-ECU connector disconnected]



(1)Disconnect ASTC-ECU connector A-48, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Check intermediate connector C-13, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN1) and the ASTC-ECU connector.

Check the ASTC-ECU connector, and repair if necessary. If the ASTC-ECU connector is in good condition, go to Step 15.

STEP 15. M.U.T.-III CAN bus diagnostics (retest the system)


Diagnose CAN bus lines, and check if M.U.T.-III screen shows normal state.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Check the ASTC-ECU connector, and repair if necessary. If the ASTC-ECU connector is in good condition, replace the hydraulic unit assembly.

STEP 16. Check the CAN line between joint connector (CAN1) and the steering wheel sensor. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.3 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.14 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<1 kΩ or more> Go to Step 18.

<Less than 1 kΩ > Go to Step 17.

STEP 17. M.U.T.-III CAN bus diagnostics [steering wheel sensor connector disconnected]




(1)Disconnect steering wheel sensor connector C-308, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Repair the wiring harness between joint connector (CAN1) and the steering wheel sensor connector.

Check the steering wheel sensor connector, and repair if necessary. If the steering wheel sensor connector is in good condition, repair the steering wheel sensor power supply circuit.

STEP 18. Check the CAN line between joint connector (CAN1) and the G and yaw rate sensor. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.4 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.15 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

YES <vehicles without A/C> : <1 kΩ or more> Go to Step 22.

YES <vehicles with A/C> : <1 kΩ or more> Go to Step 20.

NO : <Less than 1 kΩ > Go to Step 19.

STEP 19. M.U.T.-III CAN bus diagnostics [G and yaw rate sensor connector disconnected]




(1)Disconnect G and yaw rate sensor connector C-144, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Repair the wiring harness between joint connector (CAN1) and the G and yaw rate sensor connector.

Check the G and yaw rate sensor connector, and repair if necessary. If the G and yaw rate sensor connector is in good condition, repair the G and yaw rate sensor power supply circuit.

STEP 20. Check the CAN line between joint connector (CAN1) and the A/C-ECU. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.6 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.17 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<1 kΩ or more> Go to Step 22.

NO : <Less than 1 kΩ > Go to Step 21.

STEP 21. M.U.T.-III CAN bus diagnostics [A/C-ECU connector disconnected]




(1)Disconnect A/C-ECU connector C-43, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Repair the wiring harness between joint connector (CAN1) and the A/C-ECU connector.

Check the A/C-ECU connector, and repair if necessary. If the A/C-ECU connector is in good condition, repair the A/C-ECU power supply circuit. (Refer to GROUP 55B .)

STEP 22. Check the CAN line between joint connector (CAN1) and the diagnosis connector. Resistance measurement at C-119 joint connector (CAN1).


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 joint connector (CAN1), and measure at the wiring harness side.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.

(3)Resistance between C-119 joint connector (CAN1) terminal No.10 (CAN_H) and body earth
OK: 1 kΩ or more

(4)Resistance between C-119 joint connector (CAN1) terminal No.21 (CAN_L) and body earth
OK: 1 kΩ or more
(5)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?

<1 kΩ or more> Repair the intermediate connector C-53 <LHD> or C-35 <RHD>, or the wiring harness between joint connector (CAN1) and the intermediate connector C-53 <LHD> or C-35 <RHD>.

<Less than 1 kΩ > Repair the diagnosis connector, or the wiring harness between joint connector (CAN1) and the diagnosis connector.

STEP 23. M.U.T.-III CAN bus diagnostics [engine-ECU connector disconnected]




(1)Disconnect engine-ECU connector C-103 and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

Go to Step 25.

Check the engine-ECU connector, and repair if necessary. If the engine-ECU connector is in good condition, go to Step 24.

STEP 24. M.U.T.-III CAN bus diagnostics (retest the system)


Diagnose CAN bus lines, and check if M.U.T.-III screen shows normal state.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Check the engine-ECU connector, and repair if necessary. If the engine-ECU connector is in good condition, replace the engine-ECU.

STEP 25. M.U.T.-III CAN bus diagnostics [ETACS-ECU connector disconnected]




(1)Disconnect ETACS-ECU connector C-219, and diagnose by using the M.U.T.-III.

(2)Diagnose CAN bus lines, and check if M.U.T.-III screen is as shown in the illustration.

Q. Does M.U.T.-III screen correspond to the illustration?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).

Check the ETACS-ECU connector, and repair if necessary. If the ETACS-ECU connector is in good condition, go to Step 26.

STEP 26. M.U.T.-III CAN bus diagnostics (retest the system)


Diagnose CAN bus lines, and check if M.U.T.-III screen shows normal state.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Check the ETACS-ECU connector, and repair if necessary. If the ETACS-ECU connector is in good condition, replace the ETACS-ECU.