Diagnosis Item 3: Diagnose shorts in the earth to CAN bus line. <Vehicles for GCC>


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 JUDGEMENT CONDITIONS


The M.U.T.-III judges the trouble when it is impossible to receive the periodically sent data and the voltage of CAN_H or CAN_L line is less than 1.0 V.

TROUBLESHOOTING HINTS



DIAGNOSIS PROCEDURE

STEP 1. Check the CAN bus lines. Resistance measurement at diagnosis connector.
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
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 and ETACS-ECU connector, and measure the resistance at harness side of diagnosis connector.
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between diagnosis connector terminal No. 6 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between 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 24.
<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-213 intermediate connector.
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
(1)Disconnect the C-213 intermediate connector, and measure at its female-side intermediate connector (at the front wiring harness side).
(2)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between C-213 intermediate connector terminal No. 1 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between C-213 intermediate connector terminal No. 2 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
<1 kΩ or more> Go to Step 13.
<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 joint connector (CAN2).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
  • Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN2) terminal No. 11 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN2) terminal No. 22 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
YES : <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 CVT-ECU. Resistance measurement at joint connector (CAN2).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN2) terminal No. 7 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN2) terminal No. 18 (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 5.

STEP 5. M.U.T.-III CAN bus diagnostics [CVT-ECU connector disconnected].
caution Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(1)Disconnect CVT-ECU connector, 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, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN2) and the CVT-ECU connector.

Check the CVT-ECU connector, and repair if necessary. If the CVT-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 CVT-ECU connector, and repair if necessary. If the CVT-ECU connector is in good condition, replace the CVT-ECU.

STEP 7. Check the CAN line between joint connector (CAN2) and the ASC-ECU. Resistance measurement at joint connector (CAN2).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN2) terminal No. 9 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN2) terminal No. 20 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
<1 kΩ or more> Go to Step 10.
<Less than 1 kΩ > Go to Step 8.

STEP 8. M.U.T.-III CAN bus diagnostics [ASC-ECU connector disconnected].
caution Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(1)Disconnect ASC-ECU connector, 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 ASC-ECU connector.

Check the ASC-ECU connector, and repair if necessary. If the ASC-ECU connector is in good condition, go to Step 9.

STEP 9. 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 ASC-ECU, and repair if necessary. If the ASC-ECU connector is in good condition, replace the ASC-ECU. (Refer to GROUP 35C - Hydraulic Unit ).

STEP 10. Check the CAN line between joint connector (CAN2) and the EPS-ECU. Resistance measurement at joint connector (CAN2).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
  • Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN2) terminal No. 8 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN2) terminal No. 19 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
<1 kΩ or more> Repair C-213 intermediate connector, or the wiring harness between joint connector (CAN2) and C-213 intermediate connector.
<Less than 1 kΩ > Go to Step 11.

STEP 11. M.U.T.-III CAN bus diagnostics [EPS-ECU connector disconnected].
caution Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(1)Disconnect EPS-ECU connector, 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 EPS-ECU connector.

Check the EPS-ECU connector, and repair if necessary. If the EPS-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 EPS-ECU connector, and repair if necessary. If the EPS-ECU connector is in good condition, replace the EPS-ECU.

STEP 13. Check CAN line between joint connector (CAN1) and the ETACS-ECU. Resistance measurement at joint connector (CAN1).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
  • Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN1) terminal No. 10 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN1) terminal No. 21 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
YES : <1 kΩ or more> Go to Step 14.
NO : <Less than 1 kΩ > Repair the wiring harness between joint connector (CAN1) and the ETACS-ECU connector.

STEP 14. Check the CAN line between joint connector (CAN1) and the combination meter. Resistance measurement at joint connector (CAN1).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN1) terminal No. 6 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN1) terminal No. 17 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
YES : <1 kΩ or more> Go to Step 17.
<Less than 1 kΩ > Go to Step 15.

STEP 15. M.U.T.-III CAN bus diagnostics [combination meter connector disconnected].
caution Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(1)Disconnect combination meter connector, 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 combination meter connector.

Check the combination meter connector, and repair if necessary. If the combination meter connector is in good condition, go to Step 16.

STEP 16. 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 combination meter connector, and repair if necessary. If the combination meter connector is in good condition, replace the combination meter.

STEP 17. Check the CAN line between joint connector (CAN1) and the SRS-ECU. Resistance measurement at joint connector (CAN1).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN1) terminal No. 4 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN1) terminal No. 15 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
<1 kΩ or more> Go to Step 20.
<Less than 1 kΩ > Go to Step 18.

STEP 18. M.U.T.-III CAN bus diagnostics [SRS-ECU connector disconnected].
caution Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(1)Disconnect combination meter connector, 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 SRS-ECU connector.

Check the SRS-ECU connector, and repair if necessary. If the SRS-ECU connector is in good condition, go to Step 19.

STEP 19. 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 SRS-ECU connector, and repair if necessary. If the SRS-ECU connector is in good condition, replace the SRS-ECU.

STEP 20. Check the CAN line between joint connector (CAN1) and the steering wheel sensor. Resistance measurement at joint connector (CAN1).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN1) terminal No. 3 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN1) terminal No. 14 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
<1 kΩ or more> Go to Step 23.
<Less than 1 kΩ > Go to Step 21.

STEP 21. M.U.T.-III CAN bus diagnostics [steering wheel sensor connector disconnected].
caution Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(1)Disconnect steering wheel sensor connector, 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, go to Step 22.

STEP 22. 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 steering wheel sensor connector, and repair if necessary. If the steering wheel sensor connector is in good condition, replace the steering wheel sensor. (Refer to GROUP 35C - Steering Wheel Sensor ).

STEP 23. Check the CAN line between joint connector (CAN1) and the diagnosis connector. Resistance measurement at joint connector (CAN1).
caution
  • A digital multimeter should be used. For details refer to service precautions.
  • The test wiring harness should be used. For details refer to service precautions.
  • Strictly observe the specified wiring harness repair procedure. For details refer to service precautions.
(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 service precautions.
Ensure that the negative battery terminal is disconnected.
(3)Resistance between joint connector (CAN1) terminal No. 8 (CAN_H) and body earth.
OK: 1 kΩ or more
(4)Resistance between joint connector (CAN1) terminal No. 19 (CAN_L) and body earth.
OK: 1 kΩ or more

Q. Is the check result normal?
<1 kΩ or more> Repair the C-213 intermediate connector, or the wiring harness between joint connector (CAN1) and the C-213 intermediate connector.
<Less than 1 kΩ > Repair the diagnosis connector, or the wiring harness between joint connector (CAN1) and the diagnosis connector.

STEP 24. M.U.T.-III CAN bus diagnostics [engine-ECU connector disconnected].
(1)Disconnect engine-ECU connector 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 26.

Check the engine-ECU connector, and repair if necessary. If the engine-ECU connector is in good condition, go to Step 25.

STEP 25. 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 26. M.U.T.-III CAN bus diagnostics [ETACS-ECU connector disconnected].
(1)Disconnect ETACS-ECU connector, 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 27.

STEP 27. 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.