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Diagnostic Item 23: Diagnose shorts in the ground to CAN-C-Mid.
 
 
cautionWhen servicing a CAN bus line, ground 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 CONDITIONS
The scan tool (M.U.T.-IIISE) 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 volt.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the wiring harness
  • Malfunction of the connector
  • Malfunction of the ETACS-ECU
  • Malfunction of the KOS&OSS-ECU <Vehicles with KOS>
  • Malfunction of the camera-ECU <Vehicles with multi around monitor>
  • Malfunction of the HUD <Vehicles with HUD>
  • Malfunction of the A/C controller assembly
  • Malfunction of the multivision display <Vehicles with smartphone link display audio>
  • Malfunction of the combination meter
  • Malfunction of the TCU <Vehicles with TCU up to 19 Model year>
  • Malfunction of the gateway-ECU (for TCU) <Vehicles with TCU from 20 Model year>
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the CAN-C-Mid. Resistance measurement at ETACS-ECU connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
noteThis inspection allows you to check that there is a short to ground in either CAN_H line or CAN_L line. Thus, in the following steps, check the CAN-C-Mid that is defective.
(1) Disconnect combination meter connector and ETACS-ECU connector, and measure the resistance at harness side of ETACS-ECU connector.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between ETACS-ECU connector terminal No.17 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between ETACS-ECU connector terminal No.16 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<Both of the measurement results show 1 kΩ or more> Go to Step 25.
<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-C-Mid between joint connector (CAN5) and the ETACS-ECU. Resistance measurement at joint connector (CAN5).
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.11 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.22 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 3.
<Less than 1 kΩ > Repair the wiring harness between joint connector (CAN5) and the ETACS-ECU connector.
 
STEP 3. Check the CAN-C-Mid between joint connector (CAN5) and the KOS&OSS-ECU. Resistance measurement at joint connector (CAN5).
noteSteps 3 to 5 are only for vehicles with KOS. On vehicles without it, go to Step 6.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.6 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.17 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 6.
<Less than 1 kΩ > Go to Step 4.
 
STEP 4. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [KOS&OSS-ECU connector disconnected]
(1) Disconnect KOS&OSS-ECU connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Repair the wiring harness between joint connector (CAN5) and the KOS&OSS-ECU connector.
Check the KOS&OSS-ECU connector, and repair if necessary. If the KOS&OSS-ECU connector is in good condition, go to Step 5.
 
STEP 5. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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 KOS&OSS-ECU connector, and repair if necessary. If the KOS&OSS-ECU connector is in good condition, replace the KOS&OSS-ECU.
 
STEP 6. Check the CAN-C-Mid between joint connector (CAN5) and the camera-ECU. Resistance measurement at joint connector (CAN5).
noteSteps 6 to 8 are only for vehicles with multi around monitor. On vehicles without it, go to Step 9.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.4 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.15 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 9.
<Less than 1 kΩ > Go to Step 7.
 
STEP 7. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [camera-ECU connector disconnected]
(1) Disconnect camera-ECU connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Check the intermediate connector, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN5) and the camera-ECU connector.
Check the camera-ECU connector, and repair if necessary. If the camera-ECU connector is in good condition, go to Step 8.
 
STEP 8. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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 camera-ECU connector, and repair if necessary. If the camera-ECU connector is in good condition, replace the camera-ECU.
 
STEP 9. Check the CAN-C-Mid between joint connector (CAN5) and the HUD. Resistance measurement at joint connector (CAN5).
noteSteps 9 to 11 are only for vehicles with HUD. On vehicles without it, go to Step 12.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.5 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.16 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 12.
<Less than 1 kΩ > Go to Step 10.
 
STEP 10. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [HUD connector disconnected]
(1) Disconnect HUD connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Repair the wiring harness between joint connector (CAN5) and the HUD connector.
Check the HUD connector, and repair if necessary. If the HUD connector is in good condition, go to Step 11.
 
STEP 11. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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 HUD connector, and repair if necessary. If the HUD connector is in good condition, replace the HUD.
 
STEP 12. Check the CAN-C-Mid between joint connector (CAN5) and the A/C controller assembly. Resistance measurement at joint connector (CAN5).
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.8 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.19 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 15.
<Less than 1 kΩ > Go to Step 13.
 
STEP 13. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [A/C controller assembly connector disconnected]
(1) Disconnect A/C controller assembly connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Repair the wiring harness between joint connector (CAN5) and the A/C controller assembly connector.
Check the A/C controller assembly connector, and repair if necessary. If the A/C controller assembly connector is in good condition, go to Step 14.
 
STEP 14. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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/C controller assembly connector, and repair if necessary. If the A/C controller assembly connector is in good condition, replace the A/C controller assembly.
 
STEP 15. Check the CAN-C-Mid between joint connector (CAN5) and the multivision display. Resistance measurement at joint connector (CAN5).
noteSteps 15 to 17 are only for vehicles with smartphone link display audio. On vehicles without it, go to Step 18.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.7 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.18 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 18.
<Less than 1 kΩ > Go to Step 16.
 
STEP 16. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [multivision display connector disconnected]
(1) Disconnect multivision display connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Repair the wiring harness between joint connector (CAN5) and the multivision display connector.
Check the multivision display connector, and repair if necessary. If the multivision display connector is in good condition, go to Step 17.
 
STEP 17. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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 multivision display connector, and repair if necessary. If the multivision display connector is in good condition, replace the multivision display.
 
STEP 18. Check the CAN-C-Mid between joint connector (CAN5) and the TCU. Resistance measurement at joint connector (CAN5).
noteSteps 18 to 20 are only for vehicles with TCU up to 19 Model year. On vehicles without it, go to Step 21.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.2 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.13 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 21.
<Less than 1 kΩ > Go to Step 19.
 
STEP 19. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [TCU connector disconnected]
(1) Disconnect TCU connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Repair the wiring harness between joint connector (CAN5) and the TCU connector.
Check the TCU connector, and repair if necessary. If the TCU connector is in good condition, go to Step 20.
 
STEP 20. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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 TCU connector, and repair if necessary. If the TCU connector is in good condition, replace the TCU.
 
STEP 21. Check the CAN-C-Mid between joint connector (CAN5) and the gateway-ECU (for TCU). Resistance measurement at joint connector (CAN5).
noteSteps 21 to 23 are only for vehicles with TCU from 20 Model year. On vehicles without it, go to Step 24.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.2 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.13 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 24.
<Less than 1 kΩ > Go to Step 22.
 
STEP 22. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [gateway-ECU (for TCU) connector disconnected]
(1) Disconnect gateway-ECU (for TCU) connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Check the intermediate connector, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN5) and the gateway-ECU (for TCU) connector.
Check the gateway-ECU (for TCU) connector, and repair if necessary. If the gateway-ECU (for TCU) connector is in good condition, go to Step 23.
 
STEP 23. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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 gateway-ECU (for TCU) connector, and repair if necessary. If the gateway-ECU (for TCU) connector is in good condition, replace the gateway-ECU (for TCU).
 
STEP 24. Check the CAN-C-Mid between joint connector (CAN5) and the combination meter. Resistance measurement at joint connector (CAN5).
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(3) Resistance between joint connector (CAN5) terminal No.10 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between joint connector (CAN5) terminal No.21 (CAN_L) and body ground
OK: 1 kΩ or more
(5)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Repair joint connector (CAN5).
<Less than 1 kΩ > Repair the wiring harness between joint connector (CAN5) and the combination meter connector.
 
STEP 25. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [combination meter connector disconnected]
(1) Disconnect combination meter connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
Go to Step 27.
Check the combination meter connector, and repair if necessary. If the combination meter connector is in good condition, go to Step 26.
 
STEP 26. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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 27. Scan tool (M.U.T.-IIISE) CAN bus diagnostics [ETACS-ECU connector disconnected]
(1) Disconnect ETACS-ECU connector and read all diagnosis with the scan tool (M.U.T.-IIISE).
(2) Confirm that all diagnosis reading results are as shown in the table.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Are all diagnosis reading results as shown in the table?
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 28.
 
STEP 28. Scan tool (M.U.T.-IIISE) CAN bus diagnostics (retest the system)
Diagnose CAN-C-Mid, and check if the scan tool (M.U.T.-IIISE) screen shows normal state.
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.