Diagnostic Item 3

DIAGNOSTIC ITEM 3: Abnormal Short Between The CAN-C Bus Lines.

CAUTION: When servicing a CAN bus line, ground yourself by touching a metal object such as an unpainted water pipe. If you fail to do so, a component connected to the CAN bus line may be damaged.

CAN-C Communication Circuit [M/T]:

CAN-C Communication Circuit [TC-SST] (Part 1):

CAN-C Communication Circuit [TC-SST] (Part 2):

FUNCTION
If a line-to-line short is present in the CAN-C lines, this diagnosis result will be set.

TROUBLE JUDGMENT CONDITIONS
If only diagnostic trouble code U0001 is set, the ETACS-ECU determines that there is a failure.

TROUBLESHOOTING HINTS
- Malfunction of the connector (joint connectors or ECU connectors improperly connected)
- Malfunction of the wiring harness (line-to-line short in the CAN-C main or sub bus lines)
- Malfunction of the ECU (ECU on CAN-C lines failed)

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
- MB992110: Power plant ECU check harness
- MB991997: ASC Check Harness

STEP 1. Check joint connector (CAN2) C-104, joint connector (CAN3) C-127 and joint connector (CAN4) A-14 [TC-SST] for loose, corroded or damaged terminals, or terminals pushed back in the connector.

CAUTION: The strand end of the twisted wire should be within 10 cm (4 inches) from the connector.

Q: Are joint connector (CAN2) C-104, joint connector (CAN3) C-127 and joint connector (CAN4) A-14 in good condition?

YES : Go to Step 2.

NO : Repair the damaged parts.

STEP 2. Check the wiring harness between joint connector (CAN2) C-104 and steering wheel senor connector C-209 for line-to-line short. Measure the resistance at joint connector (CAN2) C-104.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN2), and check that there is continuity at the harness side of joint connector (CAN2)







2. Check that there is continuity between joint connector (CAN2) terminals 7 and 20.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 3.

NO : Go to Step 11.

STEP 3. Check the wiring harness between joint connector (CAN2) C-104 and S-AWC-ECU connector C-46 for line-to-line short. Measure the resistance at joint connector (CAN2) C-104.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN2), and check that there is continuity at the harness side of joint connector (CAN2)







2. Check that there is continuity between joint connector (CAN2) terminals 5 and 16.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 4.

NO : Go to Step 12.

STEP 4. Check the wiring harness between joint connector (CAN2) C-104 and ETACS-ECU connector C-301 for line-to-line short. Measure the resistance at joint connector (CAN2) C-104.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN2), and check that there is continuity at the harness side of joint connector (CAN2)







2. Check that there is continuity between joint connector (CAN2) terminals 6 and 19.

OK: 120 ± 20 ohms

Q: Is the check result normal?

YES : Go to Step 5.

NO : Go to Step 13.

STEP 5. Check the wiring harness between joint connector (CAN3) C-127 and ASC-ECU connector A-05 for line-to-line short. Measure the resistance at joint connector (CAN3) C-127.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN3), and check that there is continuity at the harness side of joint connector (CAN3)







2. Check that there is continuity between joint connector (CAN3) terminals 6 and 19.

OK: No continuity

Q: Is the check result normal?

YES [M/T] : Go to Step 6.
YES [TC-SST] : Go to Step 7.

NO : Go to Step 14.

STEP 6. Check the wiring harness between joint connector (CAN3) C-127 and ECM connector B-10 [M/T] for line-to-line short. Measure the resistance at joint connector (CAN3) C-127.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN3), and check that there is continuity at the harness side of joint connector (CAN3)







2. Check that there is continuity between joint connector (CAN3) terminals 4 and 15.

OK: 120 ± 20 ohms

Q: Is the check result normal?

YES : Check intermediate connector C-131, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN2) C-104 and joint connector (CAN3) C-127.

NO : Go to Step 15.

STEP 7. Check the wiring harness between joint connector (CAN3) C-127 and shift lever connector for line-to-line short. Measure the resistance at joint connector (CAN3) C-127.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN3), and check that there is continuity at the harness side of joint connector (CAN3)







2. Check that there is continuity between joint connector (CAN3) terminals 7 and 20.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 8.

NO : Go to Step 16.

STEP 8. Check the wiring harness between joint connector (CAN4) A-14 and ECM connector B-10 [TC-SST] for line-to-line short. Measure the resistance at joint connector (CAN4) A-14.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN4), and check that there is continuity at the harness side of joint connector (CAN4)







2. Check that there is continuity between joint connector (CAN4) terminals 7 and 20.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 9.

NO : Go to Step 15.

STEP 9. Check the wiring harness between joint connector (CAN4) A-14 and transaxle assembly connector B-107 for line-to-line short. Measure the resistance at joint connector (CAN4) A-14.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

1. Disconnect joint connector (CAN4), and check that there is continuity at the harness side of joint connector (CAN4)







2. Check that there is continuity between joint connector (CAN4) terminals 6 and 19.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 10.

NO : Go to Step 17.

STEP 10. Check the wiring harness between joint connector (CAN3) C-127 and joint connector (CAN2) C-104 for line-to-line short. Measure the resistance at joint connector (CAN3) C-127.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

Disconnect joint connector (CAN3) and Disconnect joint connector (CAN2), and check that there is continuity at the harness side of joint connector (CAN3).







1. Check that there is continuity between joint connector (CAN3) terminals 5 and 16.

OK: No continuity

Q: Is the check result normal?

YES : Check intermediate connector A-13, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN3) C-127 and joint connector (CAN4) A-14.

NO : Check intermediate connector C-131, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN2) C-104 and joint connector (CAN3) C-127.

STEP 11. Using scan tool MB991958, diagnose the CAN bus line. (checking the steering wheel sensor for internal short)

CAUTION:
- Strictly observe the specified wiring harness repair procedure.
- To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Disconnect steering wheel sensor connector C-209







2. Connect scan tool MB991958 to the data link connector
3. Turn the ignition switch to the "ON" position.










4. Diagnose CAN bus lines, and check if the scan tool MB991958 screen is as shown in the figure.

OK: The display of the scan tool MB991958 is as shown in the figure.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES : Repair the wiring harness between steering wheel sensor connector C-209 and joint connector (CAN2) C-104.

NO : Check steering wheel sensor connector C-209, and repair if necessary. If the steering wheel sensor connector is in good condition, replace the steering wheel sensor.

STEP 12. Using scan tool MB991958, diagnose the CAN bus line. (checking the S-AWC-ECU for internal short)

CAUTION:
- Strictly observe the specified wiring harness repair procedure.
- To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Disconnect S-AWC-ECU connector C-46.







2. Connect scan tool MB991958 to the data link connector
3. Turn the ignition switch to the "ON" position.










4. Diagnose CAN bus lines, and check if the scan tool MB991958 screen is as shown in the figure.

OK: The display of the scan tool MB991958 is as shown in the figure.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES : Repair the wiring harness between S-AWC-ECU connector C-46 and joint connector (CAN2) C-104.

NO : Check S-AWC-ECU connector C-46, and repair if necessary. If the S-AWC-ECU connector is in good condition, replace the S-AWC-ECU.

STEP 13. Check the wiring harness between joint connector (CAN2) C-104 and ETACS-ECU connector C-301 for line-to-line short. Measure the resistance at joint connector (CAN2) C-104.

1. Disconnect joint connector (CAN2) and ETACS-ECU connector, and check that there is continuity at the harness side of joint connector (CAN2).







2. Check that there is continuity between joint connector (CAN2) terminals 6 and 19.

OK: No continuity

Q: Is the check result normal?

YES : Go to Step 18.

NO : Repair the wiring harness between ETACS-ECU connector C-301 and joint connector (CAN2) C-104.

STEP 14. Using scan tool MB991958, diagnose the CAN bus line. (checking the ASC-ECU for internal short)

CAUTION:
- Strictly observe the specified wiring harness repair procedure.
- To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Disconnect ASC-ECU connector A-05.







2. Connect scan tool MB991958 to the data link connector
3. Turn the ignition switch to the "ON" position.










4. Diagnose CAN bus lines, and check if the scan tool MB991958 screen is as shown in the figure.

OK: The display of the scan tool MB991958 is as shown in the figure.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES : Repair the wiring harness between ASC-ECU connector A-05 and joint connector (CAN3) C-127.

NO : Check ASC-ECU connector A-05, and repair if necessary. If the ASC-ECU connector is in good condition, replace the ASC-ECU.

STEP 15. Using scan tool MB991958, diagnose the CAN bus line. (checking the ECM for internal short)

CAUTION:
- Strictly observe the specified wiring harness repair procedure.
- To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Disconnect ECM connector B-10.







2. Connect scan tool MB991958 to the data link connector
3. Turn the ignition switch to the "ON" position.










4. Diagnose CAN bus lines, and check if the scan tool MB991958 screen is as shown in the figure.

OK: The display of the scan tool MB991958 is as shown in the figure.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES : Repair the wiring harness between ECM connector B-10 and joint connector (CAN3) C-127 [M/T], or check intermediate connector A-13, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between ECM connector B-10 and joint connector (CAN4) A-14 [TC-SST].

NO : Check ECM connector B-10, and repair if necessary. If the ECM connector is in good condition, replace the ECM.

STEP 16. Using scan tool MB991958, diagnose the CAN bus line. (checking the shift lever for internal short)

CAUTION:
- Strictly observe the specified wiring harness repair procedure.
- To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Disconnect shift lever connector C-27.







2. Connect scan tool MB991958 to the data link connector
3. Turn the ignition switch to the "ON" position.










4. Diagnose CAN bus lines, and check if the scan tool MB991958 screen is as shown in the figure.

OK: The display of the scan tool MB991958 is as shown in the figure.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES : Repair the wiring harness between shift lever connector C-27 and joint connector (CAN3) C-127.

NO : Check shift lever connector C-27, and repair if necessary. If the shift lever connector is in good condition, replace the shift lever.

STEP 17. Using scan tool MB991958, diagnose the CAN bus line. (checking the TC-SST-ECU for internal short)

CAUTION:
- Strictly observe the specified wiring harness repair procedure.
- To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Disconnect transaxle assembly connector B-107







2. Connect scan tool MB991958 to the data link connector
3. Turn the ignition switch to the "ON" position.










4. Diagnose CAN bus lines, and check if the scan tool MB991958 screen is as shown in the figure.

OK: The display of the scan tool MB991958 is as shown in the figure.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES : Repair the wiring harness between transaxle assembly connector B-107 and joint connector (CAN4) A-14.

NO : Check transaxle assembly connector B-107, and repair if necessary. If the transaxle assembly connector is in good condition, replace the transaxle assembly

STEP 18. Using scan tool MB991958, diagnose the CAN bus line.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.







1. Connect scan tool MB991958 to the data link connector
2. Turn the ignition switch to the "ON" position.










3. Diagnose CAN bus lines, and check if the scan tool screen is as shown in the illustration.

Q: Does the scan tool screen correspond to the illustration?

YES : The trouble can be an intermittent malfunction.

NO : Check ETACS-ECU connector C-301, and repair if necessary. If the ETACS-ECU connector is in good condition, replace the ETACS-ECU.