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DIAGNOSTIC ITEM 3: Abnormal short between the CAN-C bus lines.
 
 
cautionWhen 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.
 
 
 
 
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
  • MB991709: Wiring harness Set
STEP 1. Check joint connector (CAN2) C-202 and joint connector (CAN3) C-24 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
cautionThe strand end of the twisted wire should be within 10 cm (4 inches) from the connector. For details refer to .
Are joint connector (CAN2) C-202 and joint connector (CAN3) C-24 in good condition?
Go to Step 2.
Repair the damaged parts.
 
STEP 2. Check the wiring harness between joint connector (CAN2) C-202 and steering wheel sensor connector C-310 for line-to-line short. Measure the resistance at joint connector (CAN2) C-202.
cautionDisconnect the negative battery terminal. For details refer to .
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 (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 9 and 20.
OK: No continuity
Is the check result normal?
<FWD> : Go to Step 4.
<AWD> : Go to Step 3.
Go to Step 9.
 
STEP 3. Check the wiring harness between joint connector (CAN2) C-202 and AWD-ECU connector C-228 for line-to-line short. Measure the resistance at joint connector (CAN2) C-202.
(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 8 and 19.
OK: No continuity
Is the check result normal?
Go to Step 4.
Go to Step 10.
 
STEP 4. Check the wiring harness between joint connector (CAN3) C-24 and ECM connector B-27 for line-to-line short. Measure the resistance at joint connector (CAN3) C-24.
(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 18.
OK: No continuity
Is the check result normal?
<CVT> : Go to Step 5.
<M/T> : Go to Step 6.
Go to Step 11.
 
STEP 5. Check the wiring harness between joint connector (CAN3) C-24 and TCM connector C-131 for line-to-line short. Measure the resistance at joint connector (CAN3) C-24.
(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 5 and 16.
OK: No continuity
Is the check result normal?
Go to Step 6.
Go to Step 12.
 
STEP 6. Check the wiring harness between joint connector (CAN3) C-24 and ASC-ECU connector A-03 for line-to-line short. Measure the resistance at joint connector (CAN3) C-24.
(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 8 and 19.
OK: No continuity
Is the check result normal?
Go to Step 7.
Go to Step 13.
 
STEP 7. Check the wiring harness between joint connector (CAN3) C-24 and electric power steering-ECU connector C-144 for a short to ground. Measure the resistance at joint connector (CAN3) C-24.
cautionDisconnect the negative battery terminal. For details refer to .
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 (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 9 and 20.
OK: No continuity
Do all the resistances measure 1 kilo ohm or more?
Go to Step 8.
Go to Step 14.
 
STEP 8. Check the wiring harness between joint connector (CAN2) C-202 and ETACS-ECU connector C-411 for line-to-line short. Measure the resistance at joint connector (CAN2) C-202.
(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 11 and 22.
OK: No continuity
Is the check result normal?
Check intermediate connector C-128, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN2) C-202 and joint connector (CAN3) C-24.
Go to Step 15.
 
STEP 9. Using scan tool MB991958, diagnose the CAN bus line. (checking the steering wheel sensor for internal short)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
cautionTo 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-310.
(2) Connect scan tool MB991958 to the data link connector. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Does scan tool MB991958 screen correspond to the illustration?
Repair the wiring harness between steering wheel sensor connector C-310 and joint connector (CAN2) C-202.
Check steering wheel sensor connector C-310, and repair if necessary. If the steering wheel sensor connector is in good condition, replace the steering wheel sensor.
 
STEP 10. Using scan tool MB991958, diagnose the CAN bus line. (checking the AWD-ECU for internal short)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
cautionTo 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 AWD-ECU connector C-228.
(2) Connect scan tool MB991958 to the data link connector. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Does scan tool MB991958 screen correspond to the illustration?
Check intermediate connectors C-27, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between AWD-ECU connector C-228 and joint connector (CAN2) C-202.
Check AWD-ECU connector C-228, and repair if necessary. If the AWD-ECU connector is in good condition, replace the AWD-ECU.
 
STEP 11. Using scan tool MB991958, diagnose the CAN bus line. (checking the ECM for internal short)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
cautionTo 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-27.
(2) Connect scan tool MB991958 to the data link connector. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Does scan tool MB991958 screen correspond to the illustration?
Repair the wiring harness between ECM connector B-27 and joint connector (CAN3) C-24.
Check ECM connector B-27, and repair if necessary. If the ECM connector is in good condition, replace the ECM.
 
STEP 12. Using scan tool MB991958, diagnose the CAN bus line. (checking the TCM for internal short)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
cautionTo 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 TCM connector C-131.
(2) Connect scan tool MB991958 to the data link connector. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Does scan tool MB991958 screen correspond to the illustration?
Repair the wiring harness between TCM connector C-131 and joint connector (CAN3) C-24.
Check TCM connector C-131, and repair if necessary. If the TCM connector is in good condition, replace the TCM.
 
STEP 13. Using scan tool MB991958, diagnose the CAN bus line. (checking the ASC-ECU for internal short)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
cautionTo 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-03.
(2) Connect scan tool MB991958 to the data link connector. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Does scan tool MB991958 screen correspond to the illustration?
Repair the wiring harness between ABS-ECU connector ASC-ECU connector A-03 and joint connector (CAN3) C-24.
Check ASC-ECU connector A-03 , and repair if necessary. If the ASC-ECU connector is in good condition, replace the ASC-ECU.
 
STEP 14. Using scan tool MB991958, diagnose the CAN bus line. (checking the electric power steering-ECU for internal short)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
cautionTo 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 electric power steering connector C-144.
(2) Connect scan tool MB991958 to the data link connector. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Does scan tool MB991958 screen correspond to the illustration?
Check intermediate connectors C-146, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between electric power steering-ECU connector C-144 and joint connector (CAN3) C-24.
Check electric power steering-ECU connector C-144, and repair if necessary. If the electric power steering-ECU connector is in good condition, replace the electric power steering-ECU.
 
STEP 15. Check the wiring harness between joint connector (CAN2) C-202 and ETACS-ECU connector C-411 for line-to-line short. Measure the resistance at joint connector (CAN2) C-202.
(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 11 and 22.
OK: No continuity
Is the check result normal?
Go to Step 16.
Repair the wiring harness between joint connector (CAN2) C-202 and ETACS-ECU connector C-411.
 
STEP 16. Using scan tool MB991958, diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958 to the data link connector. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Does the scan tool 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 ).
Replace the ETACS-ECU.