Diagnosis Item 3: Abnormal short between the CAN-C bus lines
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
If a line-to-line short is present in the CAN-C lines, this diagnosis result will be set.
TRUBLE JUDGEMENT CONDITIONS
If only diagnosis 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)
The strand end of the twist wire should be within 10 cm from the connector. For details refer to .
Q.
Is the check result normal?
YES <vehicles without ASC> : Go to Step 3.
YES <vehicles with ASC> : Go to Step 2.
NO (connector is not normal.) : Repair the defective connector.
STEP 2. Check the wiring harness between C-209 steering wheel sensor connector and C-04 joint connector (CAN2) for line-to-line short.
caution
A digital multimeter should be used. For details refer to .
The 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.
(2)Check that there is continuity between C-04 joint connector (CAN2) terminal Nos.4 and 5. OK: No continuity
Q.
Is the check result normal?
Go to Step 3.
Go to Step 7.
STEP 3. Check the wiring harness between C-130 4WD-ECU connector and C-04 joint connector (CAN2) for line-to-line short.
caution
A digital multimeter should be used. For details refer to .
The 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.
(2)Check that there is continuity between C-04 joint connector terminal Nos.5 and 16. OK: No continuity
Q.
Is the check result normal?
Go to Step 4.
Go to Step 8.
STEP 4. Check the wiring harness between B-06 engine-ECU connector and C-01 joint connector (CAN3) for line-to-line short.
caution
A digital multimeter should be used. For details refer to .
The 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.
(2)Check that there is continuity between C-01 joint connector terminal Nos.4 and 15. OK: No continuity
Q.
Is the check result normal?
Go to Step 5.
Go to Step 9.
STEP 5. Check the wiring harness between A-02 ABS-ECU connector <vehicles without ASC> or A-03 ASC-ECU connector <vehicles with ASC> and C-01 joint connector (CAN3) for line-to-line short.
caution
A digital multimeter should be used. For details refer to .
The 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.
(2)Check that there is continuity between C-01 joint connector terminal Nos.6 and 19. OK: No continuity
Q.
Is the check result normal?
Go to Step 6.
Go to Step 10.
STEP 6. Check the wiring harness between C-301 ETACS-ECU connector and C-04 joint connector (CAN2) for line-to-line short.
caution
A digital multimeter should be used. For details refer to .
The test wiring harness should be used. For details refer to .
Strictly observe the specified wiring harness repair procedure. For details refer to .
(1)Disconnect joint connector (CAN2), and check that there is continuity at the harness side.
(2)Check that there is continuity between C-04 joint connector terminal Nos.6 and 19 <LHD> or 7 and 20 <RHD>. OK: No continuity
Q.
Is the check result normal?
Check C-37 intermediate connector, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between C-04 joint connector (CAN2) and C-01 joint connector (CAN3).
Go to Step 11.
STEP 7. M.U.T.-III CAN bus diagnostics (checking the steering wheel sensor for internal short)
caution
Strictly observe the specified wiring harness repair procedure. For details refer to .
Disconnect C-209 steering wheel sensor connector, and diagnose the CAN bus line.
OK: The display of the M.U.T.-III is as shown in the figure.
Q.
Does M.U.T.-III screen correspond to the illustration?
Repair the wiring harness between C-209 steering wheel sensor connector and C-04 joint connector (CAN2).
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.
STEP 8. M.U.T.-III CAN bus diagnostics (checking the 4WD-ECU for internal short)
caution
Strictly observe the specified wiring harness repair procedure. For details refer to .
Disconnect C-130 4WD-ECU connector, and diagnose the CAN bus line.
OK: The display of the M.U.T.-III is as shown in the figure.
Q.
Does M.U.T.-III screen correspond to the illustration?
Check C-37 intermediate connector, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between C-130 4WD-ECU connector and C-04 joint connector (CAN2).
Check the 4WD-ECU connector, and repair if necessary. If the 4WD-ECU connector is in good condition, replace the 4WD-ECU.
STEP 9. M.U.T.-III CAN bus diagnostics (checking the engine-ECU for internal short)
caution
Strictly observe the specified wiring harness repair procedure. For details refer to .
Disconnect B-06 engine-ECU connector, and diagnose the CAN bus line.
OK: The display of the M.U.T.-III is as shown in the figure.
Q.
Does M.U.T.-III screen correspond to the illustration?
Repair the wiring harness between B-06 engine-ECU connector and C-01 joint connector (CAN3).
Check the engine-ECU connector, and repair if necessary. If the engine-ECU connector is in good condition, replace the engine-ECU.
STEP 10. M.U.T.-III CAN bus diagnostics (checking the ABS-ECU <vehicles without ASC> or ASC-ECU <vehicles with ASC> for internal short)
caution
Strictly observe the specified wiring harness repair procedure. For details refer to .
Disconnect A-02 ABS-ECU connector <vehicles without ASC> or A-03 ASC-ECU connector <vehicles with ASC>, and diagnose the CAN bus line.
OK: The display of the M.U.T.-III is as shown in the figure.
Q.
Does M.U.T.-III screen correspond to the illustration?
Repair the wiring harness between A-02 ABS-ECU connector <vehicles without ASC> or A-03 ASC-ECU connector <vehicles with ASC> and C-01 joint connector (CAN3).
Check the ABS-ECU <vehicles without ASC> or ASC-ECU <vehicles with ASC> connector, and repair if necessary. If the ABS-ECU <vehicles without ASC> or ASC-ECU <vehicles with ASC> connector is in good condition, replace the ABS-ECU <vehicles without ASC> or ASC-ECU <vehicles with ASC>.
STEP 11. Check the wiring harness between C-301 ETACS-ECU connector and C-04 joint connector (CAN2) for line-to-line short.
caution
A digital multimeter should be used. For details refer to .
The test wiring harness should be used. For details refer to .
Strictly observe the specified wiring harness repair procedure. For details refer to .
(1)Disconnect the ETACS-ECU connector and the joint connector (CAN2), and check that there is continuity at the harness side.
(2)Check that there is continuity between C-04 joint connector terminal Nos.6 and 19 <LHD> or 7 and 20 <RHD>. OK: No continuity
Q.
Is the check result normal?
Go to Step 12.
Repair the wiring harness between C-301 ETACS-ECU connector and C-04 joint connector (CAN2).
STEP 12. Trouble symptom check
Diagnose the CAN bus line, and check that normal condition is displayed.
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 is in good condition, replace the ETACS-ECU.
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