Part 1
DIAGNOSTIC ITEM 2: Diagnose shorts in the power supply to CAN bus linePart 1:
Part 2:
TROUBLE JUDGMENT
A short to the power supply may be present when the voltage between the CAN bus line (CAN_L or CAN_H) and body ground is more than 4.0 V. In this condition, an abnormal voltage may be measured at CAN_L and CAN_H lines.
COMMENTS ON TROUBLE SYMPTOM
The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or an ECU may be defective.
TROUBLESHOOTING HINTS
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The ETACS-ECU may be defective
- The combination meter may be defective
- The A/C-ECU may be defective
- The ABS-ECU may be defective
- The powertrain control module may be defective
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB991970: ABS Check Harness
STEP 1. Check powertrain control module connector B-18, combination meter connector C-102 and data link connector C-121 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
CAUTION: The strand end of the twist wire should be within 10 cm from the connector. For details refer to "Service Precautions".
Q: Are powertrain control module connector B-18, combination meter connector C-102 and data link connector C-121 in good condition?
YES: Go to Step 2.
NO: Repair the damaged parts.
STEP 2. Check the CAN_H-side bus line (communication line including ECUs) for a short to the power supply. Measure the voltage at data link connector C-121.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect powertrain control module connector B-18 and combination meter connector C-102, and measure the voltage at the harness side of data link connector C-121.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between data link connector terminal 6 and body ground.
OK: 4.0 V or less
Q: Does the voltage measure 4.0 V or less?
YES:
NO:
STEP 3. Check the CAN_L-side bus line (communication line including ECUs) for a short to the power supply. Measure the voltage at data link connector C-121.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect powertrain control module connector B-18 and combination meter connector C-102, and measure the voltage at the harness side of data link connector C-121.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between data link connector terminal 14 and body ground.
OK: 4.0 V or less
Q: Does the voltage measure 4.0 V or less?
YES:
NO:
STEP 4. Check intermediate connector C-31 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
CAUTION: The strand end of the twist wire should be within 10 cm from the connector. For details refer to "Service Precautions".
Q: Is intermediate connector C-31 in good condition?
YES: Go to Step 5.
NO: Repair the damaged parts.
STEP 5. Check the CAN_H-side bus line (communication line including ECUs) of the front wiring harness for a short to the power supply. Measure the voltage at intermediate connector C-31.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect intermediate connector C-31, and measure the voltage at the male side (at front wiring harness side).
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between intermediate connector C-31 terminal 11 and body ground.
OK: 4.0 V or less
Q: Does the voltage measure 4.0 V or less?
YES:
NO:
STEP 6. Check joint connector 4. C-101 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
CAUTION: The strand end of the twist wire should be within 10 cm from the connector. For details refer to "Service Precautions".
Check the joint connector at the wiring harness side for loose, corroded or damaged terminals, or terminals pushed back in the connector, and also check the short pin behind the connector for corrosion, deformation and delamination.
Q: Is joint connector 4. C-101 in good condition?
YES: Go to Step 7.
NO: Repair the damaged parts. Replace the joint connector as necessary.
STEP 7. Check the CAN_H line (communication line including the combination meter) between joint connector 4. and the combination meter for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect joint connector 4. C-101, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 15 and body ground.
OK: 4.0 V or less
Q: Does the voltage measure 4.0 V or less?
YES:
NO:
STEP 8. Check the CAN_H line (communication line only) between joint connector 4. and the combination meter connector for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect joint connector 4. C-101 and combination meter connector C-102, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 15 and body ground.
OK: 1.0 V or less
CAUTION: Strictly observe the specified wiring harness repair procedure. For details refer to "Precautions On How To Repair The CAN Bus Lines".
Q: Does the voltage measure 1.0 V or less?
YES:
NO:
STEP 9. Check the CAN_H line (communication line including the ETACS-ECU) between joint connector 4. and the ETACS-ECU connector for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect joint connector 4. C-101, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 17 and body ground.
OK: 4.0 V or less
Q: Does the voltage measure 4.0 V or less?
YES:
NO:
STEP 10. Check ETACS-ECU connector C-218 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
CAUTION: The strand end of the twist wire should be within 10 cm from the connector. For details refer to "Service Precautions".
Q: Is ETACS-ECU connector C-218 in good condition?
YES: Go to Step 11.
NO: Repair the damaged parts.
STEP 11. Check the CAN_H line (communication line only) between joint connector 4. and ETACS-ECU connector for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect joint connector 4. C-101 and ETACS-ECU connector C-218, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 17 and body ground.
OK: 1.0 V or less
CAUTION: Strictly observe the specified wiring harness repair procedure. For details refer to "Precautions On How To Repair The CAN Bus Lines".
Q: Does the voltage measure 1.0 V or less?
YES:
NO:
STEP 12. Check the CAN_H line (communication line including the A/C-ECU) between joint connector 4. and the A/C-ECU connector for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect joint connector 4. C-101, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 18 and body ground.
OK: 4.0 V or less
Q: Does the voltage measure 4.0 V or less?
YES:
NO:
STEP 13. Check A/C-ECU connector C-16 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
CAUTION: The strand end of the twist wire should be within 10 cm from the connector. For details refer to "Service Precautions".
Q: Is A/C-ECU connector C-16 in good condition?
YES: Go to Step 14.
NO: Repair the damaged parts.
STEP 14. Check the CAN_H line (communication line only) between joint connector 4. and A/C-ECU connector for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect joint connector 4. C-101 and A/C-ECU connector C-16, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 18 and body ground.
OK: 1.0 V or less
CAUTION: Strictly observe the specified wiring harness repair procedure. For details refer to "Precautions On How To Repair The CAN Bus Lines".
Q: Does the voltage measure 1.0 V or less?
YES:
NO:
STEP 15. Check the CAN_H line (communication line only) between joint connector 4. and the data link connector for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect joint connector 4. C-101, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 16 and body ground.
OK: 1.0 V or less
CAUTION: Strictly observe the specified wiring harness repair procedure. For details refer to "Precautions On How To Repair The CAN Bus Lines".
Q: Does the voltage measure 1.0 V or less?
YES:
NO:
STEP 16. Check the CAN_H line (communication line only) between intermediate connector C-31 and joint connector 4. for a short to the power supply. Measure the voltage at joint connector 4. C-101.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect intermediate connector C-31 and joint connector 4. C-101, and measure the voltage at the wiring harness side of joint connector 4. C-101.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between joint connector 4. terminal 20 and body ground.
OK: 1.0 V or less
CAUTION: Strictly observe the specified wiring harness repair procedure. For details refer to "Precautions On How To Repair The CAN Bus Lines".
Q: Does the voltage measure 1.0 V or less?
YES:
NO:
STEP 17. Check ABS-ECU connector A-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
CAUTION: The strand end of the twist wire should be within 10 cm from the connector. For details refer to "Service Precautions".
Q: Is ABS-ECU connector A-02 in good condition?
YES: Go to Step 18.
NO: Repair the damaged parts.
STEP 18. Check the CAN_H line (communication line only) between intermediate connector C-31 and ABS-ECU connector for a short to the power supply. Measure the voltage at intermediate connector C-31.
CAUTION: A digital multimeter should be used. For details refer to "Service Precautions".
CAUTION: The test wiring harness should be used. For details refer to "Service Precautions".
1. Disconnect intermediate connector C-31 and ABS-ECU connector A-02, and measure the voltage at the male side of intermediate connector C-31 (at front wiring harness side).
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between intermediate connector C-31 terminal 11 and body ground.
OK: 1.0 V or less
CAUTION: Strictly observe the specified wiring harness repair procedure. For details refer to "Precautions On How To Repair The CAN Bus Lines".
Q: Does the voltage measure 1.0 V or less?
YES:
NO: