Part 1

DIAGNOSTIC ITEM 7: Diagnose shorts between CAN_L and H 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.

Part 1:

Part 2:

TROUBLE JUDGMENT
A short circuit may be present between the CAN_L and H lines when the resistance between the CAN bus lines (CAN_L and H lines) is less than 2 ohms.

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 a 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 SRS-ECU may be defective
- The TPMS receiver may be defective
- The powertrain control module may be defective

DIAGNOSIS

Required Special Tool:
- MB991223: Harness Set




STEP 1. Check intermediate connector C-29 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: Is intermediate connector C-29 in good condition?

YES: Go to Step 2.

NO: Repair the damaged parts.

STEP 2. Check the lines between the CAN_L and H lines (communication line including ECUs) of the front wiring harness for a short circuit. Measure the resistance at intermediate connector C-29.

CAUTION: A digital multimeter should be used.

CAUTION: The test wiring harness should be used.




1. Disconnect intermediate connector C-29, and measure the resistance at the male side (at front wiring harness side).
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.




4. Measure the resistance between intermediate connector terminals 11 and 12.

OK: 120 ± 20 ohms

Q: Does the resistance measure 120 ± 20 ohms?

YES: If the resistance measures 120 ± 20 ohms, go to Step 3.

NO: If the resistance does not measure 120 ± 20 ohms> Go to STEP 27.







STEP 3. Check joint connector (3) C-02 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.

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 (3) C-02 in good condition?

YES: Go to Step 4.

NO: Repair the damaged parts. Replace the joint connector as necessary.

STEP 4. Check the CAN_L and H lines (communication lines including the combination meter) between joint connector (3) and the combination meter for a short circuit. Measure the resistance at joint connector (3) C-02.

CAUTION: A digital multimeter should be used.

CAUTION: The test wiring harness should be used.




1. Disconnect joint connector (3) C-02, and measure the resistance at the wiring harness side of joint connector (3) C-02.
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.




4. Measure the resistance between joint connector (3) terminals 4 and 15.

OK: 120 ± 20 ohms

Q: Does the resistance measure 120 ± 20 ohms?

YES: If the resistance measures 120 ± 20 ohms, go to Step 8.

NO: If the resistance does not measure 120 ± 20 ohms> Go to Step 5.




STEP 5. Check combination meter connector C-101 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: Is combination meter connector C-101 in good condition?

YES: Go to Step 6.

NO: Repair the damaged parts.

STEP 6. Check the CAN_L and H lines (communication lines only) between joint connector (3) and the combination meter for a short circuit. Measure the resistance at joint connector (3) C-02.

CAUTION: A digital multimeter should be used.

CAUTION: The test wiring harness should be used.




1. Disconnect joint connector (3) C-02 and combination meter connector C-101, and measure the resistance at the wiring harness side of joint connector (3) C-02.
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.




4. Measure the resistance between joint connector (3) terminals 4 and 15.

OK: 1 kohms or more

CAUTION: Strictly observe the specified wiring harness repair procedure.

Q: Does the resistance measure 1 kohms or more?

YES: If the resistance measures 1 kohms or more, go to Step 7.

NO: If the resistance measures less than 1 kohms, repair the wiring harness between joint connector (3) and the combination meter connector.

STEP 7. Check the combination meter for a short circuit. Measure the resistance at combination meter connector C-101.

CAUTION: A digital multimeter should be used.




1. Disconnect combination meter C-101, and measure the resistance at the component side of combination meter connector C-101.




2. Measure the resistance between combination meter connector terminals 14 and 15.

OK: 120 ± 20 ohms

Q: Does the resistance measure 120 ± 20 ohms?

YES: If the resistance measures 120 ± 20 ohms, diagnose CAN bus lines thoroughly by referring to DIAGNOSTIC ITEM 14.

NO: If the resistance does not measure 120 ± 20 ohms, replace the combination meter.

STEP 8. Check the CAN_L and H lines (communication lines including the ETACS-ECU) between joint connector (3) and the ETACS-ECU for a short circuit. Measure the resistance at joint connector (3) C-02.

CAUTION: A digital multimeter should be used.

CAUTION: The test wiring harness should be used.




1. Disconnect joint connector (3) C-02, and measure the resistance at the wiring harness side of joint connector (3) C-02.
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.




4. Measure the resistance between joint connector (3) terminals 5 and 16.

OK: 1 kohms or more

Q: Does the resistance measure 1 kohms or more?

YES: If the resistance measures 1 kohms or more, go to Step 12.

NO: If the resistance measures less than 1 kohms, go to Step 9.




STEP 9. 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 twisted wire should be within 10 cm (4 inches) from the connector.

Q: Is ETACS-ECU connector C-218 in good condition?

YES: Go to Step 10.

NO: Repair the damaged parts.

STEP 10. Check the CAN_L and H lines (communication lines only) between joint connector (3) and the ETACS-ECU for a short circuit. Measure the resistance at joint connector (3) C-02.

CAUTION: A digital multimeter should be used.

CAUTION: The test wiring harness should be used.







1. Disconnect joint connector (3) C-02 and ETACS-ECU connector C-218, and measure the resistance at the wiring harness side of joint connector (3) C-02.
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.




4. Measure the resistance between joint connector (3) terminals 5 and 16.

OK: 1 kohms or more

CAUTION: Strictly observe the specified wiring harness repair procedure.

Q: Does the resistance measure 1 kohms or more?

YES: If the resistance measures 1 kohms or more, go to Step 11.

NO: If the resistance measures less than 1 kohms, repair the wiring harness between joint connector (3) and the ETACS-ECU connector.