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DIAGNOSTIC ITEM 27: Diagnose the ETACS-ECU, joint connector (CAN1) or lines between ETACS-ECU and joint connector (CAN1).


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.






FUNCTION


If a failure is present in the wiring harness wires between the ETACS-ECU connector, the joint connector (CAN1), the ETACS-ECU connector and the joint connector (CAN1), this diagnosis result will be set.

TROUBLE JUDGEMENT CONDITIONS


If a communication flag is set for none of the ECUs on the CAN-B line, the ETACS-ECU determines that there is a failure.

TROUBLESHOOTING HINTS



DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe

STEP 1. Check joint connector (CAN1) C-06 and EATCS-ECU connector C-301 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. For details refer to .

Q. Are joint connector (CAN1) C-06 and ETACS-ECU connector C-301 in good condition?
Go to Step 2.
Repair the damaged parts.

STEP 2. Check the wiring harness between joint connector (CAN1) C-06 and ETACS-ECU connector C-301 for open circuit.
caution Strictly observe the specified wiring harness repair procedure. For details refer to .
(1)Disconnect joint connector (CAN1) C-06 and ETACS-ECU connector C-301, and check the wiring harness.

(2)Check the wiring harness between joint connector (CAN1) C-06 (terminal 6) and ETACS-ECU connector C-301 (terminal 6)
OK: Continuity exists (2 Ω or less)

(3)Check the wiring harness between joint connector (CAN1) C-06 (terminal 19) and ETACS-ECU connector C-301 (terminal 7)
OK: Continuity exists (2 Ω or less)

Q. Is the wiring harness between joint connector (CAN1) C-06 and ETACS-ECU connector C-301 in good condition?

Go to Step 3.

Repair the wiring harness between joint connector (CAN1) C-06 and ETACS-ECU connector C-301.

STEP 3. Using scan tool MB991958, diagnose the CAN bus line. (trouble symptom check)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .
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 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?

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.