Part 3

DIAGNOSTIC ITEM 24: Short to power supply or ground in both CAN_H and CAN_L lines of the CAN-B bus lines. (Continued)

STEP 23. Using scan tool MB991958, diagnose the CAN bus line. (checking the KOS-ECU for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect KOS-ECU connector C-05.





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and KOS-ECU connector C-05.

NO Check KOS-ECU connector C-05, and repair if necessary. If the KOS-ECU connector is in good condition, replace the KOS-ECU.

STEP 24. Using scan tool MB991958, diagnose the CAN bus line. (checking the WCM for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect WCM connector C-07.





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and WCM connector C-07.

NO Check WCM connector C-07, and repair if necessary. If the WCM connector is in good condition, replace the WCM.

STEP 25. Using scan tool MB991958, diagnose the CAN bus line. (checking the SRS-ECU for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect SRS-ECU connector C-37.





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and SRS-ECU connector C-37.

NO Check SRS-ECU connector C-37, and repair if necessary. If the SRS-ECU connector is in good condition, replace the SRS-ECU.

STEP 26. Using scan tool MB991958, diagnose the CAN bus line. (checking the occupant classification-ECU for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect occupant classification-ECU connector D-39-2.





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and occupant classification-ECU connector D-39-2.

NO Check occupant classification-ECU connector D-39-2, and repair if necessary. If the occupant classification-ECU connector is in good condition, replace the occupant classification-ECU.

STEP 27. Using scan tool MB991958, diagnose the CAN bus line. (checking the A/C-ECU [vehicles with A/C] or heater control unit [vehicles without A/C]
for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect A/C-ECU connector C-22 [vehicles with A/C] or heater control unit connector C-53 [vehicles without A/C].





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and A/C-ECU connector C-22 [vehicles with A/C] or heater control unit connector C-53 [vehicles without A/C].

NO Check A/C-ECU connector C-22 [vehicles with A/C] or heater control unit connector C-53 [vehicles without A/C], and repair if necessary. If the A/C-ECU connector [vehicles with A/C] or heater control unit connector [vehicles without A/C] is in good condition, replace the A/C-ECU [vehicles with A/C] or heater control unit [vehicles without A/C].

STEP 28. Using scan tool MB991958, diagnose the CAN bus line. (checking the radio and CD player or CD changer for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect radio and CD player or CD changer connector C-107.





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and radio and CD player or CD changer connector C-107.

NO Check radio and CD player or CD changer connector C-107, and repair if necessary.
If the radio and CD player or CD changer connector is in good condition, replace the radio and CD player or CD changer.

STEP 29. Using scan tool MB991958, diagnose the CAN bus line. (checking the CAN box unit for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect CAN box unit connector C-15.





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and CAN box unit connector C-15.

NO Check CAN box unit connector C-15, and repair if necessary. If the CAN box unit connector is in good condition, replace the CAN box unit.

STEP 30. Using scan tool MB991958, diagnose the CAN bus line. (checking the satellite radio tuner for internal failure)

CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions When CAN Bus Line(s) are Repaired.

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)Disconnect satellite radio tuner connector C-18.





(2)Connect scan tool MB991958 to the data link connector.
(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.

Q. Does scan tool MB991958 screen correspond to the illustration?

YES Repair the wiring harness between joint connector (CAN1) C-105 and satellite radio tuner connector C-18.

NO Check satellite radio tuner connector C-18, and repair if necessary. If the satellite radio tuner connector is in good condition, replace the satellite radio tuner.

STEP 31. 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 Precautions When CAN Bus Line(s) are Repaired.

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?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).

NO Check the ETACS-ECU connector C-301, and repair if necessary. If the ETACS-ECU connector is in good condition, replace the ETACS-ECU.