Diagnosis Item 22: Diagnose when the M.U.T.-III cannot receive the data sent by CAN box unit <vehicles with MMCS>


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



TROUBLE JUDGEMENT CONDITIONS



TROUBLESHOOTING HINTS



  • Malfunction of the connector [joint connector (CAN1) or CAN box unit connector improperly connected]
  • Malfunction of the wiring harness [open circuit between the CAN box unit connector and the joint connector (CAN1), power supply circuit of the CAN box unit]
  • Malfunction of the CAN box unit

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-04 joint connector (CAN1) and C-54 CAN box unit connector
caution 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?
Go to Step 2.
Repair the defective connector.

STEP 2. Check the wiring harness between C-54 CAN box unit connector and C-04 joint connector (CAN1)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .
Disconnect CAN box unit connector and joint connector (CAN1), and check the following wiring harness for open circuit
(1)The wiring harness between C-54 CAN box unit connector terminal No.8 and C-04 joint connector (CAN1) terminal No.7 <CAN_H>
OK: Continuity exists (2 Ω or less)
(2)The wiring harness between C-54 CAN box unit connector terminal No.9 and C-04 joint connector (CAN1) terminal No.20 <CAN_L>
OK: Continuity exists (2 Ω or less)
note Check C-139 intermediate connector, and repair if necessary.

Q. Is the check result normal?
Check the power supply circuit of the CAN box unit. Refer to GROUP 54A - MMCS - Troubleshooting .
Repair the wiring harness.