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DIAGNOSTIC ITEM 14: Diagnose when the scan tool cannot receive the data sent by ASC-ECU.
 
 
cautionWhen 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 the scan tool MB991958 cannot communicate with the ASC-ECU, this diagnosis result will be set.
 
 
TROUBLE JUDGMENT CONDITIONS
If a communication flag is not set for the ASC-ECU, the ETACS-ECU determines that there is a failure.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the connector [joint connector (CAN3) or ASC-ECU connector improperly connected]
  • Malfunction of the wiring harness [open circuit between the ASC-ECU and the joint connector (CAN3), power supply circuit to the ASC-ECU]
  • Malfunction of the ASC-ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
  • MB991709: Wiring harness Set
STEP 1. Check joint connector (CAN3) C-24 and ASC-ECU connector A-03 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
cautionThe strand end of the twisted wire should be within 10 cm (4 inches) from the connector. For details refer to .
Are joint connector (CAN3) C-24 and ASC-ECU connector A-03 in good condition?
Go to Step 2.
Repair the damaged parts.
 
STEP 2. Check the wiring harness between joint connector (CAN3) C-24 and ASC-ECU connector A-03 for open circuit.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
(1) Disconnect joint connector (CAN3) C-24 and ASC-ECU connector A-03, and check the wiring harness.
(2) Check the wiring harness between joint connector (CAN3) C-24 (terminal No.8) and ASC-ECU connector A-03 (terminal No.11)
OK: Continuity exists (2 ohms or less)
(3) Check the wiring harness between joint connector (CAN3) C-24 (terminal No.19) and ASC-ECU connector A-03 (terminal No.10)
OK: Continuity exists (2 ohms or less)
Is the wiring harness between joint connector (CAN3) C-24 and ASC-ECU connector A-03 in good condition?
Check the power supply circuit of the ASC-ECU. Refer to GROUP 35C, Diagnosis <ASC-ECU>.
Repair the wiring harness between joint connector (CAN3) C-24 and ASC-ECU connector A-03.