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DIAGNOSTIC ITEM 16: Diagnose when the scan tool cannot receive the data sent by ECM.
 
 
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 ECM, this diagnosis result will be set.
 
 
TROUBLE JUDGMENT CONDITIONS
If a communication flag is not set for the ECM, the ETACS-ECU determines that there is a failure.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the connector [joint connector (CAN3) or ECM connector improperly connected]
  • Malfunction of the wiring harness [open circuit between the ECM and the joint connector (CAN3), power supply circuit to the ECM]
  • Malfunction of the ECM
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check joint connector (CAN3) C-24 and ECM connector B-27 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 ECM connector B-27 in good condition?
Go to Step 2.
Repair the damaged parts.
 
STEP 2. Check the wiring harness between joint connector (CAN3) C-24 and ECM connector B-27 for open circuit.
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
(1) Disconnect joint connector (CAN3) C-24 and ECM connector B-27, and check the wiring harness.
(2) Check the wiring harness between joint connector (CAN3) C-24 (terminal No.7) and ECM connector B-27 (terminal No.90)
OK: Continuity exists (2 ohms or less)
(3) Check the wiring harness between joint connector (CAN3) C-24 (terminal No.18) and ECM connector B-27 (terminal No.91)
OK: Continuity exists (2 ohms or less)
Is the wiring harness between joint connector (CAN3) C-24 and ECM connector B-27 in good condition?
Check the power supply circuit of the ECM. Refer to GROUP 13A, Diagnosis <2.0L ENGINE> or GROUP 13C, Diagnosis <2.4L ENGINE>.
Repair the wiring harness between joint connector (CAN3) C-24 and ECM connector B-27.