Diagnostic Item 8

DIAGNOSTIC ITEM 8: Diagnose when the scan tool cannot receive the data sent by TCM.

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.

CAN Communication Circuit Part 1:

CAN Communication Circuit Part 2:

FUNCTION
If the scan tool MB991958 cannot communicate with the TCM, this diagnosis result will be set.

TROUBLE JUDGEMENT CONDITIONS
If a communication flag is not set for the TCM, the ETACS-ECU determines that there is a failure.

TROUBLESHOOTING HINTS
- Malfunction of the connector [joint connector (CAN3) or TCM connector improperly connected]
- Malfunction of the wiring harness [open circuit between the TCM and the joint connector (CAN3), power supply circuit to the TCM]
- Malfunction of the TCM

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check joint connector (CAN2) C-04 and TCM connector C-38 for loose, corroded or damaged terminals, or terminals pushed back in the connector. The strand end of the twisted wire should be within 10 cm (4 inches) from the connector.

Q: Are joint connector (CAN2) C-04 and TCM connector C-38 in good condition?

YES: Go to Step 2.

NO: Repair the damaged parts.

STEP 2. Check the wiring harness between joint connector (CAN2) C-04 and TCM connector C-38.

CAUTION: Strictly observe the specified wiring harness repair procedure.

1. Disconnect joint connector (CAN2) C-04 and TCM connector C-38, and check the wiring harness.
2. Check the wiring harness between joint connector (CAN2) C-04 (terminal No.7) and TCM connector C-38 (terminal No. 4)
3. Check the wiring harness between joint connector (CAN2) C-04 (terminal No.20) and TCM connector C-38 (terminal No. 5)

Q: Is the wiring harness between joint connector (CAN2) C-04 and TCM connector C-38 in good condition?

YES: Check the power supply circuit of the TCM. Refer to A/T Mechanical, Troubleshooting.

NO: Repair the wiring harness between joint connector (CAN2) C-04 and TCM connector C-38.