Diagnostic Item 10

DIAGNOSTIC ITEM 10: Diagnose When The Scan Tool Cannot Receive The Data Sent By ECM.

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-C Communication Circuit [M/T]:

CAN-C Communication Circuit [TC-SST] (Part 1):

CAN-C Communication Circuit [TC-SST] (Part 2):

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) [M/T], joint connector (CAN4) [TC-SST], ECM connector or intermediate connector [TC-SST] improperly connected]
- Malfunction of the wiring harness [open circuit between the ECM connector and the joint connector (CAN3) [M/T] or the joint connector (CAN4) [TC-SST], power supply circuit to the ECM]
- Malfunction of the ECM

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB992110: Power plant ECU check harness

STEP 1. Check joint connector (CAN3) C-127 [M/T], joint connector (CAN4) A-14 [TC-SST], ECM connector B-10 and intermediate connector A-13 [TC-SST] for loose, corroded or damaged terminals, or terminals pushed back in the connector.

CAUTION: The strand end of the twisted wire should be within 10 cm (4 inches) from the connector.

Q: Are joint connector (CAN3) C-127 [M/T], joint connector (CAN4) A-14 [M/T], ECM connector B-10 and intermediate connector A-13 [TC-SST] in good condition?

YES : Go to Step 2.

NO : Repair the damaged parts.

STEP 2. Check the wiring harness between joint connector (CAN3) C-127 [M/T] or joint connector (CAN4) A-14 [TC-SST] and ECM connector B-10.

CAUTION: Strictly observe the specified wiring harness repair procedure.

1. Disconnect joint connector (CAN3) C-127 and ECM connector B-10, and check the wiring harness







2. Check the wiring harness between joint connector (CAN3) C-127 (terminal 4) and ECM connector B-10 (terminal 90) [M/T]

OK: Continuity exists (2 ohms or less)







3. Check the wiring harness between joint connector (CAN3) C-127 (terminal 15) and ECM connector B-10 (terminal 91) [M/T]

OK: Continuity exists (2 ohms or less)







4. Check the wiring harness between joint connector (CAN4) A-14 (terminal 7) and ECM connector B-10 (terminal 90) [TC-SST]

OK: Continuity exists (2 ohms or less)







5. Check the wiring harness between joint connector (CAN4) A-14 (terminal 20) and ECM connector B-10 (terminal 91) [TC-SST]

OK: Continuity exists (2 ohms or less)

Q: Is the wiring harness between joint connector (CAN3) C-127 [M/T] or joint connector (CAN4) A-14 [TC-SST] and ECM connector B-10 in good condition?

YES : Check the power supply circuit of the ECM. Refer to MFI Diagnosis.

NO : Repair the wiring harness between joint connector (CAN3) C-127 [M/T] or joint connector (CAN4) A-14 [TC-SST] and ECM connector B-10.