DIAGNOSTIC ITEM 16: Diagnose When The Scan Tool (M.U.T.-IIISE) Cannot Receive The Data Sent By ASC-ECU: Diagnosis

Required Special Tools:

MB991223: Harness Set
MB992006: Extra Fine Probe

STEP 1. Connector check: joint connector (CAN3) and ASC-ECU connector
CAUTION: The strand end of the twist wire should be within 10 cm (3.9 inches) from the connector. For details refer to TEST EQUIPMENT .

When checking the joint connector, ensure that its wiring harness side and its short pins are not damaged.

Q: Is the check result normal?

YES: Go to Step 2.

NO: Repair the defective connector. Replace the joint connector as necessary.
STEP 2. Resistance measurement at joint connector (CAN3) and ASC-ECU connector.
CAUTION: A digital multimeter should be used. For details refer to TEST EQUIPMENT .

CAUTION: The test wiring harness should be used. For details refer to TEST EQUIPMENT .
1. Disconnect joint connector (CAN3) and the ASC-ECU connector, and measure at the wiring harness side.
2. Turn the ignition switch to the "LOCK" (OFF) position.
  CAUTION: When measuring the resistance, disconnect the negative battery terminal. For details refer to TEST EQUIPMENT .
3. Ensure that the negative battery terminal is disconnected.
4. Continuity between joint connector (CAN3) terminal No. 8 and ASC-ECU connector terminal No. 11
  OK: The resistance should be 2 ohms or less
5. Continuity between joint connector (CAN3) terminal No. 19 and ASC-ECU connector terminal No. 10
  OK: The resistance should be 2 ohms or less
Q: Is the check result normal?

YES: <All the resistances measure 2 ohms or less> Go to Step 3.

NO: <Either or all of the resistances measure more than 2 ohms> Repair the wiring harness between joint connector (CAN3) and the ASC-ECU connector.
STEP 3. Resistance measurement at ASC-ECU connector.
CAUTION: A digital multimeter should be used. For details refer to TEST EQUIPMENT .
1. Remove the ASC-ECU, and measure at the equipment side.
2. Resistance between ASC-ECU connector terminal Nos.11 and 10
  OK: 1 kΩ or more
Q: Is the check result normal?

YES: Power supply to the ASC-ECU may be suspected. Diagnose the ASC system. Refer to TROUBLE SYMPTOM CHART .

NO: Replace the hydraulic unit (ASC-ECU).