Inspection Procedure 6: Communication with the SWS Monitor is not Possible.












caution Whenever the ECU is replaced, ensure that the power supply circuit, the earthing circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM
The SWS monitor may be connected improperly.

PROBABLE CAUSES

  • Malfunction of the SWS monitor body (I/F cartridge)
  • Malfunction of the SWS monitor harness
  • Malfunction of the ETACS-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check that the M.U.T.-III communicates with the other systems.
Check whether the M.U.T.-III can communicate with the other systems.

Q. Is the check result normal?
Go to Step 2.
Diagnose the system, which cannot communicate with the M.U.T.-III.

STEP 2. Check that the M.U.T.-III can communicate with the system.
When the ignition switch is turned ON, check if the M.U.T.-III can communicate with the system.

Q. Is the check result normal?
Refer to Inspection Procedure 2 "Communication with the ETACS-ECU is not possible ."
Go to Step 3.

STEP 3. Connector check: D-420 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 4.
Repair the defective connector.

STEP 4. Resistance measurement at the D-420 ETACS-ECU connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Resistance between D-420 ETACS-ECU connector terminal No.56 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 6.
Go to Step 5.

STEP 5. Check the wiring harness between D-420 ETACS-ECU connector terminal No.56 and body earth.

  • Check the earth wires for open circuit.

Q. Are the check results normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use troubleshooting/Inspection Service Points ).
Repair the wiring harness.

STEP 6. Connector check: D-127 diagnosis connector

Q. Is the check result normal?
Go to Step 7.
Repair the defective connector.

STEP 7. Check the wiring harness from D-420 ETACS-ECU connector terminal Nos.51, 59 and 67 to D-127 diagnosis connector terminal Nos.9, 3 and 1.
note Prior to the wiring harness inspection, check joint connector D-34, and repair if necessary.

  • Check the communication lines for open circuit.

Q. Are the check results normal?
Replace the ETACS-ECU.
Repair the wiring harness.