INSPECTION PROCEDURE 2: Power supply circuit system


OPERATION




PROBABLE CAUSES



  • Damaged wiring harness and connectors
  • Battery failure
  • Malfunction of the charging system
  • Malfunction of SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Fuse Nos. 2 check.

Q. Is the fuse in good condition?
Go to Step 3.
Go to Step 2

STEP 2. Fuse open circuit check
(1)Replace the fuse.
(2)Turn the ignition switch to the "ON" position, wait for at least one minute, and then turn the switch OFF.
(3)Check the fuse.

Q. Is the fuse in good condition?
Go to Step 3.
Repair the wiring harness IG1A line between the ETACS-ECU connector and the SRS-ECU connector, and replace the fuse.

STEP 3. Resistance measurement at the SRS-ECU connector.

(1)While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the SRS-ECU connector.
(2)Take the measurements below at the SRS-ECU wiring harness side connectors.

  • Continuity GND2 line between SRS-ECU wiring harness side connector and body earth
OK: Continuity (less than 2 Ω)

Q. Is the check result normal?

Go to Step 4.

Repair the wiring harness GND2 line between the SRS-ECU connector and the earth.

STEP 4. Voltage measurement at the SRS-ECU connector.
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.

(2)While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the SRS-ECU connector.
(3)Connect the negative battery terminal.
(4)Ignition switch: ON
(5)Take the measurements below at the SRS-ECU harness side connector.

  • Voltage between IG1A line and body earth
OK: 9 V or more
(6)Disconnect the negative battery terminal.

Q. Is the check result normal?

Go to Step 6.

Go to Step 5.

STEP 5. Resistance measurement at the SRS-ECU connector.
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
(2)Disconnect the ETACS-ECU connector.

(3)While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the SRS-ECU connector.
(4)
  • Continuity IG1A line between ETACS-ECU connector and SRS-ECU connector
OK: Continuity (less than 2 Ω)

Q. Is the check result normal?

Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).

Repair the wiring harness IG1A line between the ETACS-ECU connector and the SRS-ECU connector.

STEP 6. Trouble symptom check.

Q. Is the communication between M.U.T.-III and SRS-ECU possible?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace SRS-ECU (Refer to ).