INSPECTION PROCEDURE 2: Power Supply Circuit System

OPERATION

The SRS-ECU is energized by the ignition switch (IG1) through multi-purpose fuse 2 and the SRS-ECU terminal 24 and multi-purpose fuse 3 and the SRS-ECU terminal 23.
If the power supply to the SRS-ECU has failed, M.U.T.-III will not be able to communicate with it.

PROBABLE CAUSES

Damaged wiring harness or connector
Defective battery
Charging system failed
Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Resistance measurement at SRS-ECU connector D-24.

(1)Disconnect the negative battery terminal.

(2)Disconnect the connector D-24.

(3)

caution

Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.

Check for continuity between D-24 harness side connector terminals 40 and body earth.
OK: Continuity (Less than 2 Ω)

Q. Is the check results normal?

	Then go to Step 2.

	Repair the wiring harness between SRS-ECU connector D-24 terminals 40 and the body earth. Then go to Step 3.

STEP 2. Check the harness wires for short circuit to earth between SRS-ECU connector D-24 (terminal No.23 and 24) and ignition switch connector D-309 (terminal No.2).

note

After inspecting intermediate connectors D-403 and D-405 inspect the wiring harness. If intermediate connectors D-403 and D-405 are damaged, repair or replace them. Then go to Step 3

Q. Are the harness wires between SRS-ECU connector D-24 (terminal No.23 and 24) and ignition switch connector D-309 (terminal No.2) in good condition?

	Go to Step 3.

	Replace the harness wires between SRS-ECU connector D-24 and ignition switch connector D-309. Then go to Step 3.

STEP 3. Retest the system.

Q. Can the SRS-ECU communicate with the M.U.T.-III?

	It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Cope with Intermittent Malfunction .

	Replace the SRS-ECU (Refer to ).