Inspection Procedure 1: Communication between M.U.T.-III and SRS-ECU cannot be established.

OPERATION

TROUBLE JUDGEMENT

PROBABLE CAUSES

Damaged wiring harness and connectors
Malfunction of SRS-ECU

DIAGNOSIS PROCEDURE

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

Q. Can the M.U.T.-III communicate with the other systems?

	Go to Step 2.

	Check the communication lines for short to earth and open circuit.

STEP 2. Resistance measurement at B-112 SRS-ECU conenctor and B-20 diagnosis connector

(1)Check that the negative auxiliary battery termina is disconnected. If connected, disconnect the negative auxiliary battery termina.

(2)Disconnect B-112 SRS-ECU connector.

(3)

caution

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

Take the following measurements at B-112 SRS-ECU connector and B-16 diagnosis conenctor.

Continuity between B-112 SRS-ECU connector terminal No. 38 and B-20 diagnosis conenctor terminal No. 7.

OK: Continuity (Less than 2 Ω)

Q. Is the check result normal?

	Go to Step 3

	Repair the wiring harness between B-112 SRS-ECU connector terminal No. 38 and B-20 diagnosis connector terminal No. 7.

STEP 3. Resistance measurement at B-112 SRS-ECU connector

(1)Check that the negative auxiliary battery terminal is disconnected. If the negative auxiliary battery terminal is connected, disconnect it.

(2)Disconnect the B-112 SRS-ECU connector.

(3)

caution

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

Take the measurements below at the B-112 harness side connector.

Continuity between terminal No. 41 and body earth

OK: Continuity (less than 2 Ω)

note

Before the wiring harness check, check B-11 <LHD> and B-25 earth connector, and repair if necessary.

Q. Is the check result normal?

	Go to Step 4

	Repair the harness wires between the B-112 SRS-ECU connector terminal No.41 and earth.

STEP 4. Voltage measurement at the B-112 SRS-ECU connector.

(1)Check that the negative auxiliary battery terminal is disconnected. If the negative auxiliary battery terminal is connected, disconnect it.

(2)Disconnect the B-112 SRS-ECU connector.

(3)Connect the negative auxiliary battery terminal.

(4)Electric motor switch to the "ON" position.

(5)

caution

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

Take the measurements below at the B-112 harness side connector.

Voltage between terminal No. 37/43 and body earth

OK: 9 V or more

(6)Disconnect the negative auxiliary battery terminal.

Q. Is the check result normal?

	Go to Step 5

	Repair the wiring harness between B-112 SRS-ECU connector terminal No. 37/43 and the electric motor switch.

STEP 5. Check of the troubles

Q. Is the communication between M.U.T.-III and SRS-ECU possible?

	An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

	Replace SRS-ECU (Refer to ).