54C-DIAGNOSTICS ITEM 8

Diagnostic Item 8: Diagnose when the scan tool (M.U.T.-IIISE) cannot receive the data sent by gateway-ECU (for BSW). <Vehicles with Blind Spot Warning [BSW] (with Lane Change Assist) system>

caution

When servicing a CAN bus line, ground yourself by touching a metal object such as an unpainted water pipe. If you fail to do, a component connected to the CAN bus line may be broken.

FUNCTION

The diagnostic result demonstrates that "the scan tool (M.U.T.-IIISE) cannot receive the sent data from the gateway-ECU (for BSW)" when the scan tool (M.U.T.-IIISE) checks the periodically sent data from each ECU and cannot receive the gateway-ECU (for BSW) data only.

TROUBLE JUDGMENT CONDITIONS

The scan tool (M.U.T.-IIISE) judges the trouble when the periodically sent data from gateway-ECU (for BSW) cannot be received.

TROUBLESHOOTING HINTS

Damaged harness wires and connectors
Power supply circuit malfunction of the gateway-ECU (for BSW)
Malfunction of the gateway-ECU (for BSW)

DIAGNOSIS

Required Special Tools:

MB991223: Harness Set
MB992006: Extra Fine Probe

STEP 1. Connector check: joint connector (CAN1) and gateway-ECU (for BSW) connector

caution

The strand end of the twist wire should be within 10 cm (3.9 inches) from the connector. For details refer to

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

Is the check result normal?

Go to Step 2

Repair the defective connector. Replace the joint connector as necessary.

STEP 2. Resistance measurement at joint connector (CAN1) and gateway-ECU (for BSW) connector.

caution

A digital multimeter should be used. For details refer to

caution

The test wiring harness should be used. For details refer to

(1) Disconnect joint connector (CAN1) and the gateway-ECU (for BSW) connector, and measure at the wiring harness side.

(2) Turn the ignition switch to the "LOCK" (OFF) position.

(3)

caution

When measuring the resistance, disconnect the negative auxiliary battery terminal. For details refer to

Ensure that the negative battery terminal is disconnected.

(4) Continuity between joint connector (CAN1) terminal No.5 and gateway-ECU (for BSW) connector terminal No.3

OK: The resistance should be 2 ohms or less

(5) Continuity between joint connector (CAN1) terminal No.16 and gateway-ECU (for BSW) connector terminal No.2

OK: The resistance should be 2 ohms or less

Is the check result normal?

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

: <Either or all of the resistances measure more than 2 ohms> Repair the wiring harness between joint connector (CAN1) and the gateway-ECU (for BSW) connector.

STEP 3. Resistance measurement at gateway-ECU (for BSW) connector.

caution

A digital multimeter should be used. For details refer to

(1) Remove the gateway-ECU (for BSW), and measure at the equipment side.

(2) Resistance between gateway-ECU (for BSW) connector terminal Nos.3 and 2

OK: 1 kΩ or more

Is the check result normal?

Power supply to the gateway-ECU (for BSW) may be suspected. Diagnose the gateway-ECU (for BSW). Refer to

Replace the gateway-ECU (for BSW).