Diagnosis Item 14: Diagnose when the M.U.T.-III cannot receive the data sent by BMU.

caution

When servicing a CAN bus line, earth 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 M.U.T.-III cannot receive the sent data from the BMU" when the M.U.T.-III checks the periodically sent data from each ECU.

TROUBLE JUDGEMENT CONDITIONS

M.U.T.-III judges the trouble when the periodically sent data from BMU cannot be received.

PROBABLE CAUSES

Damaged harness wires and connectors
Power supply circuit malfunction of the BMU
Malfunction of the BMU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-103 joint connector (CAN2) and C-107 BMU connector

caution

The strand end of the twist wire should be within 10 cm 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.

Q. Is the check result normal?

Go to Step 2

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

STEP 2. Resistance measurement at C-103 joint connector (CAN2) and C-107 BMU 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 the joint connector (CAN2) and the BMU connector, and measure at the wiring harness side.

(2)Turn the electric motor 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 auxiliary battery terminal is disconnected.

(4)Continuity between C-103 joint connector (CAN2) terminal No.9 and C-107 BMU connector terminal No.6
OK: Continuity (2 Ω or less)

(5)Continuity between C-103 joint connector (CAN2) terminal No.20 and C-107 BMU connector terminal No.7
OK: Continuity (2 Ω or less)

caution

Strictly observe the specified wiring harness repair procedure. For details refer to

Q. Is the check result normal?

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

<Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN2) and the BMU connector.

STEP 3. Resistance measurement at C-107 BMU connector.

caution

A digital multimeter should be used. For details refer to

(1)Remove the BMU, and measure at the equipment side.

(2)Resistance between C-107 BMU connector terminal Nos.6 and 7
OK: 1 kΩ or more

Q. Is the check result normal?

<1 kΩ or more> Power supply to the BMU may be suspected. Diagnose the BMU. Refer to

<Less than 1 kΩ > Replace the BMU.

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