Diagnosis Item 16: Diagnose when the M.U.T.-III cannot receive the data sent by EPS-ECU.



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 EPS-ECU" when the M.U.T.-III checks the periodically sent data from each ECU and cannot receive the EPS-ECU data only.

TROUBLE JUDGEMENT CONDITIONS


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

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Connector check: joint connector (CAN1) and EPS-ECU 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 joint connector (CAN1) and EPS-ECU 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 EPS-ECU connector, and measure at the wiring harness side.
(2)Turn off the power supply mode of the electric motor switch.
(3)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4)Continuity between joint connector (CAN1) terminal No.4 and EPS-ECU connector terminal No.4
OK: Continuity (2 Ω or less)
(5)Continuity between joint connector (CAN1) terminal No.15 and EPS-ECU connector terminal No.3
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

<All the resistances measure 2 Ω or less> Power supply to the EPS-ECU may be suspected. Diagnose the EPS. Refer to GROUP 37 - Troubleshooting .
NO : <Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN1) and the EPS-ECU connector.