Diagnosis Item 15: Diagnose when the M.U.T.-III cannot receive the data sent by A/C-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

If the M.U.T.-III can not communicate with the A/C-ECU, this diagnosis result will be set.

TRUBLE JUDGEMENT CONDITIONS

If a communication flag is not set for the A/C-ECU, the ETACS-ECU determines that there is a failure.

TROUBLESHOOTING HINTS

Malfunction of the connector [joint connector (CAN1) or A/C-ECU connector improperly connected]
Malfunction of the wiring harness [open circuit between the A/C-ECU connector and the joint connector (CAN1), or power supply circuit to the A/C-ECU]
Malfunction of the A/C-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-105 joint connector (CAN1) and C-111 A/C-ECU connector

caution

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

Q. Is the check result normal?

	Go to Step 2.

	Repair the defective connector.

STEP 2. Check the wiring harness between C-111 A/C-ECU connector and C-105 joint connector (CAN1)

caution

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

Disconnect A/C-ECU connector and joint connector (CAN1), and check the following wiring harness.

The wiring harness between C-111 A/C-ECU connector terminal No.11 and C-105 joint connector (CAN1) terminal No.9 <CAN_H>
The wiring harness between C-111 A/C-ECU connector terminal No.12 and C-105 joint connector (CAN1) terminal No.22 <CAN_L>

Q. Is the check result normal?

	Check the power supply circuit of the A/C-ECU. Refer to Group 55 - Troubleshooting .

	Repair the wiring harness.