Inspection Procedure 8: The A/C-ECU cannot communicate with M.U.T.-III..

COMMENTS ON TROUBLE SYMPTOM

If communication with all other systems is not possible, there is a high possibility that there is a malfunction of the diagnosis line. If only the air conditioner cannot communicate, malfunction of the A/C-ECU and diagnosis line is suspected.

PROBABLE CAUSES

Damaged harness wires and connectors
Malfunction of the A/C-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the communication with other systems.

Q. Can the M.U.T.-III communicate with SRS-ECU?

	Go to Step 2.

	Check and repair the M.U.T.-III diagnosis line.

STEP 2. Connector check: B-16 A/C-ECU connector, B-16 diagnosis connector

Q. Is the check result normal?

	Go to Step 3 <LHD>.

	Go to Step 4 <RHD>.

	Repair the connector.

STEP 3. Check the wiring harness between B-16 A/C-ECU connector terminal No. 7, 22 and B-20 diagnosis connector terminal No. 7, 4, 5.

note

Before checking the wiring harness, check the joint connectors B-04, B-05, B-06, and earth connector B-11, and repair them if necessary.

Check the earth for open circuit.

Q. Is the check result normal?

	Intermittent malfunction. (GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to handle Intermittent Malfunction)

	Repair the wiring harness.

STEP 4. Check the wiring harness between B-16 A/C-ECU connector terminal No. 7, 22 and B-20 diagnosis connector terminal No. 7, 4.

note

Before checking the wiring harness, check the joint connectors B-05 and earth connector B-11, and repair them if necessary.

Check the earth for open circuit.

Q. Is the check result normal?

	Intermittent malfunction. (GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to handle Intermittent Malfunction)

	Repair the wiring harness.

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