Inspection Procedure 19: The temperature of rear air conditioner cannot be controlled <Vehicles with dual automatic A/C>

COMMENTS ON TROUBLE SYMPTOM
If the temperature of rear air conditioner con not be controlled, the rear heater controller circuit system or the rear air mix damper control motor circuit system may be defective.

PROBABLE CAUSES

  • Malfunction of rear air mix damper control motor
  • Malfunction of rear heater controller
  • Malfunction of the A/C-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code
Check whether the air conditioner sets a diagnosis code or not.

Q. Is the check result normal?
Go to Step 2.
Refer to diagnosis code chart .

STEP 2. M.U.T.-III actuator test
Carry out the actuator test. (Refer to .)

  • Item 13: R.Air mix dumper motor: 0%
  • Item 14: R.Air mix dumper motor: 50%
  • Item 15: R.Air mix dumper motor: 100%

Q. Does the rear blower motor work normally?
Go to Step 3.
Go to Step 8.

STEP 3. M.U.T.-III data list
Check that the following service data display contents are normal. (Refer to .)

  • Item 12: R.Air mix potentiometer
  • Item 13: R.Air mix potentiometer (Target)
  • Item 51: Rear Temperature setting

Q. Is the check result normal?
Go to Step 8.
Go to Step 4.

STEP 4. Connector check: E-03 rear heater controller connector




Q. Is the check result normal?

Go to Step 5.

Repair the connector.

STEP 5. Check the rear heater controller
Refer to .

Q. Is the check result normal?
Go to Step 6.
Replace the rear heater controller.

STEP 6. Connector check: C-106 A/C-ECU



Q. Is the check result normal?

Go to Step 7.

Repair the connector.

STEP 7. Check the wiring harness between E-03 rear heater controller connector (terminals 14, 15, and 16) and C-106 A/C-ECU connector (terminals 15, 14 and 1).







note Prior to the wiring harness inspection, check intermediate connector C-128, and repair if necessary.

  • Check the input line for open circuit.

Q. Is the check result normal?

Go to Step 8.

Repair the wiring harness.

STEP 8. Recheck the trouble symptom

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
Replace the A/C-ECU.