Code No.B1086, B1087: Motor output system for air outside/inside air circulation switching damper

COMMENTS ON TROUBLE SYMPTOM
If this code is set, there is an open circuit (B1087) or short circuit (B1086) in the wiring harness between the inside/outside air selection damper control motor and the A/C-ECU.

PROBABLE CAUSE

  • Malfunction of the inside/outside air selection damper control motor
  • Damaged wiring harness or connectors
  • Malfunction of the semi automatic air conditioner control panel (A/C-ECU)

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III actuator test
Carry out the actuator test.

  • Item 37, 38: inside/outside air selection damper control motor

Q. Does the blower motor work normally?
Replace the semi automatic air conditioner control panel (A/C-ECU).
Go to Step 2.

STEP 2. Connector check: B-11 inside/outside air selection damper control motor connector


Q. Is the check result normal?

Go to Step 3.

Repair the connector.

STEP 3. Voltage measurement at B-11 inside/outside air selection damper control motor connector.


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the "ON" position.

(3)Measure the voltage between terminal 1 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

STEP 4. Check the wiring harness between B-11 inside/outside air selection damper control motor connector terminal No.1 and the ignition switch (IG2).




note Prior to the wiring harness inspection, check junction block connector B-230, and repair if necessary.

  • Check the blower relay power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 5. Check the inside/outside air selection damper control motor.
Refer to GROUP 55A, Blower motor, resistor and outside/inside air selection damper control motor .

Q. Is the inside/outside air selection damper control motor in good condition?
Go to Step 6.
Replace the inside/outside air selection damper control motor.

STEP 6. Connector check: B-113 A/C-ECU connector


Q. Is the check result normal?

Go to Step 7.

Repair the connector.

STEP 7. Check the wiring harness between B-113 A/C-ECU connector (terminals 17 and 9) and B-11 inside/outside air selection damper control motor connector (terminals 4 and 5).





  • Check the inside/outside air selection damper control motor earth line for open or short circuit.

Q. Is the check result normal?

Go to Step 8.

Repair the wiring harness.

STEP 8. Check whether the diagnosis code is reset.

Q. Is the diagnosis code set?
Replace the semi automatic air conditioner control panel (A/C-ECU).
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).