Code No.B1088, B1089: Motor sensor system for air mix damper

COMMENTS ON TROUBLE SYMPTOM

This code is set when the air mixing damper control motor potentiometer does not send any signal to the A/C-ECU due to short or open circuit.

PROBABLE CAUSE

Malfunction of the front air mixing damper control motor and potentiometer
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 data list

Check that the following service data display contents are normal (Refer to

).

Item 22: Air mixing damper potentiometer
Item 32: Air mixing potentiometer (Target)

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 2.

STEP 2. Connector check: B-113 A/C-ECU connector and B-12 air mixing damper control motor and potentiometer connector

Q. Is the check result normal?

Go to Step 3.

Repair the connector.

STEP 3. Check the wiring harness between B-113 A/C-ECU connector (terminals 13, 15 and 12) and B-12 air mixing damper control motor and potentiometer connector (terminals 4, 3 and 5) <LHD> or (terminals 5,3 and 4) <RHD>.

Check the potentiometer power supply, earth and signal line for open and short circuit.

Q. Is the check result normal?

Go to Step 4.

Repair the wiring harness.

STEP 4. Check the air mixing damper control motor and potentiometer.

Refer to

.

Q. Is the check result normal?

	Go to Step 5.

	Replace the front air mixing damper control motor and potentiometer.

STEP 5. 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 ).