Inspection Procedure 6

INSPECTION PROCEDURE 6: Outside/Inside Air Changeover Is Not Possible.

Outside/Inside Damper Control Motor Circuit:

CIRCUIT OPERATION
If the outside/inside air selection damper control motor does not operate normally, the outside/inside air selection damper control motor system may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the outside/inside air selection damper control motor
- Malfunction of the A/C-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check for diagnostic trouble code.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Check if an A/C-ECU DTC is set.







1. Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Refer to DIAGNOSTIC TROUBLE CODE CHART. Diagnostic Trouble Code Descriptions

NO : Go to Step 2.

STEP 2. Check outside/inside air selection damper control motor connector C-111 and A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are outside/inside air selection damper control motor connector C-111 and A/C-ECU connector C-20 in good condition?

YES : Go to Step 3.

NO : Repair or replace the connector. Check that the A/C works normally.

STEP 3. Check the wiring harness between A/C-ECU connector C-20 (terminal 26, 25, 27, 24 and 29) and outside/inside air selection damper control motor connector C-111 (terminals 2, 5, 4. 1 and 3).

- Check the A/C-ECU signal line for open and short circuit.

Q: Are the wiring harness between A/C-ECU connector C-20 (terminal 26, 25, 27, 24 and 29) and outside/inside air selection damper control motor connector C-111 (terminals 2, 5, 4. 1 and 3) in good condition?

YES : Go to Step 4.

NO : Repair the wiring harness. Check that the A/C works normally.

STEP 4. Replace the outside/inside air selection damper control motor and check the trouble symptom again

Check the trouble symptom again.

Q: Is the check result satisfactory?

YES : The procedure is complete.

NO : Replace the A/C-ECU.