Inspection Procedure 2

INSPECTION PROCEDURE 2: Outside/Inside Air Changeover is not possible.

Outside/Inside Air Selection Motor Circuit:

FUNCTION
Changeover between inside air recirculation mode and fresh air mode

PROBABLE CAUSES
- Malfunction of connector.
- Malfunction of the harness (outside/inside air selection damper control motor circuit is open/shorted to ground)
- Malfunction of the outside/inside air selection damper control motor.
- Malfunction of the A/C-ECU.

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, read the 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 to the data link connector.
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 check result satisfactory?

YES : Refer to Diagnostic Trouble Code Chart. General Electrical System Check

NO : Go to Step 2.

STEP 2. Using scan tool MB991958, check actuator test.

1. Connect scan tool MB991958 to the data link connector.
2. Start the engine.
3. Use scan tool MB991958 to run the actuator test.
- Item 72: In/out changeover damper: Fresh
- Item 73: In/out changeover damper: Recirc
- Check that the outside/inside air selection damper control motor operates.

4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Does the motor operate normally?

YES : Go to Step 3.

NO : Go to Step 4.

STEP 3. Recheck for diagnostic trouble code.

Recheck if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to "OFF" position.
3. Turn the ignition switch to "ON" position.
4. Drive the vehicle and check if the diagnostic trouble code is set.

Q: Is the check result satisfactory?

YES : It can be assumed that this malfunction is intermittent.

NO : Replace the heater control.

STEP 4. Check outside/inside air selection damper control motor connector C-108 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q: Is outside/inside air selection damper control motor connector C-108 in good condition?

YES : Go to Step 5.

NO : Repair or replace the connector.

STEP 5. Check the outside/inside air selection damper control motor.







CAUTION: Cut off the battery voltage when the damper is in the inside/outside air position.

Check the outside/inside air selection damper control motor by the following procedures.







Q: Does the outside/inside air selection damper control motor work normally?

YES : Go to Step 6.

NO : Replace the outside/inside air selection damper control motor.


STEP 6. Check A/C-ECU connector C-19 and junction block connector C-215 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q: Are A/C-ECU connector C-19 and junction block connector C-215 in good condition?

YES : Go to Step 7.

NO : Repair or replace the connector.

STEP 7. Check the wiring harness for open circuit.







1. Disconnect A/C-ECU connector C-19 and outside/inside air selection damper control motor connector C-108, and measure the resistance at the wiring harness side.







2. Measure the resistance between A/C-ECU connector C-19 terminal 28 and outside/inside air selection damper control motor connector C-108 terminal 4.

OK: Less than 2 ohms

Q: Is the check result normal?

YES : Go to Step 9.

NO : Go to Step 8.

STEP 8. Check the wiring harness between A/C-ECU connector C-19 (terminal 28) and outside/inside air selection damper control motor connector C-108 (terminal 4).







Q: Is the wiring harness between A/C-ECU connector C-19 (terminal 28) and outside/inside air selection damper control motor connector C-108 (terminal 4) in good condition?

YES : It can be assumed that this malfunction is intermittent.

NO : Repair the wiring harness.

STEP 9. Check the wiring harness for open circuit.







1. Disconnect A/C-ECU connector C-19 and outside/inside air selection damper control motor connector C-108, and measure the resistance at the wiring harness side.







2. Measure the resistance between A/C-ECU connector C-19 terminal 29 and outside/inside air selection damper control motor connector C-108 terminal 5.

OK: Less than 2 ohms

Q: Is the check result normal?

YES : Go to Step 11.

NO : Go to Step 10.

STEP 10. Check the wiring harness between A/C-ECU connector C-19 (terminal 29) and outside/inside air selection damper control motor connector C-108 (terminal 5).






Q: Is the wiring harness between A/C-ECU connector C-19 (terminal 29) and outside/inside air selection damper control motor connector C-108 (terminal 5) in good condition?

YES : It can be assumed that this malfunction is intermittent.

NO : Repair the wiring harness.

STEP 11. Check the wiring harness for open circuit.







1. Disconnect junction block connector C-215 and outside/inside air selection damper control motor connector C-108, and measure the resistance at the wiring harness side.







2. Measure the resistance between junction block connector C-215 terminal 16 and outside/inside air selection damper control motor connector C-108 terminal 1.

OK: Less than 2 ohms

Q: Is the check result normal?

YES : Go to Step 13.

NO : Go to Step 12.

STEP 12. Check the wiring harness between junction block connector C-215 (terminal 16) and outside/inside air selection damper control motor connector C-108 (terminal 1).







Q: Is the wiring harness between junction block connector C-215 (terminal 16) and outside/inside air selection damper control motor connector C-108 (terminal 1) in good condition?

YES : It can be assumed that this malfunction is intermittent.

NO : Repair the wiring harness.

STEP 13. Measure the resistance at A/C-ECU connector C-19.







1. Disconnect A/C-ECU connector C-19, and measure the resistance at the wiring harness side.







2. Measure the resistance value between terminal 28 and ground.

OK: 1.5 kohms or more

Q: Does the measured resistance value correspond with this range?

YES : Go to Step 15.

NO : Go to Step 14.

STEP 14. Check the wiring harness between A/C-ECU connector C-19 (terminal 28) and outside/inside air selection damper control motor connector C-108 (terminal 4).







Q: Is the wiring harness between A/C-ECU connector C-19 (terminal 28) and outside/inside air selection damper control motor connector C-108 (terminal 4) in good condition?

YES : It can be assumed that this malfunction is intermittent.

NO : Repair the wiring harness.

STEP 15. Measure the resistance at A/C-ECU connector C-19.







1. Disconnect A/C-ECU connector C-19, and measure the resistance at the wiring harness side.







2. Measure the resistance value between terminal 29 and ground.

OK: 1.5 kohms or more

Q: Does the measured resistance value correspond with this range?

YES : Go to Step 17.

NO : Go to Step 16.

STEP 16. Check the wiring harness between A/C-ECU connector C-19 (terminal 29) and outside/inside air selection damper control motor connector C-108 (terminal 5).







Q: Is the wiring harness between A/C-ECU connector C-19 (terminal 29) and outside/inside air selection damper control motor connector C-108 (terminal 5) in good condition?

YES : It can be assumed that this malfunction is intermittent.

NO : Repair the wiring harness.

STEP 17. Retest the system.

Check the trouble symptom again.

Q: Is the check result satisfactory?

YES : It can be assumed that this malfunction is intermittent.

NO : Replace the heater control.