Inspection Procedure 11

*This document updated per manufacturer TSB #08-55-003


INSPECTION PROCEDURE 11: When Sunlight Intensity Changes, Air Outlet Temperature Does Not Change. [up to December 2007]

Photo Sensor Circuit:

CIRCUIT OPERATION
When the blower air temperature cannot be changed even if the preset temperature is changed, the sensors may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the photo sensor
- Malfunction of the A/C-ECU
- Malfunction of connector.
- Malfunction of the harness.

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. Check the defogger and outside/inside air selection damper control motor operation.

Q: Do the defogger and outside/inside air selection damper control motor work normally?

YES : Go to Step 2.

NO : Refer to Heater and A/C, Symptom chart. Symptom Chart

STEP 2. 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 : Go to Step 3.

NO : Automatic A/C Diagnostic Trouble Code Descriptions

STEP 3. Using scan tool MB991958, check data list.

1. Connect scan tool MB991958 to the data link connector.
2. Start the engine.
3. Set scan tool MB991958 to the data reading mode.
- Item 67: Photo sensor

4. Cover the photo sensor and security indicator with your hand or a shop towel.

NOTE: Check that the voltage displayed on the scan tool changes.

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

Q: Does the voltage displayed on the scan tool change when the photo sensor and security indicator is covered?

YES : Replace the A/C-ECU. Check that the A/C works normally.

NO : Go to Step 4.

STEP 4. Check A/C-ECU connector C-20 and photo sensor connector C-101 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are A/C-ECU connector C-20 and photo sensor connector C-101 in good condition?

YES : Go to Step 5.

NO : Repair or replace the connector. Refer to general (electrical), Harness Connector Inspection.

STEP 5. Check the wiring harness between photo sensor connector C-101 (terminals 4 and 1) and A/C-ECU connector C-20 (terminals 19 and 18).

Q: Is the wiring harness between photo sensor connector C-101 (terminals 4 and 1) and A/C-ECU connector C-20 (terminals 19 and 18) in good condition?

YES : Go to Step 6.

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

STEP 6. Replace the photo sensor.

Q: Does the A/C operate normally?

YES : No action is necessary and testing is complete.

NO : Replace the A/C-ECU. Check that the A/C works normally.