Inspection Procedure 12: When Sunlight Intensity Changes, Air Outlet Temperature Does Not Change: 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

1. 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 MANUAL A/C DIAGNOSIS .

2. STEP 2. Using scan tool MB991958, read 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.
   1. Check if an A/C-ECU DTC is set.
   2. Connect scan tool MB991958 to the data link connector.
   3. Turn the ignition switch to the "ON" position.
   4. Check if the DTC is set.
   5. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   YES:  Refer to DIAGNOSTIC TROUBLE CODE CHART  .

   NO:  Go to Step 3.

   Fig 1: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Using scan tool MB991958, check data list item 06: Photo sensor. 
   1. Connect scan tool MB991958 to the data link connector.
   2. Start the engine.
   3. Set scan tool MB991958 to the data reading mode for item 06: Photo sensor.
      • Check that the display on the scan tool changes when the photo sensor is covered with hands.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the sensor within the specified range? 

   YES:  Go to  Step 7.

   NO:  Go to Step 4.

   Fig 2: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check A/C-ECU connectors C-15, C-16 and photo sensor connector C-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Are A/C-ECU connectors C-15, C-16 and photo sensor connector C-04 in good condition? 

   YES:  Go to Step 5.

   NO:  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION . Check that the A/C works normally.

   Fig 3: Identifying Connector Terminals C-04

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   Fig 4: Identifying Connector C-15, C-16 Terminals

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. Check the wiring harness between photo sensor connector C-04 (terminal 1, 2) and A/C-ECU connector C-15 (terminal 19), C-16 (terminal 25). 

   Q: Is the wiring harness between photo sensor connector C-04 (terminal 1, 2) and A/C-ECU connector C-15 (terminal 19), C-16 (terminal 25) in good condition? 

   YES:  Go to Step 6.

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

   Fig 5: Identifying Connector Terminals C-04

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   Fig 6: Identifying Connector C-15, C-16 Terminals

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
6. 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.

7. STEP 7. Check the refrigerant level. 

   Use the refrigerant recovery station to remove all of the refrigerant, and then calculate the amount of the refrigerant and charge it.

   Q: Is the refrigerant level correct? 

   YES:  Refer to SYMPTOM CHART .

   NO:  Correct the refrigerant level (Refer to ON-VEHICLE SERVICE ). Check that the A/C works normally.