INSPECTION PROCEDURE 7: A/C Outlet Air Temperature does not Increase: 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.
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 DTC set?
  - YES: Refer to DIAGNOSTIC TROUBLE CODE CHART .
  - NO: Go to Step 2.
    
    Fig 1: Connecting Special Tool To Data Link Connector
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 2. Check air mixing damper control motor connector C-118 and A/C-ECU connector C-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are air mixing damper control motor connector C-118 and A/C-ECU connector C-19 in good condition?
- YES: Go to Step 3.
- NO: Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION . Check that the A/C works normally.
STEP 3. Check the wiring harness between A/C-ECU connector C-19 (terminals 29, 35, 36, 34 and 28) and air mixing damper control motor connector C-118 (terminals 3, 2, 5, 4 and 1).
- Check the A/C-ECU signal line for open and short circuit.
  Q: Are the wiring harness between A/C-ECU connector C-19 (terminals 29, 35, 36, 34 and 28) and air mixing damper control motor connector C-118 (terminals 3, 2, 5, 4 and 1) in good condition?
  - YES: Go to Step 4.
  - NO: Repair the wiring harness. Check that the A/C works normally.
STEP 4. Replace the air mixing 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.