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Test 1A: Identifying ATC System Problems

WARNING: This page is about a different car, the 1998 Dodge Intrepid and 1998 Chrysler Concorde. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). See Fig 1 . Using scan tool and the most current diagnostic program cartridge, ensure there is communication with Body Control Module (BCM) and Powertrain Control Module (PCM). If scan tool has a blank screen, go to next step. If any other communication problem exists, go to ACCESSORIES & EQUIPMENT, BODY CONTROL COMPUTER TESTS - LH BODY article. If there are no communication problems, go to step 7).
  2. Turn ignition off. Disconnect scan tool from DLC. Check connector for an open, loose, or disconnected terminal. Repair as necessary.
  3. Using an external ohmmeter, ensure that there is continuity between ground and DLC terminals No. 4 (Black wire) and No. 5 (Black/Light Green wire). If continuity is present, go to next step. If continuity is not present, repair wire(s) as necessary.
  4. Using an external voltmeter, check voltage at DLC terminal No. 16 (Pink wire). If battery voltage is not present, go to next step. If battery voltage is present, go to step 6).
  5. If battery voltage is not present, check fuse No. 19 (10-amp) located in junction block, behind end cover at left side of instrument panel. See Figure and Figure . Replace fuse if blown. If fuse blows again, repair DLC battery feed circuit as necessary.
  6. Substitute scan tool cable with a known-good cable. If scan tool screen is no longer blank and scan tool is functioning properly, go to next step. If scan tool screen is still blank, replace defective scan tool. If there are no communication problems, go to next step.
  7. Using scan tool select ENGINE and then READ DTCS. If scan tool does not display any PCM DTCs, go to next step. See appropriate ENGINE PERFORMANCE article if any of the following A/C-heater system related PCM DTCs are displayed:
    • ECT SENSOR VOLTAGE TOO LOW
    • ECT SENSOR VOLTAGE TOO HIGH
    • A/C PRESSURE SENSOR VOLTAGE TOO HIGH
    • A/C PRESSURE SENSOR VOLTAGE TOO LOW
    • LOW SPEED FAN CONTROL RELAY CIRCUIT
    • HIGH SPEED FAN CONTROL RELAY CIRCUIT
    • A/C CLUTCH RELAY CIRCUIT
    • ENGINE IS COLD TOO LONG
  8. Using scan tool, select BODY SYSTEM, BODY COMPUTER, SENSORS and then IGNITION VOLTAGE. Turn ignition on. If battery voltage is displayed, go to next step. If battery voltage is not displayed, go to ACCESSORIES & EQUIPMENT, BODY CONTROL COMPUTER TESTS - LH BODY article.
  9. Using scan tool, select BODY SYSTEM, BODY COMPUTER, and then READ DTCS. If ATC system related BCM DTCs are not present, go to next step. If ATC system related BCM DTCs are present, go to TEST 1B: IDENTIFYING ATC SYSTEM BCM DIAGNOSTIC TROUBLE CODES  .
  10. Using scan tool, select BODY SYSTEM, and then AUTO TEMP CTRL. If scan tool does not display NO RESPONSE, go to next step. If scan tool displays NO RESPONSE, see appropriate ACCESSORIES & EQUIPMENT - BODY CONTROL COMPUTER - VEHICLE COMMUNICATIONS article.
  11. If no BCM DTCs exist and any ATC control head switch is inoperative, go to TEST 2A: INOPERATIVE ATC CONTROL HEAD SWITCH  . If no BCM DTCs exist and recirculation door is inoperative, go to TEST 12A: RECIRCULATION DOOR ACTUATOR STALL TEST FAILURE  .
  12. If no BCM DTCs exist and there is a problem with A/C clutch operation, go to TEST 14A: COMPRESSOR CLUTCH CIRCUIT  . If no BCM DTCs exist and temperature control/blend air door is inoperative, go to TEST 15A: INOPERATIVE TEMPERATURE/BLEND AIR DOOR  .
  13. If no BCM DTCs exist and blower motor is inoperative, go to TEST 16A: INOPERATIVE BLOWER MOTOR  . If no BCM DTCs exist and blower motor speed(s) are incorrect, go to TEST 17A: INCORRECT BLOWER MOTOR SPEEDS  .
  14. If no BCM DTCs exist and there is a problem with A/C control head illumination, but instrument panel lights operate properly, go to TEST 18A: ATC CONTROL HEAD ILLUMINATION  . If no BCM DTCs exist and mode door is inoperative, go to TEST 19A: INOPERATIVE MODE DOOR  . If no BCM DTCs exist and temperature control is incorrect in sun or shade, go to TEST 21A: INCORRECT TEMPERATURE CONTROL IN SUN OR SHADE  .
  15. If instrument panel lights do not operate properly, see appropriate ACCESSORIES & EQUIPMENT - ILLUMINATION/INTERIOR LIGHTS article. If rear window defogger is inoperative, see appropriate ACCESSORIES & EQUIPMENT - REAR WINDOW DEFOGGER article.
Fig 1: Locating Data Link Connector (DLC)
G98A04003Courtesy of CHRYSLER CORP.
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