Automatic Air Conditioning: Diagnosis Mitsubishi Galant IX

DIAGNOSTIC TROUBLE CODE CHART

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DIAGNOSTIC TROUBLE CODE (DTC) LIST

DIAGNOSTIC TROUBLE CODE PROCEDURES

Note. For test procedures not included in this article, refer to DIAGNOSTIC TROUBLE CODE CHART < LOW TYPE> or DIAGNOSTIC TROUBLE CODE CHART < MIDDLE TYPE> .

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DTC SET CONDITION

1. DTC B1001 is set if there is a short circuit in the interior temperature sensor input circuit.
2. DTC B1002 is set if there is a defective connector connection, or if there is an open circuit in the harness.

Current trouble

1. The A/C-ECU, the interior air temperature sensor, or connector(s) or wiring between the two may be defective.

Past trouble

1. If DTC B1001 or B1002 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the A/C-ECU and the interior air temperature sensor. If the connectors and wiring are normal, and obviously the ECU is the cause of the trouble, replace the ECU. If in doubt, do not replace the ECU.

TROUBLESHOOTING HINT

1. Malfunction of connector.
2. Malfunction of the harness.
3. Malfunction of the interior temperature sensor.
4. Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tool

1. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: Vehicle Communication Interface (V.C.I.) MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A (Vehicles with CAN communication system)

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1. STEP 1. Using scan tool MB991958, diagnose the CAN bus line. Use scan tool MB991958 to diagnose the CAN bus lines. Connect scan tool MB991958 to the data link connector. Turn the ignition switch to "ON" position. Diagnose the CAN bus line. Q: Is the check result satisfactory? YES: Go to Step 2. NO: Repair the CAN bus lines. (Refer to «CAN COMMUNICATION SIGNAL TABLE»(ref-205491-S12473639462005111900000) ). Then go to Step 7 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "ON" position. Check if the DTC is set. Q: Is the check result satisfactory? YES: It can be assumed that this malfunction is intermittent. Refer to «HOW TO USE TROUBLESHOOTING/INSPECTION SERVICE»(ref-215473-S08378565702006011200000) . NO: Go to Step 3.
3. STEP 3. Using scan tool MB991958, check data list item 01: interior temperature sensor. 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. Connect scan tool MB991958 to the data link connector. Start the engine. Set scan tool MB991958 to the data reading mode for item 01: Interior temperature sensor. Check that the interior temperature matches the displayed value on the scan tool. NOTE: When this DTC is set and the system is in fail-safe status, the value of service data displays 25°C. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the interior temperature match the displayed value on the scan tool? YES: Replace the A/C-ECU. Then go to Step 7 . NO: Go to Step 4.
4. STEP 4. Check A/C-ECU connector C-15, C-16 and interior temperature sensor connector C-123 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connectors C-15, C-16 and interior temperature sensor connector C-123 in good condition? YES: Go to Step 5. NO: Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-215474-S16579441322006011200000) . . Then go to Step 7 .
5. STEP 5. Check the wiring harness between A/C-ECU connector C-15 (terminals 20), C-16 (terminals 22) and interior temperature sensor connector C-123 (terminals 1 and 2). NOTE: Also check joint connector C-03 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-03 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-215474-S16579441322006011200000) . Q: Are the wiring harnesses between A/C-ECU connector C-15 (terminals 20), C-16 (terminals 22) and interior temperature sensor connector C-123 (terminals 1 and 2) in good condition? YES: Go to Step 6. NO: Repair the wiring harness. Then go to Step 7 .
6. STEP 6. Check the interior temperature sensor. Disconnect interior temperature sensor connector C-123. When the resistance between the sensor terminals is measured under two or more temperature conditions, the resistance should approximately satisfy the illustrated values. NOTE: The temperature conditions when checking should not exceed the range shown in the diagram. Q: Is the interior temperature sensor in good condition? YES: Replace the A/C-ECU. Then go to Step 7. NO: Replace the interior temperature sensor. Then go to Step 7.
7. STEP 7. Recheck for diagnostic trouble code. Check again if the DTC is set. Connect scan tool MB991958 to the data link connector Turn the ignition switch to the "ON" position. Check if the DTC is set. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES: The procedure is complete. NO: Return to Step 1 .

SYMPTOM CHART

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SYMPTOM PROCEDURES

Note. For test procedures for inspection procedures 1 through 10, refer to SYMPTOM PROCEDURES < LOW TYPE > or SYMPTOM PROCEDURES < MIDDLE TYPE > . For test procedure for inspection procedure 11, refer to RADIATOR FAN MOTOR CHECK .

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TROUBLESHOOTING HINTS

1. Improper amount of refrigerant
2. Malfunction of the A/C pressure sensor
3. Malfunction of the photo sensor
4. Malfunction of the A/C-ECU
5. The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector