Automatic Air Conditioning: Diagnosis Mitsubishi Eclipse IV рестайлинг

AUTOMATIC A/C TROUBLESHOOTING STRATEGY

Use these steps to plan your diagnostic strategy. If you follow them carefully, you will be sure that you have exhausted most of the possible ways to find a heater, air conditioning and ventilation fault.

1. Gather information from the customer.
2. Verify that the condition described by the customer exists.
3. Find the malfunction by following the Symptom Chart (Refer to «SYMPTOM CHART»(ref-308267-S06979096182009020200000) ).
4. Verify malfunction is eliminated.

HOW TO CONNECT THE SCAN TOOL (MUT-III)

Required Special Tools

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

Scheme 1

1. Ensure that the ignition switch is at the "LOCK" (OFF) position.
2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824 and the personal computer.
4. Connect special tool MB991910 to special tool MB991824
5. Connect special tool MB991910 to the data link connector.
6. Turn the power switch of special tool MB991824 to the "ON" position. NOTE: When the special tool MB991824 is energized, the special tool MB991824 indicator light will be illuminated in a green color.
7. Start the MUT-III system on the personal computer. NOTE: Disconnecting the scan tool special tool MB991824 is the reverse of the connecting sequence, making sure that the ignition switch is at the "LOCK" (OFF) position.

HOW TO READ AND ERASE DIAGNOSTIC TROUBLE CODES

Required Special Tools

1. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Note. If the battery voltage is low, diagnostic trouble codes will not be output. Check the battery if scan tool MB991958 does not display.

Scheme 2

1. Connect the scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System Select."
5. Choose "AUTO A/C" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Select "Diagnostic Trouble Code."
8. If a DTC is set, it is shown.
9. Choose "Erase DTC" to erase the DTC.

HOW TO PERFORM ACTUATOR TEST

Required Special Tools

1. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Scheme 3

1. Connect the scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System Select."
5. Choose "AUTO A/C" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Choose "Actuator Test" from "AUTO A/C" screen.
8. Choose an appropriate item and select the "OK" button.

HOW TO DIAGNOSE THE CAN BUS LINE

Required Special Tools

1. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Scheme 4

1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "CAN bus diagnosis" from the start-up screen.
4. When the vehicle information is displayed, confirm that it matches the vehicle whose CAN bus lines will be diagnosed. If they match, go to step 8 . If not, go to step 5.
5. Select "view vehicle information" button.
6. When the vehicle information is displayed, confirm again that it matches the vehicle which is diagnosed CAN bus line. If they match, go to step 8 . If not, go to step 5 .
7. Press the "OK" button.
8. When the options are displayed, choose the options (mark the check) and then select "OK".

DIAGNOSTIC TROUBLE CODE CHART

DIAGNOSTIC TROUBLE CODE CHART

Scheme 5

DIAGNOSIS

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, check data list. 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. 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 (77°F). Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the interior temperature match the displayed value on the scan tool? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check heater air intake duct sensor connector C-105 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is heater air intake duct sensor connector C-105 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the heater air intake duct sensor. Disconnect heater air intake duct sensor connector C-105. 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 heater air intake duct sensor in good condition? YES : Go to Step 5. NO : Replace the heater air intake duct sensor.
5. STEP 5. Check A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connectors C-20 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to, «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Measure the resistance at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 22 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 22) and heater air intake duct sensor connector C-105 (terminal 2). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 22) and heater air intake duct sensor connector C-105 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 14

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, check data list. 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. 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 (77°F). Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the interior temperature match the displayed value on the scan tool? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check heater air intake duct sensor connector C-105 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is heater air intake duct sensor connector C-105 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the heater air intake duct sensor. Disconnect heater air intake duct sensor connector C-105. 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 heater air intake duct sensor in good condition? YES : Go to Step 5. NO : Replace the heater air intake duct sensor.
5. STEP 5. Check A/C-ECU connector C-15 and C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connectors C-15 and C-20 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and heater air intake duct sensor connector C-105, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 22 and heater air intake duct sensor connector C-105 terminal 2. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 22) and heater air intake duct sensor connector C-105 (terminal 2). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 22) and heater air intake duct sensor connector C-105 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and heater air intake duct sensor connector C-105, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 20 and heater air intake duct sensor connector C-105 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-15 (terminal 20) and heater air intake duct sensor connector C-105 (terminal 1). NOTE: Also check joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 20) and heater air intake duct sensor connector C-105 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 27

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, check data list. 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. Item 02: Ambient air temperature sensor Check that the ambient 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 20°C (68°F). Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the interior temperature match the displayed value on the scan tool? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check ambient air temperature sensor connector A-28 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is ambient air temperature sensor connector A-28 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the ambient air temperature sensor. Disconnect ambient air temperature sensor connector A-28. Measure the resistance between the sensor terminals under at least two temperatures. The resistance values should meet the values shown. NOTE: The temperature should be within the shown range. Q: Is the ambient air temperature sensor in good condition? YES : Go to Step 5. NO : Replace the ambient air temperature sensor.
5. STEP 5. Check A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connectors C-20 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Measure the resistance at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 23 and ground. OK: 1kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 23) and heater air intake duct sensor connector A-28 (terminal 2). NOTE: Also check intermediate connector C-21 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-21 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 23) and heater air intake duct sensor connector A-28 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 37

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, check data list. 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. Item 02: Ambient air temperature sensor Check that the ambient 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 20°C (68°F). Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the interior temperature match the displayed value on the scan tool? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check ambient air temperature sensor connector A-28 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is ambient air temperature sensor connector A-28 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the ambient air temperature sensor. Disconnect ambient air temperature sensor connector A-28. 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 ambient air temperature sensor in good condition? YES : Go to Step 5. NO : Replace the ambient air temperature sensor.
5. STEP 5. Check A/C-ECU connector C-15 and C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connectors C-15 and C-20 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and ambient air temperature sensor connector A-28, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 23 and ambient air temperature sensor connector A-28 terminal 2. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 23) and ambient air temperature sensor connector A-28 (terminal 2). NOTE: Also check intermediate connector C-21 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-21 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 23) and ambient air temperature sensor connector A-28 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and ambient air temperature sensor connector A-28, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 20 and ambient air temperature sensor connector A-28 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-15 (terminal 20) and ambient air temperature sensor connector A-28 (terminal 1). NOTE: Also check intermediate connector C-21 and joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-21 and joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 20) and ambient air temperature sensor connector A-28 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 54

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, check data list. 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. Item 20: air thermo sensor Check that the temperature behind the evaporator 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 -6°C (28°F). Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the sensor within the specified range? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check air thermo sensor connector C-102 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is air thermo sensor connector C-102 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the air thermo sensor. Disconnect the air thermo sensor connector C-102. Measure the resistance between connector terminals 1 and 2 under at least two different temperatures. The resistance values should generally match those in the graph. NOTE: The temperature at the check should not exceed the range in the graph. Q: Is the air thermo sensor in good condition? YES : Go to Step 5. NO : Replace the air thermo sensor.
5. STEP 5. Check A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connectors C-20 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Measure the resistance at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 24 and ground. OK: 1kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 24) and air thermo sensor connector C-102 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 24) and air thermo sensor connector C-102 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 64

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, check data list. 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. Item 20: air thermo sensor Check that the temperature behind the evaporator 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 -6°C (28°F). Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the sensor within the specified range? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check air thermo sensor connector C-102 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is air thermo sensor connector C-102 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the air thermo sensor. Disconnect the air thermo sensor connector C-102. Measure the resistance between connector terminals 1 and 2 under at least two different temperatures. The resistance values should generally match those in the graph. NOTE: The temperature at the check should not exceed the range in the graph. Q: Is the air thermo sensor in good condition? YES : Go to Step 5. NO : Replace the air thermo sensor.
5. STEP 5. Check A/C-ECU connector C-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connector C-15 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and air thermo sensor connector C-102, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 24 and air thermo sensor connector C-102 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 24) and air thermo sensor connector C-102 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 24) and air thermo sensor connector C-102 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and air thermo sensor connector C-102, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 20 and air thermo sensor connector C-102 terminal 2. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-15 (terminal 20) and air thermo sensor connector C-102 (terminal 2). NOTE: Also check joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 20) and air thermo sensor connector C-102 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 80

Required Special Tool

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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Scheme 92

1. STEP 1. Using scan tool MB991958, check data list. 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. Item 63: Air mix potentiometer Item 64: Air mix potentiometer (Target) NOTE: Check that the set position of the heater control matches the displayed position on the scan tool. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the sensor within the specified range? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check air mixing damper control motor and potentiometer connector C-109 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is air mixing damper control motor and potentiometer connector C-109 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the air mixing damper control motor and potentiometer. CAUTION: Do not apply battery voltage when the damper is in the MAX COOL or MAX HOT position. Operate the air mixing damper control motor as described in the table below. AIR MIXING DAMPER CONTROL MOTOR OPERATION REFERENCE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the MAX COOL position Connect terminal 2 to the positive battery terminal Connect terminal 1 to the negative battery terminal The lever moves from the MAX COOL position to the MAX HOT position At the MAX HOT position Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal The lever moves from the MAX HOT position to the MAX COOL position Measure the resistances between connector terminals 3 and 5, and between 3 and 7, while the air mixing damper control motor is running. The resistances should change gradually within the standard value. Standard value: 1.7 (MAX HOT) - 5.0 (MAX COOL) kohms Q: Are the air mixing damper control motor and potentiometer in good condition? YES : Go to Step 5. NO : Replace the air mixing damper control motor and potentiometer.
5. STEP 5. Check A/C-ECU connector C-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connector C-15 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and air mixing damper control motor and potentiometer connector C-109, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 20 and air mixing damper control motor and potentiometer connector C-109 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-15 (terminal 20) and air mixing damper control motor and potentiometer connector C-109 (terminal 7). NOTE: Also check joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 20) and air mixing damper control motor and potentiometer connector C-109 (terminal 7) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Check A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connector C-20 in good condition? YES : Go to Step 9. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
9. STEP 9. Measure the voltage at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the voltage at the wiring harness side. Turn the ignition switch to the "ON" position. Turn the temperature control dial to the MAX HOT position. Measure the voltage between terminal 29 and ground. OK: 1.3-1.5 volts Q: Is the check result normal? YES : Go to Step 11 . NO : Go to Step 10.
10. STEP 10. Check the wiring harness between A/C-ECU connector C-20 (terminal 29) and air mixing damper control motor and potentiometer connector C-109 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 29) and air mixing damper control motor and potentiometer connector C-109 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
11. STEP 11. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 93

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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Scheme 106

1. STEP 1. Using scan tool MB991958, check data list. 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. Item 63 : Air mix potentiometer Item 64 : Air mix potentiometer (Target) NOTE: Check that the set position of the heater control matches the displayed position on the scan tool. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the sensor within the specified range? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check air mixing damper control motor and potentiometer connector C-109 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is air mixing damper control motor and potentiometer connector C-109 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the air mixing damper control motor and potentiometer. CAUTION: Do not apply battery voltage when the damper is in the MAX COOL or MAX HOT position. Operate the air mixing damper control motor as described in the table below. AIR MIXING DAMPER CONTROL MOTOR OPERATION REFERENCE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the MAX COOL position Connect terminal 2 to the positive battery terminal Connect terminal 1 to the negative battery terminal The lever moves from the MAX COOL position to the MAX HOT position At the MAX HOT position Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal The lever moves from the MAX HOT position to the MAX COOL position Measure the resistances between connector terminals 3 and 5, and between 3 and 7, while the air mixing damper control motor is running. The resistances should change gradually within the standard value. Standard value: 1.7 (MAX HOT) - 5.0 (MAX COOL) kohms Q: Are the air mixing damper control motor and potentiometer in good condition? YES : Go to Step 5. NO : Replace the air mixing damper control motor and potentiometer.
5. STEP 5. Check A/C-ECU connector C-15 and C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connectors C-15 and C-20 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and air mixing damper control motor and potentiometer connector C-109, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 16 and air mixing damper control motor and potentiometer connector C-109 terminal 5. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-15 (terminal 16) and air mixing damper control motor and potentiometer connector C-109 (terminal 5). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 16) and air mixing damper control motor and potentiometer connector C-109 (terminal 5) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and air mixing damper control motor and potentiometer connector C-109, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 29 and air mixing damper control motor and potentiometer connector C-109 terminal 3. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-20 (terminal 29) and air mixing damper control motor and potentiometer connector C-109 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 29) and air mixing damper control motor and potentiometer connector C-109 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Measure the resistance at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance between terminal 29 and ground. OK: 1kohms or more Q: Is the check result satisfactory? YES : Go to Step 12 . NO : Go to Step 11.
11. STEP 11. Check the wiring harness between A/C-ECU connector C-20 (terminal 29) and air mixing damper control motor and potentiometer connector C-109 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 29) and air mixing damper control motor and potentiometer connector C-109 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
12. STEP 12. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check that the diagnostic trouble code is not set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 107

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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Scheme 145

1. STEP 1. 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. 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 only diagnostic trouble code B1045 set? YES < Only B1045 is set > : Go to Step 11 . NO < B1041 is set simultaneously > : Refer to «DTC B1041: AIR MIXING DAMPER CONTROL MOTOR AND POTENTIOMETER (POTENTIOMETER SYSTEM SHORTED TO ITS POWER SUPPLY)»(ref-308267-S24000621312009020200000) . NO < B1042 is set simultaneously > : Refer to «DTC B1042: AIR MIXING DAMPER CONTROL MOTOR AND POTENTIOMETER (POTENTIOMETER SYSTEM SHORTED TO ITS GROUND)»(ref-308267-S10078647802009020200000) . NO < B1065 is set simultaneously > : Go to Step 2.
2. STEP 2. Check air mixing damper control motor and potentiometer connector C-109 and A/C pressure sensor connector A-34 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are air mixing damper control motor and potentiometer connector C-109 and A/C pressure sensor connector A-34 in good condition? YES : Go to Step 3. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
3. STEP 3. Check the A/C pressure sensor operation. Assemble a gauge manifold on the high pressure service valve. Disconnect the A/C pressure sensor connector and connect special tool test harness MB991658 as shown in the illustration. Turn ON the engine and then turn ON the air conditioner switch. At this time, check to see that the voltage of A/C pressure sensor terminal No. 2 reflects the specifications of the figure. NOTE: The allowance shall be defined as +/-5%. Q: Is the A/C pressure sensor operating properly? YES : Go to Step 4. NO : Replace the A/C pressure sensor.
4. STEP 4. Check the air mixing damper control motor and potentiometer. CAUTION: Do not apply battery voltage when the damper is in the MAX COOL or MAX HOT position. Operate the air mixing damper control motor as described in the table below. AIR MIXING DAMPER CONTROL MOTOR OPERATION REFERENCE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the MAX COOL position Connect terminal 2 to the positive battery terminal Connect terminal 1 to the negative battery terminal The lever moves from the MAX COOL position to the MAX HOT position At the MAX HOT position Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal The lever moves from the MAX HOT position to the MAX COOL position Measure the resistances between connector terminals 3 and 5, and between 3 and 7, while the air mixing damper control motor is running. The resistances should change gradually within the standard value. Standard value: 1.7 (MAX HOT) - 5.0 (MAX COOL) kohms Q: Are the air mixing damper control motor and potentiometer in good condition? YES : Go to Step 5. NO : Replace the air mixing damper control motor and potentiometer.
5. STEP 5. Check A/C-ECU connector C-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connector C-15 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 12 and ground. OK: 1.5 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-15 (terminal 12) and A/C pressure sensor connector A-34 (terminal 3). NOTE: Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 12) and A/C pressure sensor connector A-34 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 16 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-15 (terminal 16) and air mixing damper control motor and potentiometer connector C-109 (terminal 5). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 16) and air mixing damper control motor and potentiometer connector C-109 (terminal 5) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
11. STEP 11. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 42: air mix damper motor 0% (MAX COOL position) Item 43: air mix damper motor 100% (MAX HOT position) Item 44: air mix damper motor 50% (middle position) Check that the air mixing damper control motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 13 . NO : Go to Step 12.
12. STEP 12. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
13. STEP 13. Check air mixing damper control motor and potentiometer connector C-109 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is air mixing damper control motor and potentiometer connector C-109 in good condition? YES : Go to Step 14. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
14. STEP 14. Check the air mixing damper control motor and potentiometer. CAUTION: Do not apply battery voltage when the damper is in the MAX COOL or MAX HOT position. Operate the air mixing damper control motor as described in the table below. AIR MIXING DAMPER CONTROL MOTOR OPERATION REFERENCE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the MAX COOL position Connect terminal 2 to the positive battery terminal Connect terminal 1 to the negative battery terminal The lever moves from the MAX COOL position to the MAX HOT position At the MAX HOT position Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal The lever moves from the MAX HOT position to the MAX COOL position Measure the resistances between connector terminals 3 and 5, and between 3 and 7, while the air mixing damper control motor is running. The resistances should change gradually within the standard value. Standard value: 1.7 (MAX HOT) - 5.0 (MAX COOL) kohms Q: Are the air mixing damper control motor and potentiometer in good condition? YES : Go to Step 15. NO : Replace the air mixing damper control motor and potentiometer.
15. STEP 15. Check A/C-ECU connector C-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connectors C-15 in good condition? YES : Go to Step 16. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
16. STEP 16. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and air mixing damper control motor and potentiometer connector C-109, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 20 and air mixing damper control motor and potentiometer connector C-109 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 18 . NO : Go to Step 17.
17. STEP 17. Check the wiring harness between A/C-ECU connector C-15 (terminal 1) and air mixing damper control motor and potentiometer connector C-109 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 1) and air mixing damper control motor and potentiometer connector C-109 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
18. STEP 18. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and air mixing damper control motor and potentiometer connector C-109, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 2 and air mixing damper control motor and potentiometer connector C-109 terminal 2. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 20 . NO : Go to Step 19.
19. STEP 19. Check the wiring harness between A/C-ECU connector C-15 (terminal 2) and air mixing damper control motor and potentiometer connector C-109 (terminal 2). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 2) and air mixing damper control motor and potentiometer connector C-109 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
20. STEP 20. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 1 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 22 . NO : Go to Step 21.
21. STEP 21. Check the wiring harness between A/C-ECU connector C-15 (terminal 1) and air mixing damper control motor and potentiometer connector C-109 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 1) and air mixing damper control motor and potentiometer connector C-109 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
22. STEP 22. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 2 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 24 . NO : Go to Step 23.
23. STEP 23. Check the wiring harness between A/C-ECU connector C-15 (terminal 2) and air mixing damper control motor and potentiometer connector C-109 (terminal 2). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 2) and air mixing damper control motor and potentiometer connector C-109 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
24. STEP 24. Check junction block connector C-215 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is junction block connectors C-215 in good condition? YES : Go to Step 25. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
25. STEP 25. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and junction block connector C-215, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 28 and junction block connector C-215 terminal 16. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 27 . NO : Go to Step 26.
26. STEP 26. Check the wiring harness between A/C-ECU connector C-20 (terminal 28) and junction block connector C-215 (terminal 16). NOTE: Also check joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 28) and junction block connector C-215 (terminal 16) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
27. STEP 27. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 146

Required Special Tool

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Scheme 147

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Scheme 156

Scheme 157

Scheme 158

Scheme 159

1. STEP 1. Using scan tool MB991958, check data list. 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. Item 55: Air outlet c/o potentiometer Item 56: Air outlet c/o potentiometer (Target) NOTE: Check that the set position of the heater control matches the displayed position on the scan tool. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the sensor within the specified range? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 20 and mode selection damper control motor and potentiometer connector C-104 terminal 7. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 6 . NO : Go to Step 5.
5. STEP 5. Check the wiring harness between A/C-ECU connector C-15 (terminal 20) and mode selection damper control motor and potentiometer connector C-104 (terminal 7). NOTE: Also check joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 20) and mode selection damper control motor and potentiometer connector C-104 (terminal 7) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
6. STEP 6. Measure the voltage at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the voltage at the wiring harness side. Turn the ignition switch to the "ON" position. Move the mode selection damper control motor to the DEF position. Measure the voltage between terminal 21 and ground. OK: 0.4-0.8 volt Q: Is the check result satisfactory? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Check the mode selection damper control motor. CAUTION: Do not apply battery voltage when the damper is in the FACE or DEF position. Check the mode selection damper control motor by the following procedures. MODE SELECTION DAMPER CONTROL MOTOR CHECKING PROCEDURE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the FACE position Connect terminal 2 to the positive battery terminal Connect terminal 1 to the negative battery terminal The lever moves from the FACE position to the DEF position At the DEF position Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal The lever moves from the DEF position to the FACE position Q: Is the mode selection damper control motor in good condition? YES : Go to Step 9. NO : Replace the mode selection damper control motor and potentiometer.
9. STEP 9. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 160

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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Scheme 175

Scheme 176

Scheme 177

Scheme 178

1. STEP 1. Using scan tool MB991958, check data list. 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. Item 55: Air outlet c/o potentiometer Item 56: Air outlet c/o potentiometer (Target) NOTE: Check that the set position of the heater control matches the displayed position on the scan tool. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the sensor within the specified range? YES : Go to Step 2. NO : Go to Step 3 .
2. STEP 2. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
3. STEP 3. Check A/C-ECU connector C-15, C-20 and mode selection damper control motor and potentiometer connector C-104 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connector C-15, C-20 and mode selection damper control motor and potentiometer connector C-104 in good condition? YES : Go to Step 4. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
4. STEP 4. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 16 and mode selection damper control motor and potentiometer connector C-104 terminal 5. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 6 . NO : Go to Step 5.
5. STEP 5. Check the wiring harness between A/C-ECU connector C-15 (terminal 16) and mode selection damper control motor and potentiometer connector C-104 (terminal 5). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 16) and mode selection damper control motor and potentiometer connector C-104 (terminal 5) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
6. STEP 6. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and mode selection damper control motor and potentiometer connector C-104, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 21 and mode selection damper control motor and potentiometer connector C-104 terminal 3. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
8. STEP 8. Measure the resistance at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Turn the ignition switch to the "ON" position. Move the mode selection damper control motor to the DEF position. Measure the resistance between terminal 21 and ground. OK: 1 kohms or more Q: Is the check result satisfactory? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 21) and mode selection damper control motor and potentiometer connector C-104 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Check the mode selection damper control motor. CAUTION: Do not apply battery voltage when the damper is in the FACE or DEF position. Check the mode selection damper control motor by the following procedures. MODE SELECTION DAMPER CONTROL MOTOR CHECKING PROCEDURE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the FACE position Connect terminal 2 to the positive battery terminal Connect terminal 1 to the negative battery terminal The lever moves from the FACE position to the DEF position At the DEF position Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal The lever moves from the DEF position to the FACE position Q: Is the mode selection damper control motor in good condition? YES : Go to Step 11. NO : Replace the mode selection damper control motor and potentiometer.
11. STEP 11. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 179

Required Special Tool

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Scheme 180

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Scheme 199

Scheme 200

Scheme 201

1. STEP 1. 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. 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 diagnostic trouble code B1045 set? YES : Refer to «DTC B1045: AIR MIXING DAMPER CONTROL MOTOR AND POTENTIOMETER (ACTIVATING SYSTEM FAILURE)»(ref-308267-S19300554832009020200000) . NO : Go to Step 2.
2. STEP 2. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 67: air outlet c/o damper (Bi_Level position) Item 68: air mix damper motor (DEF position) Item 69: air mix damper motor (DEF/FOOT position) Item 70: air mix damper motor (FACE position) Item 71: air mix damper motor (FOOT position) Check that the mode selection damper control motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 4 . NO : Go to Step 3.
3. STEP 3. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
4. STEP 4. Check A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104 in good condition? YES : Go to Step 5. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
5. STEP 5. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 4 and mode selection damper control motor and potentiometer connector C-104 terminal 2. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 7 . NO : Go to Step 6.
6. STEP 6. Check the wiring harness between A/C-ECU connector C-15 (terminal 4) and mode selection damper control motor and potentiometer connector C-104 (terminal 1). Q: Is the wiring harnesses between A/C-ECU connector C-15 (terminal 4) and mode selection damper control motor and potentiometer connector C-104 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
7. STEP 7. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and mode selection damper control motor and potentiometer connector C-104, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 11 and mode selection damper control motor and potentiometer connector C-104 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 9 . NO : Go to Step 8.
8. STEP 8. Check the wiring harness between A/C-ECU connector C-15 (terminal 11) and mode selection damper control motor and potentiometer connector C-104 (terminal 1). Q: Is the wiring harnesses between A/C-ECU connector C-15 (terminal 11) and mode selection damper control motor and potentiometer connector C-104 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
9. STEP 9. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 4 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 11 . NO : Go to Step 10.
10. STEP 10. Check the wiring harness between A/C-ECU connector C-15 (terminal 4) and mode selection damper control motor and potentiometer connector C-104 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 4) and mode selection damper control motor and potentiometer connector C-104 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
11. STEP 11. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 11 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 13 . NO : Go to Step 12.
12. STEP 12. Check the wiring harness between A/C-ECU connector C-15 (terminal 11) and mode selection damper control motor and potentiometer connector C-104 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 11) and mode selection damper control motor and potentiometer connector C-104 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
13. STEP 13. Check the mode selection damper control motor. CAUTION: Do not apply battery voltage when the damper is in the FACE or DEF position. Check the mode selection damper control motor by the following procedures. MODE SELECTION DAMPER CONTROL MOTOR CHECKING PROCEDURE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the FACE position Connect terminal 2 to the positive battery terminal Connect terminal 1 to the negative battery terminal The lever moves from the FACE position to the DEF position At the DEF position Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal The lever moves from the DEF position to the FACE position Q: Is the mode selection damper control motor in good condition? YES : Go to Step 14. NO : Replace the mode selection damper control motor and potentiometer.
14. STEP 14. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

TROUBLE JUDGMENT

If the A/C-ECU ceases communicating once (i.e. bus off) and then returns to it, the A/C-ECU will not communicate for three minutes immediately after that point. This three-minute period is called "Penalty mode." Immediately after the A/C-ECU returns to communication, the DTC is set.

Required Special Tools

1. MB991223: Harness Set
2. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: USB Cable MB991910: Main Harness A

Scheme 202

1. STEP 1. Using scan tool MB991958, diagnose the CAN bus line. 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. Turn the ignition switch to the "ON" position. Diagnose the CAN bus line. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the CAN bus line found to be normal? YES : Go to Step 2. NO : Repair the CAN bus lines. Refer to «CONTROLLER AREA NETWORK (CAN)»(ref-313851) .
2. STEP 2. 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 : There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) ). NO : Go to Step 3.
3. STEP 3. Replace the A/C-ECU and then recheck the DTC. 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 : Go to Step 1 .

The A/C-ECU receives engine control system-related signals from the ECM < M/T > or PCM < A/T > via CAN bus lines. If the A/C-ECU cannot receive the necessary signals, DTC U1100 will be set.

Required Special Tools

1. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Scheme 203

1. STEP 1. Using scan tool MB991958, diagnose the CAN bus line. 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. Turn the ignition switch to the "ON" position. Diagnose the CAN bus line. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the CAN bus line found to be normal? YES : Go to Step 2. NO : Repair the CAN bus lines. Refer to «CONTROLLER AREA NETWORK (CAN)»(ref-313851) .
2. STEP 2. Using scan tool MB991958 read the ECM < M/T > or PCM < A/T > diagnostic trouble code. Check whether an engine and automatic transaxle DTCs are set or not. Turn the ignition switch to the "ON" position. Check for engine and automatic transaxle DTCs. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES : Go to Step 3. NO : Diagnose the ECM < M/T > or PCM < A/T > (Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308262-S12174514092009020200000) < 3.8L ENGINE >).
3. STEP 3. Using scan tool MB991958, check for any diagnostic trouble code. Check if a DTC, which relates to CAN communication-linked systems below, is set. Combination meter DTC indicating a time-out error related to the engine or automatic transaxle control system ABS-ECU DTC indicating a time-out error related to the engine or automatic transaxle control system Turn the ignition switch to the "ON" position. Check for a DTC related to the relevant system. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES : Go to Step 5 . NO : Go to Step 4.
4. STEP 4. Using scan tool MB991958 read the ECM < M/T > or PCM < A/T > diagnostic trouble code. Check whether an engine and automatic transaxle DTCs are set or not. Turn the ignition switch to the "ON" position. Check for engine and automatic transaxle DTCs. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES : The procedure is complete. NO : Replace the A/C-ECU.
5. STEP 5. Replace the A/C-ECU and then recheck the DTC. 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 : Go to Step 1 .

The A/C-ECU receives the vehicle speed signal and the coolant temperature from the ECM < M/T > or PCM < A/T > via CAN bus lines. If failure information is sent to the vehicle speed signal and the coolant temperature, DTC U1120 will be set.

TROUBLESHOOTING HINTS

1. Malfunction of connector.
2. Malfunction of the harness (CAN line is open/shorted to ground)
3. Malfunction of the A/C-ECU.
4. Malfunction of the ECM < M/T > or PCM < A/T >.

Required Special Tools

1. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Scheme 204

1. STEP 1. Using scan tool MB991958, diagnose the CAN bus line. 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. Turn the ignition switch to the "ON" position. Diagnose the CAN bus line. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the CAN bus line found to be normal? YES : Go to Step 2. NO : Repair the CAN bus lines. Refer to «CONTROLLER AREA NETWORK (CAN)»(ref-313851) .
2. STEP 2. Using scan tool MB991958, read the ECM < M/T > or PCM < A/T > diagnostic trouble code. Check whether any engine or automatic transaxle DTCs are set or not. Turn the ignition switch to the "ON" position. Check for engine and automatic transaxle DTCs. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES : Go to Step 3. NO : Refer to - Diagnostic Trouble Code «DIAGNOSTIC TROUBLE CODE CHART»(ref-308262-S12174514092009020200000) < 3.8L ENGINE >.
3. STEP 3. Using scan tool MB991958, check for any diagnostic trouble code. Check if a DTC, which relates to CAN communication-linked systems below, is set. Combination meter DTC indicating a time-out error related to the engine or automatic transaxle control system ETACS DTC indicating a time-out error related to the engine or automatic transaxle control system Turn the ignition switch to the "ON" position. Check for a DTC related to the relevant system. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES : Go to Step 5 . NO : Go to Step 4.
4. STEP 4. Replace the ECM < M/T > or PCM < A/T > and then recheck the DTC. Check again if the DTC is set. 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 : Replace the A/C-ECU.
5. STEP 5. Replace the A/C-ECU and then recheck the DTC. 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 : Go to Step 1 .

SYMPTOM CHART

SYMPTOMS REFERENCE

Scheme 205

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe

Scheme 206

Scheme 207

Scheme 208

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1. STEP 1. Check A/C-ECU connector C-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connector C-15 in good condition? YES : Go to Step 2. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
2. STEP 2. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and the battery harness, and measure at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 3 and battery. OK: Less than 10 ohms Q: Is the check result normal? YES : Go to Step 4 . NO : Go to Step 3.
3. STEP 3. Check the wiring harness between A/C-ECU connector C-15 (terminal 3) and the battery. NOTE: Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 3) and the battery in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
4. STEP 4. Check A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connector C-20 in good condition? YES : Go to Step 5. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
5. STEP 5. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 36 and ignition switch connector. OK: Less than 10 ohms Q: Is the check result normal? YES : Go to Step 7 . NO : Go to Step 6.
6. STEP 6. Check the wiring harness between A/C-ECU connector C-20 (terminal 28) and the ignition switch (IG2). NOTE: Also check intermediate connector C-24 and joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 and joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 28) and the ignition switch (IG2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
7. STEP 7. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 27 and ground. OK: Less than 10 ohms Q: Is the check result normal? YES : Go to Step 9 . NO : Go to Step 8.
8. STEP 8. Check the wiring harness between A/C-ECU connector C-20 (terminal 27) and ground. Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 27) and ground in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
9. STEP 9. Retest the system Check that the A/C works normally. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 219

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. 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. 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 : Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308267-S33679661832009020200000) . NO : Go to Step 2.
2. STEP 2. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 72: In/out changeover damper: Fresh Item 73: In/out changeover damper: Recirc Check that the outside/inside air selection damper control motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 3. NO : Go to Step 4 .
3. STEP 3. Recheck for diagnostic trouble code. Recheck if the DTC is set. Erase the DTC. Turn the ignition switch to "OFF" position. Turn the ignition switch to "ON" position. Drive the vehicle and check if the diagnostic trouble code is set. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
4. STEP 4. Check outside/inside air selection damper control motor connector C-108 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is outside/inside air selection damper control motor connector C-108 in good condition? YES : Go to Step 5. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
5. STEP 5. Check the outside/inside air selection damper control motor. CAUTION: Cut off the battery voltage when the damper is in the inside/outside air position. Check the outside/inside air selection damper control motor by the following procedures. OUTSIDE/INSIDE AIR SELECTION DAMPER CONTROL MOTOR CHECKING PROCEDURE LEVER POSITION BATTERY CONNECTION LEVER OPERATION At the outside position Connect terminal 1 to the positive battery terminal Connect terminal 5 to the negative battery terminal The lever moves from the outside position to the inside position At the inside position Connect terminal 1 to the positive battery terminal Connect terminal 4 to the negative battery terminal The lever moves from the inside position to the outside position Q: Does outside/inside air selection damper control motor work normally? YES : Go to Step 6. NO : Replace the outside/inside air selection damper control motor.
6. STEP 6. Check A/C-ECU connector C-15 and junction block connector C-215 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connector C-15 and junction block connector C-215 in good condition? YES : Go to Step 7. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
7. STEP 7. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and outside/inside air selection damper control motor connector C-108, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 5 and outside/inside air selection damper control motor connector C-108 terminal 4. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 9 . NO : Go to Step 8.
8. STEP 8. Check the wiring harness between A/C-ECU connector C-15 (terminal 5) and outside/inside air selection damper control motor connector C-108 (terminal 4). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 5) and outside/inside air selection damper control motor connector C-108 (terminal 4) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
9. STEP 9. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and outside/inside air selection damper control motor connector C-108, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 6 and outside/inside air selection damper control motor connector C-108 terminal 5. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 11 . NO : Go to Step 10.
10. STEP 10. Check the wiring harness between A/C-ECU connector C-15 (terminal 6) and outside/inside air selection damper control motor connector C-108 (terminal 5). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 6) and outside/inside air selection damper control motor connector C-108 (terminal 5) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
11. STEP 11. Check the wiring harness for open circuit. Disconnect junction block connector C-215 and outside/inside air selection damper control motor connector C-108, and measure the resistance at the wiring harness side. Measure the resistance between junction block connector C-215 terminal 16 and outside/inside air selection damper control motor connector C-108 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 13 . NO : Go to Step 12.
12. STEP 12. Check the wiring harness between junction block connector C-215 (terminal 16) and outside/inside air selection damper control motor connector C-108 (terminal 1). NOTE: Also check joint connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-01 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between junction block connector C-215 (terminal 16) and outside/inside air selection damper control motor connector C-108 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
13. STEP 13. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 5 and ground. OK: 1.5 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 15 . NO : Go to Step 14.
14. STEP 14. Check the wiring harness between A/C-ECU connector C-15 (terminal 5) and outside/inside air selection damper control motor connector C-108 (terminal 4). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 5) and outside/inside air selection damper control motor connector C-108 (terminal 4) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
15. STEP 15. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 6 and ground. OK: 1.5 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 17 . NO : Go to Step 16.
16. STEP 16. Check the wiring harness between A/C-ECU connector C-15 (terminal 6) and outside/inside air selection damper control motor connector C-108 (terminal 5). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 6) and outside/inside air selection damper control motor connector C-108 (terminal 5) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
17. STEP 17. Retest the system. Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

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Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991658: Test Harness Set
4. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, diagnose the CAN bus line. 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. Turn the ignition switch to the "ON" position. Diagnose the CAN bus line. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the CAN bus line found to be normal? YES : Go to Step 2. NO : Repair the CAN bus lines. Refer to «CONTROLLER AREA NETWORK (CAN)»(ref-313851) .
2. STEP 2. Using scan tool MB991958, read the diagnostic trouble code. Check if an A/C-ECU 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 : Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308267-S33679661832009020200000) . NO : Go to Step 3.
3. STEP 3. Using scan tool MB991958, check data list. Connect scan tool MB991958 to the data link connector. Start the engine. Set scan tool MB991958 to the data reading mode. Item 66: Air conditioning switch NOTE: Check that the scan tool displays "ON" when the A/C switch is ON. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the scan tool display "ON" when the A/C switch is on? YES : Go to Step 5 . NO : Go to Step 4.
4. STEP 4. Retest the system. Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
5. STEP 5. Check the refrigerant level. Refer to - On-vehicles service - «REFRIGERANT LEVEL TEST»(ref-308259-S41309497742009020200000) . Q: Is the check result satisfactory? YES : Go to Step 6. NO : Replenish the refrigerant (Refer to - On-vehicle service - «CHARGING»(ref-308259-S11642334012009020200000) ).
6. STEP 6. Check A/C pressure sensor connector A-34 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C pressure sensor connector A-34 in good condition? YES : Go to Step 7. NO : Repair or replace the connector. Refer to - «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
7. STEP 7. Check the A/C pressure sensor operation. Assemble a gauge manifold on the high pressure service valve. Disconnect the A/C pressure sensor connector and connect special tool test harness MB991658 as shown in the illustration. Turn ON the engine and then turn ON the A/C switch. At this time, check to see that the voltage of A/C pressure sensor terminal No. 2 reflects the specifications of the figure. NOTE: The allowance shall be defined as +/-5%. Q: Is the A/C pressure sensor operating properly? YES : Go to Step 8. NO : Replace the A/C pressure sensor.
8. STEP 8. Check A/C-ECU connector C-15 and C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connector C-15 and C-20 in good condition? YES : Go to Step 9. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
9. STEP 9. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and A/C pressure sensor connector A-34, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 12 and A/C pressure sensor connector A-34 terminal 3. OK: Less than 10 ohms Q: Is the check result normal? YES : Go to Step 11 . NO : Go to Step 10.
10. STEP 10. Check the wiring harness between A/C-ECU connector C-15 (terminal 12) and A/C pressure sensor connector A-34 (terminal 3). NOTE: Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 12) and A/C pressure sensor connector A-34 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
11. STEP 11. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and A/C pressure sensor connector A-34, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 26 and A/C pressure sensor connector A-34 terminal 2. OK: Less than 10 ohms Q: Is the check result normal? YES : Go to Step 13 . NO : Go to Step 12.
12. STEP 12. Check the wiring harness between A/C-ECU connector C-20 (terminal 26) and A/C pressure sensor connector A-34 (terminal 2). NOTE: Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 26) and A/C pressure sensor connector A-34 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
13. STEP 13. Measure the resistance at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 24 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 15 . NO : Go to Step 14.
14. STEP 14. Check the wiring harness between A/C-ECU connector C-20 (terminal 26) and A/C pressure sensor connector A-34 (terminal 2). NOTE: Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 26) and A/C pressure sensor connector A-34 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
15. STEP 15. Check A/C compressor assembly connector B-27 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C compressor assembly connector B-27 in good condition? YES : Go to Step 16. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
16. STEP 16. Check the A/C compressor clutch operation. Connect the compressor connector terminal to the battery positive (+) terminal and ground the battery's negative (-) terminal to the compressor unit. At that time, the A/C compressor clutch should make a definite operating sound. Q: Can the sound (click) of the A/C compressor clutch operation be heard? YES : Go to Step 17. NO : Replace the compressor magnet clutch.
17. STEP 17. Check the A/C compressor clutch relay continuity. Follow the table below to check the A/C compressor clutch relay for continuity. CONTINUITY CONDITIONS BATTERY VOLTAGE TESTER CONNECTION SPECIFIED CONDITION Not applied 1-4 Open circuit Connect terminal 2 to the positive battery terminal Connect terminal 3 to the negative battery terminal 1-4 Less than 2 ohms Q: Is the A/C compressor clutch relay in good condition? YES : Go to Step 18. NO : Replace the A/C compressor clutch relay.
18. STEP 18. Check the wiring harness for open circuit. Disconnect A/C compressor clutch relay connector B-17X, and measure the resistance at the wiring harness side. Measure the resistance between A/C compressor clutch relay connector B-17X terminal 1 and ground. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 20 . NO : Go to Step 19.
19. STEP 19. Check the wiring harness between A/C compressor clutch relay connector B-17X (terminal 1) and the battery. NOTE: Also check intermediate connector A-15 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector A-15 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C compressor clutch relay connector B-17X (terminal 1) and the battery in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
20. STEP 20. Check the wiring harness for open circuit. Disconnect A/C compressor assembly connector B-27 and A/C compressor clutch relay connector B-17X, and measure the resistance at the wiring harness side. Measure the resistance between A/C compressor assembly connector B-27 terminal 1 and A/C compressor clutch relay connector B-17X terminal 4. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 22 . NO : Go to Step 21.
21. STEP 21. Check the wiring harness between A/C compressor assembly connector B-27 (terminal 1) and A/C compressor clutch relay connector B-17X (terminal 4). Q: Is the wiring harness between A/C compressor assembly connector B-27 (terminal 1) and A/C compressor clutch relay connector B-17X (terminal 4) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
22. STEP 22. Retest the system. Check that the A/C works normally. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 283

1. Malfunction of connector.
2. Malfunction of the harness (Blower motor circuit is open/damaged/shorted to ground)
3. Malfunction of the blower motor
4. Malfunction of the blower relay
5. Malfunction of the power transistor
6. Malfunction of the A/C-ECU

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. 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. 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 : Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308267-S33679661832009020200000) . NO : Go to Step 2.
2. STEP 2. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 01: Blower fan: OFF Item 02: Blower fan: 8 step Item 03: Blower fan: 16 step Check that the blower motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 4 . NO : Go to Step 3.
3. STEP 3. Retest the system. Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
4. STEP 4. Check the blower relay continuity. Follow the table below to check the blower relay for continuity. CONTINUITY CONDITIONS BATTERY VOLTAGE TESTER CONNECTION SPECIFIED CONDITION Not applied 4-5 Open circuit Connect terminal 1 to the positive battery terminal Connect terminal 3 to the negative battery terminal 4-5 Less than 2 ohms Q: Is the blower relay continuity in good condition? YES : Go to Step 5. NO : Replace the blower relay.
5. STEP 5. Check blower motor connector C-116 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is blower motor connector C-116 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Check the blower fan and motor operation. When battery voltage is applied between the terminals, check that the motor operates. Also, check that there is no abnormal noise. Q: Is there any abnormal noise? YES : Go to Step 7. NO : Replace the blower motor.
7. STEP 7. Check A/C-ECU connector C-15 and power transistor connector C-107 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connector C-15 and power transistor connector C-107 in good condition? YES : Go to Step 8. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
8. STEP 8. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and power transistor connector C-107, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 17 and power transistor connector C-107 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-15 (terminal 17) and power transistor connector C-107 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 17) and power transistor connector C-107 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and power transistor connector C-107, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 18 and power transistor connector C-107 terminal 3. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 12 . NO : Go to Step 11.
11. STEP 11. Check the wiring harness between A/C-ECU connector C-15 (terminal 18) and power transistor connector C-107 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 18) and power transistor connector C-107 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
12. STEP 12. Check the wiring harness for open circuit. Disconnect power transistor connector C-107, and measure the resistance at the wiring harness side. Measure the resistance between power transistor connector C-107 terminal 2 and ground. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 14 . NO : Go to Step 13.
13. STEP 13. Check the wiring harness between power transistor connector C-107 (terminal 2) and ground. Q: Is the wiring harness between power transistor connector C-107 (terminal 2) and ground in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
14. STEP 14. Check the wiring harness for open circuit. Disconnect blower motor connector C-116 and power transistor connector C-107, and measure the resistance at the wiring harness side. Measure the resistance between blower motor connector C-116 terminal 2 and power transistor connector C-107 terminal 4. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 16 . NO : Go to Step 15.
15. STEP 15. Check the wiring harness between blower motor connector C-116 (terminal 2) and power transistor connector C-107 (terminal 4). Q: Is the wiring harness between blower motor connector C-116 (terminal 2) and power transistor connector C-107 (terminal 4) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
16. STEP 16. Check the wiring harness for open circuit. Disconnect blower motor connector C-116 and junction block connector C-202, and measure the resistance at the wiring harness side. Measure the resistance between blower motor connector C-116 terminal 1 and junction block connector C-202 terminal 4. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 18 . NO : Go to Step 17.
17. STEP 17. Check the wiring harness between blower motor connector C-116 (terminal 1) and junction block connector C-202 (terminal 3). Q: Is the wiring harness between blower motor connector C-116 (terminal 1) and junction block connector C-202 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
18. STEP 18. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 17 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 20 . NO : Go to Step 19.
19. STEP 19. Check the wiring harness between A/C-ECU connector C-15 (terminal 17) and power transistor connector C-107 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 17) and power transistor connector C-107 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
20. STEP 20. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 18 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 22 . NO : Go to Step 21.
21. STEP 21. Check the wiring harness between A/C-ECU connector C-15 (terminal 18) and power transistor connector C-107 (terminal 3). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 18) and power transistor connector C-107 (terminal 3) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
22. STEP 22. Replace the power transistor 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.

Scheme 312

1. Malfunction of connector.
2. Malfunction of the harness (Blower motor circuit is shorted to ground)
3. Malfunction of the blower motor
4. Malfunction of the blower relay
5. Malfunction of the power transistor
6. Malfunction of the A/C-ECU

Required Special Tool

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. 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. 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 : Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308267-S33679661832009020200000) . NO : Go to Step 2.
2. STEP 2. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 01: Blower fan: OFF Item 02: Blower fan: 8 step Item 03: Blower fan: 16 step Check that the blower motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 4 . NO : Go to Step 3.
3. STEP 3. Retest the system Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
4. STEP 4. Check the blower relay continuity. Follow the table below to check the blower relay for continuity. CONTINUITY CONDITIONS BATTERY VOLTAGE TESTER CONNECTION SPECIFIED CONDITION Not applied 4-5 Open circuit Connect terminal 1 to the positive battery terminal Connect terminal 3 to the negative battery terminal 4-5 Less than 2 ohms Q: Is the blower relay continuity in good condition? YES : Go to Step 5. NO : Replace the blower relay.
5. STEP 5. Check blower motor connector C-116 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is blower motor connector C-116 in good condition? YES : Go to Step 6. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
6. STEP 6. Check the blower fan and motor operation. When battery voltage is applied between the terminals, check that the motor operates. Also, check that there is no abnormal noise. Q: Is there any abnormal noise? YES : Go to Step 7. NO : Replace the blower relay.
7. STEP 7. Check A/C-ECU connector C-15 and power transistor connector C-107 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connector C-15 and power transistor connector C-107 in good condition? YES : Go to Step 8. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
8. STEP 8. Check the wiring harness for open circuit. Disconnect blower motor connector C-116 and power transistor connector C-107, and measure the resistance at the wiring harness side. Measure the resistance between blower motor connector C-116 terminal 2 and power transistor connector C-107 terminal 4. OK: 1.5 ohm or more Q: Is the check result normal? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between blower motor connector C-116 (terminal 2) and power transistor connector C-107 (terminal 4). Q: Is the wiring harness between blower motor connector C-116 (terminal 2) and power transistor connector C-107 (terminal 4) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Replace the power transistor 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.

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

Scheme 321

1. STEP 1. 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. 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 : Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308267-S33679661832009020200000) . NO : Go to Step 2.
2. STEP 2. Using scan tool MB991958 read the ECM < M/T > or PCM < A/T > diagnostic trouble code. Check whether engine or automatic transaxle DTCs are set or not. Turn the ignition switch to the "ON" position. Check for engine and automatic transaxle DTCs. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES : Go to Step 3. NO : Diagnose the ECM < M/T > or PCM < A/T > (Refer to - Diagnostic Trouble Code - «DIAGNOSTIC TROUBLE CODE CHART»(ref-308262-S12174514092009020200000) < 3.8L ENGINE >).
3. STEP 3. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 77: Condenser fan: 0% Item 78: Condenser fan: 100% Item 79: Condenser fan: 50% Check that the condenser motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 4. NO : Refer to «INSPECTION PROCEDURE 9, THE CONDENSER FAN AND THE RADIATOR FAN DO NOT OPERATE»(ref-308267-S28242774972009020200000) .
4. STEP 4. Check the A/C compressor operation. Does the A/C compressor operate? Q: Is the check result satisfactory? YES : Go to Step 5. NO : Refer to «INSPECTION PROCEDURE 10, THE COMPRESSOR DOES NOT WORK»(ref-308267-S27968596562009020200000)
5. STEP 5. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 42: air mix damper motor 0% (MAX COOL position) Item 43: air mix damper motor 100% (MAX HOT position) Item 44: air mix damper motor 50% (middle position) Check that the air mixing damper control motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 7 . NO : Go to Step 6.
6. STEP 6. Retest the system. Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
7. STEP 7. Check the refrigerant level. Refer to «ON-VEHICLE SERVICE»(ref-308259-S40388441842009020200000) . Q: Is the check result satisfactory? YES : Go to Step 8. NO : Replenish the refrigerant.
8. STEP 8. Retest the system. Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Scheme 322

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. 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. Check if an A/C-ECU 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 : Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308267-S33679661832009020200000) . NO : Go to Step 2.
2. STEP 2. Using scan tool MB991958, check data list. Connect scan tool MB991958 to the data link connector. Start the engine. Set scan tool MB991958 to the data reading mode. Item 06: Photo sensor Cover the photo sensor with your hand or a shop towel. NOTE: Check that the voltage displayed on the scan tool changes. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the voltage displayed on the scan tool change when the photo sensor is covered? YES : Go to Step 3. NO : Go to Step 4 .
3. STEP 3. Retest the system. Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
4. STEP 4. Check A/C-ECU connectors C-15, C-20 and photo sensor connector C-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Are A/C-ECU connectors C-15, C-20 and photo sensor connector C-02 in good condition? YES : Go to Step 5. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Check that the air conditioning works normally.
5. STEP 5. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-15 and photo sensor connector C-02, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-15 terminal 19 and photo sensor connector C-02 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 7 . NO : Go to Step 6.
6. STEP 6. Check the wiring harness between A/C-ECU connector C-15 (terminal 19) and photo sensor connector C-02 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 19) and photo sensor connector C-02 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
7. STEP 7. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and photo sensor connector C-02, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 25 and photo sensor connector C-02 terminal 2. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 9 . NO : Go to Step 8.
8. STEP 8. Check the wiring harness between A/C-ECU connector C-20 (terminal 25) and photo sensor connector C-02 (terminal 2). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 25) and photo sensor connector C-02 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
9. STEP 9. Measure the resistance at A/C-ECU connector C-15. Disconnect A/C-ECU connector C-15, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 19 and ground. OK: 1.5 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 11 . NO : Go to Step 10.
10. STEP 10. Check the wiring harness between A/C-ECU connector C-15 (terminal 19) and photo sensor connector C-02 (terminal 1). Q: Is the wiring harness between A/C-ECU connector C-15 (terminal 19) and photo sensor connector C-02 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
11. STEP 11. Measure the resistance at A/C-ECU connector C-20. Disconnect A/C-ECU connector C-20, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 25 and ground. OK: 1.5 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 13 . NO : Go to Step 12.
12. STEP 12. Check the wiring harness between A/C-ECU connector C-20 (terminal 25) and photo sensor connector C-02 (terminal 2). Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 25) and photo sensor connector C-02 (terminal 2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
13. STEP 13. Replace the photo sensor and check the trouble symptom again. Q: Is the check result normal? YES : The procedure is complete. NO : Replace the A/C-ECU.

Scheme 344

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe
3. MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A

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1. STEP 1. Using scan tool MB991958, diagnose the CAN bus line. 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. Turn the ignition switch to the "ON" position. Diagnose the CAN bus line. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the CAN bus line found to be normal? YES : Go to Step 2. NO : Repair the CAN bus lines. Refer to «CONTROLLER AREA NETWORK (CAN)»(ref-313851) .
2. STEP 2. Using scan tool MB991958, read the diagnostic trouble code. Check if an A/C-ECU 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 : Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308267-S33679661832009020200000) . NO : Go to Step 3.
3. STEP 3. Using scan tool MB991958 read the ECM < M/T > or PCM < A/T > diagnostic trouble code. Check whether an engine and automatic transaxle DTCs are set or not. Turn the ignition switch to the "ON" position. Check for engine and automatic transaxle DTCs. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory? YES : Go to Step 4. NO : Diagnose the powertrain control module (Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-308262-S12174514092009020200000) < 3.8L ENGINE >).
4. STEP 4. Using scan tool MB991958, check actuator test. Connect scan tool MB991958 to the data link connector. Start the engine. Use scan tool MB991958 to run the actuator test. Item 77: Condenser fan: 0% Item 78: Condenser fan: 100% Item 79: Condenser fan: 50% Check that the condenser fan motor operates. Turn the ignition switch to the "LOCK" (OFF) position. Q: Does the motor operate normally? YES : Go to Step 5. NO : Go to Step 6 .
5. STEP 5. Retest the system. Check the trouble symptom again. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.
6. STEP 6. Check the condenser fan motor operation. When battery voltage is applied between the terminals, check that the motor operates. Also, check that there is no abnormal noise. Q: Is there any abnormal noise? YES : Go to Step 7. NO : Diagnose the ECM < M/T > or PCM < A/T > (Refer to - «DIAGNOSTIC TROUBLE CODE»(ref-308262-S37673138052009020200000) < 3.8L ENGINE >).
7. STEP 7. Check A/C pressure sensor connector A-34 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C pressure sensor connector A-34 in good condition? YES : Go to Step 8. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
8. STEP 8. Check the wiring harness for open circuit. Disconnect A/C-ECU connector C-20 and A/C pressure sensor connector A-34, and measure the resistance at the wiring harness side. Measure the resistance between A/C-ECU connector C-20 terminal 34 and A/C pressure sensor connector A-34 terminal 1. OK: Less than 2 ohms Q: Is the check result normal? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between A/C-ECU connector C-20 (terminal 34) and A/C pressure sensor connector A-34 (terminal 1). NOTE: Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between A/C-ECU connector C-20 (terminal 34) and A/C pressure sensor connector A-34 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair the wiring harness.
10. STEP 10. Retest the system. Check that the condenser works normally. Q: Is the check result satisfactory? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Replace the A/C-ECU.

Refer to - SYMPTOM CHART .

Scheme 354

1. Malfunction of the A/C-ECU
2. Malfunction of the rear window defogger relay
3. Damaged harness wires or connectors

Required Special Tools

1. MB991223: Harness Set
2. MB992006: Extra Fine Probe

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1. STEP 1. Check the A/C and outside/inside air selection damper control motor operation. Q: Do the A/C and outside/inside air selection damper control motor work normally? YES : Go to Step 2. NO : Refer to «INSPECTION PROCEDURE 1, MALFUNCTION OF THE A/C-ECU POWER SUPPLY SYSTEM»(ref-308267-S04880889262009020200000) .
2. STEP 2. Check rear window defogger relay connector C-205 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is rear window defogger relay connector C-205 in good condition? YES : Go to Step 3. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
3. STEP 3. Check the rear window defogger relay continuity. Follow the table below to check the rear window defogger relay for continuity. CONTINUITY CONDITIONS BATTERY VOLTAGE CONNECT TESTER BETWEEN SPECIFIED CONDITION Not applied 4-5 Open Circuit Connect terminal 1 to the positive battery terminal Connect terminal 3 to the negative battery terminal 4-5 Less than 2 ohms Q: Is the rear window defogger relay in good condition? YES : Go to Step 4. NO : Replace the rear window defogger relay.
4. STEP 4. Check A/C-ECU connector C-15 and rear window defogger connector F-01 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is A/C-ECU connector C-15 and rear window defogger connector F-01 in good condition? YES : Go to Step 5. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
5. STEP 5. Measure the voltage at rear window defogger connector F-01. Disconnect rear window defogger connector F-01, and measure the voltage at the harness side. Disconnect A/C-ECU connector C-15 and ground harness side terminal No.8. Turn the ignition switch to the "ON" position. Measure the voltage between rear window defogger connector F-01 terminal No.1 and ground. The measured value should be approximately 12 volts (battery positive voltage). Q: Is the measured voltage approximately 12 volts? YES : Go to Step 12 . NO : Go to Step 6.
6. STEP 6. Measure the voltage at rear window defogger relay connector C-205. Disconnect rear window defogger relay connector C-205, and measure the voltage at the junction block side. Measure the voltage between terminal 5 and ground. The measured value should be approximately 12 volts (battery positive voltage). Q: Is the measured voltage approximately 12 volts? YES : Go to Step 8 . NO : Go to Step 7.
7. STEP 7. Check the wiring harness between rear window defogger relay connector C-205 (terminal 5) and the fusible link (1). NOTE: Also check intermediate connector C-24 and junction block connector C-204 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 and junction block connector C-204 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 5) and the fusible link (1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair or replace the wiring harness. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
8. STEP 8. Measure the voltage at rear window defogger relay connector C-205. Disconnect rear window defogger relay connector C-205, and measure the voltage at the junction block side. Turn the ignition switch to the "ON" position. Measure the voltage between terminal 1 and ground. The measured value should be approximately 12 volts (battery positive voltage). Q: Is the measured voltage approximately 12 volts? YES : Go to Step 10 . NO : Go to Step 9.
9. STEP 9. Check the wiring harness between rear window defogger relay connector C-205 (terminal 1) and ignition switch (IG2). NOTE: Also check junction block connector C-202 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-202 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 1) and ignition switch (IG2) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair or replace the wiring harness. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
10. STEP 10. Check the wiring harness between rear window defogger relay connector C-205 (terminal 3) and A/C-ECU connector C-15 (terminal 8). NOTE: Also check junction block connector C-215 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-215 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 3) and A/C-ECU connector C-15 (terminal 8) in good condition? YES : Go to Step 11. NO : Repair or replace the wiring harness. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
11. STEP 11. Check the wiring harness between rear window defogger relay connector C-205 (terminal 4) and rear window defogger connector F-01 (terminal 1). NOTE: Also check junction block connector C-208 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-208 is damaged, repair or replace the connector as described in «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) . Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 4) and rear window defogger connector F-01 (terminal 1) in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair or replace the wiring harness. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
12. STEP 12. Check rear window defogger connector F-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector. Q: Is rear window defogger connector F-04 in good condition? YES : Go to Step 13. NO : Repair or replace the connector. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
13. STEP 13. Measure the resistance at rear window defogger connector F-04. Disconnect rear window defogger connector F-04, and measure the resistance at the wiring harness side. Measure the resistance value between terminal 1 and ground. OK: 1 kohms or more Q: Does the measured resistance value correspond with this range? YES : Go to Step 15 . NO : Go to Step 14.
14. STEP 14. Check the wiring harness between rear window defogger connector F-01 (terminal 1) and ground. Q: Is the wiring harness between rear window rear window defogger connector F-01 (terminal 1) and ground in good condition? YES : It can be assumed that this malfunction is intermittent. Refer to «HOW TO COPE WITH INTERMITTENT MALFUNCTIONS»(ref-308257-S10174114642009020200000) . NO : Repair or replace the wiring harness. Refer to «HARNESS CONNECTOR INSPECTION»(ref-308258-S34323851462009020200000) .
15. STEP 15. Check the rear window defogger. Let the engine run at 2,000 r/min, and check the printed heater with the battery fully charged. Turn on the rear window defogger switch, and use a voltmeter to measure the voltage in each printed heater at middle point A on the rear window glass. The value should be approximately 6 volts. Q: Does the rear window defogger work normally? YES : Replace the A/C-ECU. NO : Repair the rear window defogger.

TROUBLESHOOTING HINT

1. Malfunction of the A/C-ECU
2. Malfunction of the rear window defogger timer

Replace the A/C-ECU.

ACTUATOR TEST REFERENCE

ACTUATOR TEST REFERENCE

Scheme 380

TERMINALS VOLTAGE CONDITIONS