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Home >> Mitsubishi >> 2001 >> Montero XLS >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Diagnosis - R4A51, V4A51 & V5A51 >> Symptom Tests >> Test O: Vehicle Shifts Differently With A/C Engaged >> Diagnostic Procedure (Montero Sport)

Diagnostic Procedure (Montero Sport)

NOTE: For circuit identification see Fig 1 .
  1. Using scan tool, monitor dual pressure switch. When the A/C is in operation, the scan tool display should indicate ON. When the A/C is not in operation, the scan tool display should indicate OFF. Is the dual pressure switch operating properly? If so, malfunction is intermittent. If not, go to next step.
  2. Check dual pressure switch harness connector for damage. Is the harness connector in good condition? If so, go to next step. If not, repair or replace defective harness connector.
  3. Check the power supply voltage at dual pressure switch harness connector. Disconnect dual pressure switch harness connector and measure at the harness side. Start the engine and run at idle. Measure the voltage between dual pressure switch harness connector terminal No. 1 and ground. Battery voltage should exist. Turn ignition off. Is the voltage as specified? If so, go to step  9 . If not, go to next step.
  4. Check the power supply voltage at automatic compressor controller harness connector C-09 by backprobing. Do not disconnect harness connector. Start the engine and run at idle. Operate the air conditioning. Measure the voltage between automatic compressor controller harness connector C-09 terminal No. 2 and ground. Battery voltage should exist. Turn ignition off. Is the voltage as specified? If so, go to step  8 . If not, go to next step.
  5. Check automatic compressor harness controller C-09 and intermediate harness connector C-41 for damage. Are the harness connectors in good condition? If so, go to next step. If not, repair or replace the defective harness connector(s).
  6. Check wire harness for short to ground between dual pressure switch harness connector terminal No. 1 and automatic compressor controller harness connector C-09 terminal No. 2. Is the wire harness in good condition? If so, go to next step. If not, repair wire harness as necessary.
  7. Using scan tool, monitor dual pressure switch. When the A/C is in operation, the scan tool display should indicate ON. When the A/C is not in operation, the scan tool display should indicate OFF. Turn ignition off. Is the dual pressure switch operating properly? If so, malfunction is intermittent. If not, check the air conditioning system. See appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
  8. Check automatic compressor controller harness connector C-09 and intermediate harness connector C-41 for damage. Are the harness connectors in good condition? If so, repair open in wire harness between automatic compressor controller harness connector C-09 terminal No. 2 and dual pressure switch harness connector terminal No. 1. If not, repair or replace the defective connector(s).
  9. Check the dual pressure switch output voltage at PCM harness connector by backprobing. Do not disconnect harness connector. Start the engine and run at idle. Operate the air conditioning. Measure the voltage between PCM harness connector terminal No. 83 and ground. When the air conditioning is in operation, battery voltage should exist. When the air conditioning is not in operation, the voltage should be 0.5 volt or less. Turn ignition off. Is the voltage as specified? If so, go to step  15 . If not, go to next step.
  10. Check PCM harness connector, A/C refrigerant temperature switch harness connector A-25 and intermediate harness connector A-89 for damage. Are the harness connectors in good condition? If so, go to next step. If not, repair or replace the defective harness connector(s).
  11. Check wire harness for short to ground or open between dual pressure switch harness connector A-23 terminal No. 2 and PCM harness connector terminal No. 83. Is the wire harness in good condition? If so, go to next step. If not, repair wire harness as necessary.
  12. Check the dual pressure switch. See DUAL PRESSURE SWITCH  under COMPONENT TESTS. Is the dual pressure switch operating properly? If so, go to next step. If not, replace the dual pressure switch. See appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
  13. Check the A/C refrigerant temperature switch. Check for continuity between the refrigerant temperature switch terminals. Continuity should exist. Does continuity exist between the refrigerant temperature switch terminals? If so, go to next step. If not, replace the compressor assembly.
  14. Using scan tool, monitor dual pressure switch. When the A/C is in operation, the scan tool display should indicate ON. When the A/C is not in operation, the scan tool display should indicate OFF. Is the dual pressure switch operating properly? If so, malfunction is intermittent. If not, possible faulty PCM exists. Replace the PCM if necessary. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION.
  15. Check PCM harness connectors for damage. Are the harness connectors in good condition? If so, go to step  14 . If not, repair or replace defective harness connector(s).
Fig 1: Identifying Dual Pressure Switch System Circuit (Montero Sport)
G00148957Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
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