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Home >> Mitsubishi >> 2004 >> Eclipse V6-3.0L SOHC >> Repair and Diagnosis >> Transmission and Drivetrain >> Transmission Control Systems >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Symptom Diagnosis Charts >> Inspection Procedure 15

Inspection Procedure 15

INSPECTION PROCEDURE 15: Vehicle Shifts Differently with A/C Engaged

Part 1 Of 2:




Part 2 Of 2:






CIRCUIT OPERATION
^ When the A/C is turned ON and the dual pressure switch is closed, PCM (terminal number 83) receives battery voltage and then determines the A/C compressor has been signaled to engage.
^ When the A/C compressor is engaged, the PCM increases line pressure and briefly delays shift points to compensate for the additional engine load.

COMMENT
The cause is probably a faulty dual pressure switch circuit or a defective PCM.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
^ Malfunction of the dual pressure switch
^ Damaged harness, connector
^ Malfunction of A/C system
^ Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
^ MB991958: Scan Tool (MUT-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: MUT-III USB Cable
^ MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, check data list item 65: Dual Pressure Switch.

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.





1) Connect scan tool MB991958 to the data link connector.
2) Start the engine and run at idle.
3) Set scan tool MB991958 to data reading mode for item 65: Dual Pressure Switch.
^ When the A/C is in operation, the scan tool MB991958 display should be "ON."
^ When the A/C is not in operation, the scan tool MB991958 display should be "OFF."
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 2.

STEP 2. Check dual pressure switch connector A-36 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q: Are the connectors and terminals in good condition?
YES: Go to Step 3.
NO: Repair or replace the damaged components.

STEP 3. Measure the power supply voltage at dual pressure switch connector A-36.





1) Disconnect the connector A-36 and measure et the harness side.
2) Start the engine and run at idle.
3) Operate the A/C.





4) Measure the voltage between terminal 2 and ground.
^ Voltage should measure battery positive voltage.
5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage?
YES: Go to Step 10.
NO: Go to Step 4.

STEP 4. Measure the power supply voltage at automatic compressor controller connector C-12 by backprobing.





1) Do not disconnect connector C-12.
2) Start the engine and run at idle.
3) Operate the A/C.





4) Measure the voltage between terminal 4 and ground by backprobing.
^ Voltage should measure battery positive voltage.
5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage?
YES: Go to Step 8.
NO: Go to Step 5.

STEP 5. Check automatic compressor controller connector C-12 and intermediate connector C-94 for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are the connectors and terminals in good condition?
YES: Go to Step 6.
NO: Repair or replace the damaged components.

STEP 6. Check the harness for short circuit to ground between dual pressure switch connector A-36 terminal 2 and automatic compressor controller connector C-12 terminal 4.








Q: Is the harness wire in good condition?
YES: Go to Step 7.
NO: Repair or replace the harness wire.

STEP 7. Using scan tool MB991958, check data list item 65: Dual Pressure Switch.

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.





1) Connect scan tool MB991958 to the data link connector.
2) Start the engine and run at idle.
3) Set scan tool MB991958 to data reading mode for item 65: Dual Pressure Switch.
^ When the A/C is in operation, the scan tool display should be "ON."
^ When the A/C is not in operation, the scan tool display should be "OFF."
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Check the air conditioning system.

STEP 8. Check automatic compressor controller connector C-12 and intermediate connector C-94 for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are the connectors and terminals in good condition?
YES: Go to Step 9.
NO: Repair or replace the defective connector(s).

STEP 9. Check the harness for open circuit between dual pressure switch connector A-36 terminal 2 and automatic compressor controller connector C-12 terminal 4.








Q: Is the harness wire in good condition?
YES: Go to Step 14.
NO: Repair or replace the harness wire.

STEP 10. Measure the switch output voltage at PCM connector C-57 <2.4L Engine> or C-59 <3.0L Engine> by backprobing.





1) Do not disconnect connector C-57 <2.4L Engine> or C-59 <3.0L Engine>.
2) Start the engine and run at idle.
3) Operate the A/C.





4) Measure the voltage between terminal 83 and ground by backprobing.
^ When the A/C is in operation, the voltage should measure battery positive voltage.
5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage?
YES: Go to Step 15.
NO: Go to Step 11.

STEP 11. Check PCM connector C-57 <2.4L Engine> or C-59 <3.0L Engine>, intermediate connector C-28 and C-94 for loose, corroded or damaged terminals, or terminals pushed back in the connector.











Q: Are the connectors and terminals in good condition?
YES: Go to Step 12.
NO: Repair or replace the damaged components.

STEP 12. Check harness for short circuit to ground or open circuit between dual pressure switch connector A-36 terminal 1 and PCM connector C-57 <2.4L Engine> or C-59 <3.0L Engine> terminal 83.








Q: Is the harness wire in good condition?
YES: Go to Step 13.
NO: Repair or replace the harness wire.

STEP 13. Check the dual pressure switch.
Q: Is the switch operating properly?
YES: Go to Step 14.
NO: Replace the dual pressure switch.

STEP 14. Using scan tool MB991958, check data list item 65: Dual Pressure Switch.

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.





1) Connect scan tool MB991958 to the data link connector.
2) Start the engine and run at idle.
3) Set scan tool MB991958 to data reading mode for item 65: Dual Pressure Switch.
^ When the A/C is in operation, the scan tool display should be "ON."
^ When the A/C is not in operation, the scan tool display should be "OFF."
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Replace the PCM.

STEP 15. Check PCM connector C-57 <2.4L Engine> or C-59 <3.0L Engine> for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q: Are the connectors and terminals in good condition?
YES: Go to Step 14.
NO: Repair or replace the damaged components.



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