Inspection Procedure 15

CIRCUIT OPERATION
- When the A/C is turned ON and the dual pressure switch is closed, PCM (terminal number 83) receives battery positive 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 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
STEP 1. Check The Dual Pressure Switch.
Check the dual pressure switch. Refer to On-vehicle Service - Dual Pressure Switch Check.
If the dual pressure switch is operating properly, go to step 2.
If the dual pressure switch is not operating properly, replace it. Refer to Refrigerant Line.

STEP 2. Check The Dual Pressure Switch Circuit.





1. Disconnect harness connector C-57 <2.4L Engine> or C-59 <3.0L Engine> and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Turn the A/C switch ON.
4. Measure the voltage between terminal 83 and ground.
- Voltage should be battery positive voltage.
If battery positive voltage, go to Step 3.
If not battery positive voltage, go to Step 4.

STEP 3. Check Harness Connector C-57 <2.4L Engine> Or C-59 <3.0L Engine> At The PCM For Damage.





If harness connector C-57 <2.4L Engine> or C-59 <3.0L Engine> is damaged, repair or replace it. Refer to Harness Connector Inspection. Then check for the symptom.
If harness connector C-57 <2.4L Engine> or C-59 <3.0L Engine> is in good condition, repair the harness wires or the connectors between the PCM and the dual pressure switch.

STEP 4. Check The A/C System.
Check the A/C system. Refer to Heater, Air Conditioning and Ventilation Diagnosis - Symptom Chart. Then check for the symptom.
If the symptom is eliminated, diagnosis is complete.
If the symptom is not eliminated, replace the PCM. The immobilizer-ECU and the ignition key should be replaced together with it. Refer to Ignition Switch and Immobilizer System - Ignition Switch and Immobilizer System.