Insufficient Cooling

TROUBLE DIAGNOSIS


Insufficient Cooling

SYMPTOM: Insufficient cooling

INSPECTION FLOW











PERFORMANCE TEST DIAGNOSIS





















PERFORMANCE CHART

Test Condition
Testing must be performed as follows:






Test Reading (VQ35HR)






Test Reading (VK45DE)






TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE
Whenever system's high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the standard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air temperature-to-operating pressure table).

Both High- and Low-pressure Sides are Too High






High-pressure Side is Too High and Low-pressure Side is Too Low






High-pressure Side is Too Low and Low-pressure Side is Too High






Both High- and Low-pressure Sides are Too Low






Low-pressure Side Sometimes Becomes Negative






Low-pressure Side Becomes Negative






DIAGNOSIS PROCEDURE FOR INSUFFICIENT COOLING
SYMPTOM: Insufficient cooling
1.CHECK POWER SUPPLY FOR ECV (ELECTRONIC CONTROL VALVE)
1. Disconnect compressor (ECV) connector.
2. Turn ignition switch ON.





3. Check voltage between compressor (ECV) harness connector
F34 terminal 2 and ground.

2 - ground: Battery voltage

OK or NG
OK - GO TO 2.
NG - Check power supply circuit and 10A fuse [No. 12, located in the fuse block (J/B)]. Fuse Block - Junction Box (J/B).
- If fuse is OK, check harness for open circuit. Repair or replace if necessary.
- If fuse is NG, check harness for short circuit and replace fuse.
2.CHECK ECV CONTROL SIGNAL
1. Turn ignition switch OFF.
2. Reconnect compressor (ECV) connector.
3. Perform self-diagnosis. Self-Diagnosis Function.
4. Set in self-diagnosis STEP-4 (Code No. 45). Self-Diagnosis Function.





5. Confirm ECV control signal between unified meter and A/C amp. harness connector M65 terminal 65 and ground using an oscilloscope.
OK or NG
OK - Replace compressor.
NG - GO TO 3.
3.CHECK CIRCUIT CONTINUITY BETWEEN ECV AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect compressor (ECV) and unified meter and A/C amp. connector.





3. Check continuity between compressor (ECV) harness connector
F34 terminal 3 and unified meter and A/C amp. harness connector M65 terminal 65.

3 - 65: Continuity should exist.

OK or NG
OK - GO TO 4.
NG - Repair harness or connector.
4.CHECK ECV





Check continuity between compressor (ECV) connector F34 terminals 2 and 3.

2 - 3: Continuity should exist.

OK or NG
OK - Replace unified meter and A/C amp.
NG - Replace compressor.