System Diagnosis - Variable Displacement Orifice Tube (VDOT)

The procedures in the following charts will help you diagnose V5 compressor and VDOT refrigerant system problems causing insufficient cooling. They must be used in conjunction with other appropriate service manual information.

The V5 compressor is a variable displacement compressor which matches air conditioning demand by changing its stroke., instead of cyling its clutch. A control valve location in the the rear head of the compressor senses compressor low side pressure and causes the compressor mechanism to change stroke. Because the V5 compressor always runs and the system does not cycle, these diagnostic procedures differ from those used for fixed displacement systems. By using these procedures you will avoid needlessly replacing A/C components.

Preform the following Preliminary Checks, repair as necessary, if this does not return the system back to normal operation refer to Fig. 7 (parts 2-8) for system troubleshooting procedures.

Check: - A/C fuse.
- A/C blower operation.
- Clutch coil and rear head switch(es) connections.
- Compressor belt.
- Engine cooling fan operation.
- Condenser, check for restricted air flow.

Fig. 7.2 Troubleshooting Chart (Part 2 Of 8).:

Fig. 7.2 Chart: Checking Refrigerant Charge.

Fig 7.3 Troubleshooting Chart (Part 3 Of 8).:

Fig. 7.3 Chart: Checking Compressor Clutch Engagement.

Fig. 7.4 Troubleshooting Chart (Part 4 Of 8).:

Fig. 7.5 Troubleshooting Chart (Part 5 Of 8).:

Figs. 7.4 & 7.5 Charts: Checking System Performance.

Fig. 7.6 Troubleshooting Chart (Part 6 Of 8).:

Fig. 7.6 Chart: Gray area Diagnosis and Service.

Fig. 7.7 Troubleshooting Chart (Part 7 Of 8).:

Fig. 7.7 Chart: Striped area Diagnosis and Service.

Fig. 7.8 Troubleshooting Chart (Part 8 Of 8).:

Fig. 7.8 Chart: Control Valve Diagnosis.