B1079
B1079-CLIMATE CONTROL COOL DOWN TEST EXCESSIVE TIME
For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.
Theory of Operation
The Cool-down Test checks A/C system performance based on Evaporator Temperature Sensor input. The main criteria is to lower evaporator temperature 11.11°C (20°F) within one minute. Before starting the test, the evaporator temperature must be above 18.3°C (65°F) and the blower speed must be set to high speed. When the test is running, A/C Select and A/C Request will be on and the A/C status indicator will flash. When the test is complete, the scan tool will display one or more test status messages to indicate the outcome of the Cool-down Test. A Successful Cool-down - Test Passed status message indicates that the main test criteria was met. A DTC Set During Routine - Test Not Passed status message indicates that the A/C system is unable to lower the evaporator temperature 11.11°C (20°F) within one minute. A Conditions Too Cold - Test Not Run status message indicates that the evaporator temperature was below 18.3°C (65°F) when starting the Cool-down Test. A Blowers Not On High - Test Not Run status message indicates that either the blower speed was not set to high speed prior to starting the Cool-down Test or the blower speed was changed from high speed to another setting after starting the Cool-down test. A Refrigerant Temperature Sensor Error status message indicates that a fault occurred with the Evaporator Temperature Sensor/sensor circuits. A No Results Stored/Test Not Complete status message indicates that the power was cycled while the test was running.
- When Monitored:
When the Cool-down Test is executed.
- Set Condition:
If the A/C system is unable to lower the evaporator temperature 11.11°C (20°F) within one minute.
1. DIAGNOSE COOL-DOWN TEST STATUS MESSAGES
Were any of the following status messages present after performing the Cool-down Test?
Yes, Conditions Too Cold - Test Not Run
- If running, turn the A/C compressor off. Verify that the work area ambient temperature is above 15.6°C (60°F). If not, move the vehicle to a warmer work area. Verify that the evaporator temperature is above 18.3°C (65°F). If not, set the blower to high speed and allow the blower to run for five minutes. Then, run the Cool-down Test again.
Yes, Blowers Not On High - Test Not Run
- Set the blower speed to high speed and then run the Cool-down Test again.
Yes, No Results Stored/Test Not Complete
- Verify that power is not interrupted while rerunning the Cool-down Test.
No
- Go To 2
2. CHECK FOR DTCs IN THE A/C HEATER CONTROL MODULE
1. Turn the ignition on.
2. With the scan tool, read HVAC DTCs.
Excluding B1079-Climate Control Cool Down Test Excessive Time, are any DTCs present in the A/C Heater Control Module?
Yes
- Diagnose and Repair the DTCs. Run the Cool-down Test again after the repair is complete.
- Perform the BODY VERIFICATION TEST. Body Verification Test
No
- Go To 3
3. CHECK FOR DTCs IN THE PCM
1. With the scan tool, read PCM DTCs.
Are any DTCs present in the PCM?
Yes
- Diagnose and repair the DTCs. Testing and Inspection for PCM DTCs. Run the Cool-down Test again after the repair is complete.
- Perform the BODY VERIFICATION TEST. Body Verification Test
No
- Refer to the Service Information for additional Cool-down Test related diagnostic information and testing procedures. Run the Cool-down Test again after the repair is complete.
- Perform the BODY VERIFICATION TEST. Body Verification Test