Cooldown Time Excessive Fault (MTC)

COOLDOWN TIME EXCESSIVE FAULT (MTC)

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
When the Cooldown Test is executed.

- Set Condition:
If the A/C system is unable to lower Evaporator temperature 11.11°C (20°F) within two minutes.





Diagnostic Test

1. VERIFY ALL COOLDOWN TEST PREREQUISITES WERE MET & RUN THE TEST AGAIN
NOTE: The following are prerequisites of the Cooldown Test. Verify each of the following before running the test:
- If active, diagnose and repair DTC Evaporator Temperature Sensor Circuit Open or DTC Evaporator Temperature Sensor Circuit Shorted before proceeding.
- Verify that the refrigerant system has an adequate charge. Check and repair as necessary before proceeding.
- Verify that the blower motor operates correctly in all speeds. Diagnose and repair all blower related faults before proceeding.
- Verify that the work area ambient temperature is above 21.1°C (70°F) before proceeding. Move the vehicle to a warmer work area if necessary.
- Verify that the evaporator temperature is above 12.7°C (55°F) before proceeding.
- Verify that the A/C compressor is not running. If the A/C compressor is running, turn the A/C off and allow the evaporator to warm up before proceeding.


Once all of the prerequisites have been met, start the engine, set the Blower Control to High, and actuate the Cooldown Test with the scan tool.

NOTE: The Cooldown Test can take up to two minutes to run. While the test is running, the A/C status indicator will flash. If the test fails, the status indicator will continue to flash until either a successful test is performed, or any button on the control is pressed, or the ignition is cycled and the odometer displays more than eight miles. When the test is complete, the scan tool will display one or more test status messages to indicate the outcome of the test. These messages will clear from memory, so note all messages before exiting the test.

Allow the test to run to completion before proceeding.
Does the scan tool display any of the following status messages?

Yes, Blower Not On High

- Refer to Blower Not On High (MTC) for the diagnostic test procedure. Blower Not On High (MTC)

Yes, Cooldown Test Sensor Failure

- Refer to Cooldown Test Sensor Failure (MTC) for the diagnostic test procedure. Cooldown Test Sensor Failure (MTC)

Yes, Cooldown Test Too Cold To Start

- Refer to Cooldown Test Too Cold To Start (MTC) for the diagnostic test procedure. Start from Step 2 of that diagnostic procedure. Cooldown Test Too Cold Too Start (MTC)

No

- Go To 2

2. CHECK FOR HVAC DTCs
Ignition on, engine not running.
With the scan tool, read HVAC DTCs.
Does the scan tool display any DTCs?

Yes

- Diagnose and Repair the DTC(s).
- Run the Cooldown Test after the repair is complete.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To 3

3. CHECK FOR BCM DTCs
With the scan tool, read BCM DTCs.
Does the scan tool display any DTCs?

Yes

- Diagnose and repair the DTC(s).
- Run the Cooldown Test after the repair is complete.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To 4

4. CHECK FOR PCM DTCs
With the scan tool, read PCM DTCs.
Does the scan tool display any DTCs?

Yes

- Diagnose and repair the DTC(s).
- Run the Cooldown Test after the repair is complete.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Refer to the Cooldown Test related diagnostic information and testing procedures. A/C Cool Down Test
- Run the Cooldown Test after the repair is complete.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.