Cooldown Test - ATC And MTC Systems
WARNING: This page is about a different car, the 2010 Dodge Charger and 2010 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
The Cooldown Test checks A/C system performance by measuring the system's ability to lower the evaporator temperature 11.11° C (20° F) as measured by the evaporator temperature sensor. The following are prerequisites of the Cooldown Test. Verify each of the following before running the Cooldown Test:
- For the ATC system, the Cooldown Test will NOT start if DTC B1031 or B1032 is active. If active, diagnose and repair either DTC before proceeding (Refer to 24 - HVAC - Electrical Diagnostics for a complete list of HVAC related symptoms).
- For the MTC system, the Cooldown Test will NOT start if DTC 31 or 32 is active. If active, diagnose and repair either DTC before proceeding (DTC Based Diagnostics for a complete list of HVAC related symptoms).
- For both systems, verify that the refrigerant system has an adequate charge. Check and repair as necessary before proceeding. See Heating and Air Conditioning - Diagnosis and Testing .
- For both systems, verify that the blower motor operates correctly in all speeds. Diagnose and repair all blower motor related faults before proceeding.
- For both systems, verify that the ambient temperature of the work area is above 18.3° C (65° F) before proceeding. Move the vehicle to a warmer work area if necessary.
- For both systems, verify that the evaporator temperature is above 18.3° C (65° F) before proceeding.
- For both systems, verify that the A/C compressor is NOT running. If the A/C compressor is running, turn the A/C off and allow the A/C evaporator to warm up before proceeding.