Cooldown Test - ATC And MTC Systems
WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. 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 ELECTRONIC CONTROL MODULES - 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. Refer to ELECTRONIC CONTROL MODULES - ELECTRICAL 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 (Refer to HEATING & AIR CONDITIONING/PLUMBING - DIAGNOSIS AND TESTING - REFRIGERANT SYSTEM LEAKS) .
- 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 evaporator to warm up before proceeding.