Starting The Cooldown Test - ATC System

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.

Once all of the prerequisites have been met, the Cooldown Test for the ATC system can be actuated by sending a command with a scan tool. Once started, the ATC A/C-heater control automatically sets the blower speed and positions the air-doors for optimal A/C performance. It also sends a request for A/C operation on the CAN B bus. The Cooldown Test can take up to two minutes to run and, will stop running if any of the following occurs:

The ignition is turned off.
The A/C compressor is requested off.
The blower motor control is moved to the Off position, unless the control was in the Off position when the Cooldown Test was started. In this case, moving the blower motor control out of the Off position and then returning it to the Off position will stop the test.
DTC B1031 or B1032 sets during the Cooldown Test.
The A/C-heater control receives a bus message to stop the Cooldown Test.

While the Cooldown Test is running, the A/C status indicator will flash. During this time the A/C-heater control will ignore most of its inputs. If the ATC system passes the test, the A/C status indicator will stop flashing. However, if the ATC system fails the test, both the A/C and EBL status indicators will flash alternately and an active DTC B10B2 will set. The status indicators will continue to flash until either a successful Cooldown Test is executed or until the vehicle is driven a specified number of miles. In addition, DTC B10B2 will remain active until a successful Cooldown Test is executed. Always check for DTCs in the A/C-heater control after running the Cooldown Test.