CLEARING FAULTS - MTC SYSTEM
To clear DTCs stored in the A/C-heater control of the MTC system, perform the following:
NOTE: An active DTC 33 will prevent the control
from entering diagnostic mode and performing
certain diagnostic functions. It will also prevent
proper A/C mode switch and status indicator func-
tion. If this occurs, refer to *A/C HEATER CON-
TROL WILL NOT
ENTER
DIAGNOSTIC
MODE
(MTC) in 24 - HVAC - Electrical Diagnostics for the
diagnostic test procedure.
NOTE: An active DTC 34 will prevent the control
from performing certain diagnostic functions and
it will prevent proper EBL mode switch and status
indicator function. If active, diagnose and repair
DTC 34 before proceeding. Refer to 24 - HVAC -
Electrical Diagnostics for the diagnostic test pro-
cedure.
1. Turn the ignition to the On position.
2. Turn the blower motor control (1) to the On posi-
tion.
3. Press the A/C mode switch (2) down, turn the blower motor control to the Off position, wait 5 seconds and then
release the A/C mode switch.
4. When the A/C status indicator begins flashing DTCs, set the Mode switch to the floor position, simultaneously
press the A/C mode switch and the EBL mode switch down for 5 seconds and then release the mode switches.
Stored DTCs will clear from memory in approximately two seconds.
SYSTEM TESTS
HVAC SYSTEM TEST - ATC AND MTC SYSTEMS
The HVAC System Test, found in 24 - HVAC - Electrical Diagnostics, provides a starting point in the diagnostic
process by identifying the appropriate diagnostic procedure or system test to perform when diagnosing a given
symptom, condition, or DTC. It also provides a means for testing the entire HVAC system by utilizing the A/C-heater
control’s On-Board System Tests. The On-Board System Tests can also assist in diagnosing stored DTCs.
ACTUATOR CALIBRATION - ATC SYSTEM
The Actuator Calibration function homes and repositions the air-door actuators, removes accumulated positioning
errors, and checks for air-door span faults. Once actuated, the entire process takes approximately 90 seconds.
Upon completion, all air-door actuators should return to the position that the system is currently requesting. Running
the Actuator Calibration function is the only way to detect air-door travel too large faults and air-door travel too small
faults. These faults, if present, will display on the scan tool after running the Actuator Calibration function.
STARTING ACTUATOR CALIBRATION - ATC SYSTEM
Use a scan tool to start the Actuator Calibration function.
ACTUATOR CALIBRATION - MTC SYSTEM
NOTE: Diagnose and repair Actuator Circuit Test faults (DTC 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, and 72)
before diagnosing Overcurrent faults (DTC 41, 42, 43, and 44) and Calibration faults (DTC 18, 21, 22, 23, 24,
25, 45, 46, 47, 48, 51, 52, 53, 54, 55, and 56). Diagnose and repair Overcurrent faults (DTC 41, 42, 43, and 44)
before diagnosing Calibration faults (DTC 18, 21, 22, 23, 24, 25, 45, 46, 47, 48, 51, 52, 53, 54, 55, and 56).
24 - 368
HVAC - SERVICE INFORMATION
WK