Diagnostic Routine K
Diagnostic Routine K
Diagnostic Overview
Incorrect or Erratic Direction of Airflow From Outlets
Refer to Wiring Diagram Set 55 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
To rotate the defrost/panel/floor mode door actuator, the HVAC (Heating, Ventilation, and Air Conditioning) module supplies voltage and ground to the defrost/panel/floor mode door actuator motor through the actuator motor circuits. To reverse the defrost/panel/floor mode door actuator rotation, the HVAC (Heating, Ventilation, and Air Conditioning) module reverses the voltage and ground circuits.
The defrost/panel/floor mode door actuator feedback resistor is supplied a 5-volt reference voltage and ground from the HVAC (Heating, Ventilation, and Air Conditioning) module. The HVAC (Heating, Ventilation, and Air Conditioning) module measures the resistance on the defrost/panel/floor mode door actuator feedback circuit to determine the defrost/panel/floor mode door actuator position by the position of the actuator feedback resistor wiper arm.
During an actuator calibration cycle, the HVAC (Heating, Ventilation, and Air Conditioning) module drives the defrost/panel/floor mode door until the door reaches both internal stops in the HVAC (Heating, Ventilation, and Air Conditioning) case. If the defrost/panel/floor mode door is temporarily obstructed or binding during a calibration cycle, the HVAC (Heating, Ventilation, and Air Conditioning) module may interpret this as the actual end of travel for the door. When this condition occurs and the HVAC (Heating, Ventilation, and Air Conditioning) module commands the actuator to its end of travel, the airflow may not be from the expected outlets.
DTC Fault Trigger Conditions
Pinpoint Test
NOTE: Access to the defrost/panel/floor mode door actuator motor connector in this pinpoint test is difficult. Before disconnecting the defrost/panel/floor mode door actuator motor connector, visually inspect the actuator and its harness for obvious damage. If no damage is evident, proceed with the test.
1. CHECK THE HVAC (Heating, Ventilation, and Air Conditioning) MODULE FOR DTCs (Diagnostic Trouble Codes)
1. Ignition ON.
2. Using a scan tool, perform a HVAC (Heating, Ventilation, and Air Conditioning) module self-test.
Are any DTCs (Diagnostic Trouble Codes) present?
2. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR OPERATION USING ACTIVE COMMANDS
1. Ignition ON.
2. Using a scan tool, view HVAC (Heating, Ventilation, and Air Conditioning) module PIDs (Parameter Identifications).
3. Monitor the HVAC (Heating, Ventilation, and Air Conditioning) module PID (Parameter Identification) AIR_MODE_DPOS.
4. Select panel mode.
5. Select the highest blower motor setting.
6. Observe airflow while using the scan tool to operate the HVAC (Heating, Ventilation, and Air Conditioning) module active command AIR_MODE_DPOS, increasing and decreasing the percentage value.
Does the airflow change between the defrost, panel and floor outlets when the active command is changed?
3. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
3. Disconnect: Defrost/Panel/Floor Mode Door Actuator.
4. Measure:
Are the resistances greater than 10,000 ohms?
4. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
3. Disconnect: Defrost/Panel/Floor Mode Door Actuator.
4. Ignition ON.
5. Measure:
Is any voltage present?
5. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TOGETHER
1. Ignition OFF.
2. Disconnect: Defrost/Panel/Floor Mode Door Actuator.
3. Measure:
Is the resistance greater than 10,000 ohms?
6. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR MOTOR CIRCUITS FOR AN OPEN
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
3. Disconnect: Defrost/Panel/Floor Mode Door Actuator.
4. Measure:
Are the resistances less than 3 ohms?
7. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
3. Disconnect: Defrost/Panel/Floor Mode Door Actuator.
4. Measure:
Is the resistance greater than 10,000 ohms?
8. CHECK THE SIGNAL RETURN CIRCUIT FOR A SHORT TO THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR FEEDBACK CIRCUIT
1. Measure:
Is the resistance greater than 10,000 ohms?
9. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
3. Disconnect: Defrost/Panel/Floor Mode Door Actuator.
4. Ignition ON.
5. Measure:
Is any voltage present?
10. CHECK THE REFERENCE VOLTAGE CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Measure:
Is the resistance less than 3 ohms?
11. CHECK THE REFERENCE VOLTAGE CIRCUIT FOR A SHORT TO THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR FEEDBACK CIRCUIT
1. Ignition OFF.
2. Measure:
Is the resistance greater than 10,000 ohms?
12. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR FEEDBACK CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
13. CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR RETURN CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
14. CHECK FOR CORRECT DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR OPERATION
1. Ignition OFF.
2. Disconnect and inspect the defrost/panel/floor mode door actuator connector.
3. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary
4. Reconnect the defrost/panel/floor mode door actuator connector. Make sure it seats and latches correctly.
5. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.
6. Clear the DTCs (Diagnostic Trouble Codes).
7. Operate the system and determine if the concern is still present.
Is the concern still present?
15. MODULE ACTUATOR POSITION CALIBRATION
NOTE: The purpose of the module actuator position calibration is to allow the HVAC (Heating, Ventilation, and Air Conditioning) module to reinitialize and calibrate the actuator stop points.
1. Ignition OFF.
2. Disconnect and inspect all HVAC (Heating, Ventilation, and Air Conditioning) module connectors.
3. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary
4. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.
5. Ignition ON.
6. Clear the DTCs (Diagnostic Trouble Codes).
7. Using a scan tool, perform HVAC (Heating, Ventilation, and Air Conditioning) Module self-test.
8. Select any position except OFF.
9. NOTE: The HVAC (Heating, Ventilation, and Air Conditioning) module initializes and calibrates the actuators. Calibration of the actuators takes approximately 30 seconds.
Operate the system and determine if the concern is still present.
Is the concern still present?
