Control Assembly, HVAC

2, 5








Fault symptoms
Cannot adjust heating on left-hand side.

Conditions
The following conditions apply:
- During calibration, the stepping motor is run the number of steps that corresponds to the distance between the flap's end positions, plus a number of extra steps.
In this way, the control module is aware that the flap is in an end position.
- If the current consumption does not increase to a value corresponding to a jammed motor, i.e. the flap is physically at an end position, diagnostic trouble code 2 is set: Loose flap.
- Calibration continues with the control module returning the stepping motor the number of steps equal to the distance to the opposite end position. If the control module detects that the flap is jammed before the motor has moved the correct number of steps, diagnostic trouble code 5 is set: Flap jammed.





Diagnostic procedure

1. Checking the motor operation
- Remove the motor in question and run it by turning the knob on the MCC panel.





- The motor should move when activated.

Is the function correct?
YES
- Go to step 2
NO
- Replace the motor in question.
- Go to step 3.





2. Checking for mechanical interference
- Check the mechanical function of the flap.

Is the function correct?
YES
- Restore the car to normal and calibrate.
- Go to step 3.
NO
- Rectify the fault.
- Go to step 3.





3. Final check
- Calibrate the control panel.





- Delete diagnostic trouble codes in all systems.





- Read out the diagnostic trouble codes in the MCC and perform a function check.

Is the function correct?.
YES
- The steps taken to rectify the fault were correct.
NO
- See "Before changing a control module." Before Changing a Control Module