Automatic Climate Control, ACC

B2490








Heater flap motor left. Open circuit
Heater flap motor left. Short circuit

Fault symptoms
The perceived cabin temperature is too high or too low compared to the set temperature.

Conditions
The following conditions apply:
- When the current on one of the control module stepping motor outputs exceeds a certain value, the diagnostic trouble code for short circuit will be set.
- If one of the stepping motor outputs detects that the standing current is lower than 55 mA, then the diagnostic trouble code for open circuit is set.
- Continuous monitoring and when calibrating.





Diagnostic procedure

1. Checking operating current to stepping motor winding 1
- Unplug connector: Motor, temperature flap LH: (222LH).





- Connect a test lamp between pins 1 and 3 on the female connector.





- Operate the calibration function to run the stepping motor.





- Both the red and the green LED should light up on the test lamp.

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





2. Checking operating current to stepping motor winding 2
- Connect a test lamp between pins 4 and 6 on the female connector.





- Operate the calibration function to run the stepping motor.





- Both the red and the green LED should light up on the test lamp.

Is the function correct?
YES
- Replace Motor, temperature flap LH.
- Go to step 3.
NO
- Rectify lead in question.
- Go to step 3.





3. Final check
- Delete diagnostic trouble codes in all Systems.





- Carry out a function check.
- Evaluate the function check.
- Check that the diagnostic trouble code does not recur.

Does the diagnostic trouble code recur?
YES
- See "Before changing a control module." Before Changing a Control Module

NO
- The steps taken to rectify the fault were correct.