Automatic Climate Control, ACC

B2290








Heater flap motor right. Open circuit
Heater flap motor right. Short circuit

Fault symptoms
The perceived cabin temperature is too low compared to the set temperature. The right-hand side cabin temperature cannot be adjusted.

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 control voltage to motor
- Unplug connector: Motor, temperature flap, RH (222RH).





- 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 the control voltage
- 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, RH
NO
- 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.