A/C - Incorrect Air Distribution/Temperature Control
Date: April 14, 2008Order No.: T-B-83.00/117
Supercedes:
Group: 83
SUBJECT:
Model 164.122/175/177/186/822/871
Model 251.122/165/175/177
Incorrect Air Distribution or Temperature Control Malfunction of LIN bus / Teach-in Process of Actuator Motors not Possible DTC 9401, 9402, 9403, 9404, 9405, 9406, 9407, 9408, 9409, 9501, 9502, 9503 and 9505
If you receive customer reports in the above model vehicles of incorrect air distribution or temperature control, the cause could be a malfunction in the LIN bus or the teach-in process for the actuator motors has not been performed correctly. To resolve, refer to the below respective remedy(s).
Cause for Malfunction of the LIN Bus:
One or more of the LIN bus components and /or the wiring to the component is faulty and causes the entire communication in the bus to be interrupted.
Remedy:
1. Print out the fault code log using Star Diagnosis.
2. Go to Star Tekinfo --> EDAC --> non-EDAC guides --> HVAC System Manual --> Model 164 or 251 System Overview and locate the LIN bus schematic. The LIN bus is a series circuit. The starting point for diagnosing a fault should be the first component in the circuit with a DTC.
3. Check Workshop 1 Coding (Figure 1). Ensure all components listed are correctly coded.
4. Check if actuator motor M16/27 for reducing the temperature at the center vent is coded present or not present. This actuator was deleted in production starting 6/5/07.
5. Check for correct Vehicle Model AC coding (580, 581, 581 and 582) (Figure 2).
6. After replacing one or more actuators motors perform teach in process for all the actuator motors.
Note:
Teach in process may need to be activated more than one time in order for it to complete successfully.
7. After a successful teach in, normalize all the motors.
Note:
During normalization, the progress bar does not move all the way to the end.
Causes for Teach-in Process of Actuator Motors Not Possible: Components not present coded as present in the LIN bus. Incorrect Vehicle Model AC coding (580, 581, 581 + 582) may be coded in the AC operating unit.
Remedy:
1. Print out the fault code log using Star Diagnosis.
2. Check Workshop 1 Coding (Figure 1). The bold selections must be coded correctly.
3. Check if actuator motor M16/27 for reducing the temperature at the center vent is coded present or not present. This actuator was deleted starting with 6/5/07 production.
4. Check for correct Vehicle Model AC coding (580, 581, 581and 582) (Figure 2).
5. Ensure that no current fault codes are stored in the ACC control unit.
6. Perform the teach-in process of the actuator motors. Note: Teach in process may need to be activated more than one time in order for it to complete successfully.
7. After a successful teach in, normalize all the motors.
Note:
During normalization, the progress bar does not move all the way to the end.