A/C - Blows Warm Air After a Long Drive

The following article has been updated by technical service bulletin (TSB) 64 09 06. This TSB was originally published in August 2006, first revised in October 2006, then revised in May 2009 and most recently revised in September 2010.

SUBJECT
Air Conditioning System Blows Warm Air After Long Drive

MODEL
E90, E91, E92 (3 Series) vehicles produced up to August 15, 2006
E70 (X5) vehicles produced up to February 27, 2009
E71 (X6) vehicles produced up to February 27, 2009

SITUATION
The customer states that the air conditioning system works properly, but after driving on a long trip (approximately more than 1 hour), the system starts to blow warm air. This usually happens under extremely humid conditions. Once the system is turned off for 10 15 minutes, the system starts to cool properly.

CAUSE
Hot air leaks between the evaporator and housing wall, past the evaporator sensor, causing the evaporator sensor to read high.

PROCEDURE
The September 2010 procedure from the TSB is included immediately below:

The contents of this Service Information bulletin have been migrated into ISTA 2.18.0 or later.
1. Perform a vehicle test using ISTA.
2. Complete all test plans that are related to the customer complaint.
3. If no relevant faults are stored, test plan W6450_WAS16 can be found as follows:
- Highlight the "Activities" tab.
- Select the "Function Structure" tab.
- Select "Heating and Air Conditioning" from the list.
- Click on "start" located on the lower right corner of the display.
- Select test plan "W6450_WAS16" from the list of test plans and complete as recommended.

The May 2009 procedure from the TSB is included immediately below:
1. Ensure that the IHKA system is free of faults and correct as necessary. Note: this situation, as outlined in this Service Information, does not set a fault.
2. Remove the evaporator sensor (refer to Repair Instruction REP 64 11 942). Service and Repair






3. Obtain a self-adhesive foam strip (1) from the Parts department.
4. Ensure that the surface of the sensor (2) is clean.






5. Affix the foam strip (1) to the side of the sensor (opposite the electrical connector), as shown to the left between the plastic ribs.
6. Do not cover the sensor tip with the foam strip.
7. To prevent assembly problems, compress the foam strip prior to reinstallation and then install the sensor immediately. The foam strip will expand to its original thickness after installation.
8. Check the system for proper functionality.





PARTS INFORMATION