Poor HVAC Performance After BCM Replacement A/C Compressor Cycles (Program BCM Using VCI Number) - keywords 07237 AC air BCM C60 C68 condition cycle ECM HVAC inop inoperative int intermittent manual

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customers may complain about their HVAC system performance noting it doesn't cool as well after the BCM was replaced.

The concern is that the service replacement BCM comes programmed for C68 (automatic climate control) and usually the BCM is set up using the Tech2. However, due to a software change in the MY08 BCM, the Tech2 is not able to set the C60 bit in the BCM even though it looks like it has been changed. This creates a communication concern with the ECM which then cycles the compressor causing an HVAC performance concern.

Note: Until the Tech2 is updated (approximately 11/1/07) anytime a BCM is replaced the following service procedure will need to be performed to make sure the customer complaint does not occur.

Follow the service instructions in Service Update bulletin 07237 to correctly program the BCM for a C60 vehicle by obtaining a VCI number.

Note: Other BCM options such as RFA will still need to be set up using the Tech2

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.