High HVAC Duct Temperature Variance With AC On - keywords air compressor condition hot intermittent variation warm

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

The customer may complain of a high temperature variance from the HVAC ducts, with the AC on. This will mainly happen when the outside ambient temperature is around 90 F (32 C) or above, and driving under city driving conditions. When the AC compressor cycles off, it may stay off longer than desired and cause the duct temperature to increase until the compressor turns back on.

Reprogram the Engine Control Module (ECM) then the Transmission Control Module (TCM). To ensure both controllers are programmed at the same time select Programming Sequence ECM/TCM on the Supported Controller Screen (Note: This is the last selection in the scroll down box). Refer to SI and Service Programming System (SPS) documentation for ECM and TCM programming instructions, if required.

Note: It is important that the ECM and TCM are both be updated. If both modules are not updated, the odometer function will be affected.

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.