A/C - System Unable to Maintain Desired Temperature
TECHNICALBulletin No.: 07-01-39-008A
Date: April 17, 2009
Subject:
HVAC System Unable to Maintain Desired Temperature Inside Vehicle (Update HVAC Control Module Software)
Models:
2007 Chevrolet Monte Carlo
2007-2008 Chevrolet Impala
with Manual Control HVAC System (RPO C67) or Manual Control HVAC System (RPO CJ3)
Supercede:
This bulletin is being revised to update RPO Information. Please discard Corporate Bulletin Number 07-01-39-008 (Section 01 - HVAC).
Condition
Some customers may comment that the temperature selected on the HVAC control head is not being maintained inside the vehicle.
Cause
This condition may be caused by the temperature doors losing their positions.
Correction
Important
There are two calibrations part numbers that are valid for HVAC. Read the descriptions and RPO Codes to determine the correct calibration for your vehicle.
A new calibration has been released that periodically relearns the temperature door positions and prevents the doors from becoming lost. Technicians are to reprogram the HVAC control module with the updated software calibration using SPS. This new service calibration is available on TIS2WEB.
It is recommended that the HVAC actuators be recalibrated after the HVAC control module software is updated. Refer to Actuator Recalibration in the HVAC Control Module Programing and Setup section of SI for more information. When completed, the command state for the actuators will change from "None" to "On".
Warranty Information
For vehicles repaired under warranty, use the table above.
Disclaimer