Automatic Climate Control Overcompensation (Verify Automatic Climate Control Functions and Review Customer Information)

Some customers may comment on one or more of the following conditions:

1. Automatic climate control system may not maintain desired temperature setting or may overcompensate (overshoot) desired temperature.
2. Blower may move high volume of air shortly after vehicle start-up when automatic climate control system is in the "Auto" mode.
3. Temperature of air from vents may be hotter or colder than selected temperature.

The conditions listed above may be caused by the software calibration in the automatic climate control module. Customers may also be unfamiliar with operating characteristics of the automatic climate control system.

1. Verify that there is air flow through the inside temperature sensor in the control module.

1.1.	Turn the ignition ON, with the engine OFF.

1.2.	Set the MODE to panel vent mode.

1.3.	Turn blower motor (fan speed) to maximum speed position.

1.4.	Place a small piece of paper (25 mm x 25 mm [1 in x 1 in]) in front of the aspirator tube opening.

-	If paper stays in place, the aspirator tube and inside air temperature sensor has proper air flow.

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If paper does not stay in place, the aspirator tube may be leaking or blocked. Inspect the aspirator tube for an air leak, poor connection, or obstruction, and repair if necessary. Refer to "Aspirator Hose - Automatic Climate Control Removal and Installation" procedure in the 2002-2003 Saturn L-Series HVAC Service Manual, Vol. I. (SI Document ID #899158 [for 2002 model year vehicles] and 1246355 [for 2003 model year vehicles]) or "Aspirator Replacement" procedure in the HVAC section of the 2004 Saturn L-Series Service Manual, Vol. 1 (SI Document ID #1246355).

2. Inspect passenger compartment air filter. If filter is dirty or obstructed, replace filter. Refer to "Passenger Compartment Air Filter Removal and Installation" procedure in the 2002-2003 Saturn L-Series HVAC Service Manual, Vol. I. (SI Document ID #899169 [for 2002 model year vehicles] and 977355 [for 2003 model year vehicles]). The procedures for passenger compartment air filter replacement in SI and the printed Service Manuals also apply to 2004 model year vehicles.
3. Verify that automatic climate control module calibration version is 7.2 or greater (P/N 22718824 or greater). Refer to "Checking Calibration Part Number" in the Service Procedure section of this bulletin for instructions for checking calibration version.

•	If calibration is not P/N 22718824 or greater, install latest available calibration. Refer to "Installing New Calibration" in the Service Procedure section of this bulletin.

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If calibration is current, P/N 22718824 or greater, review and emphasize automatic climate control system operating characteristics with customer. Many customer concerns relate to normal operating characteristics of the automatic climate control system. Refer to the Customer Information section of this bulletin.

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If other issues that do not appear to be normal operating characteristics are present, refer to the "Automatic Climate Control Diagnostics" section in the 2002-2003 Saturn L-Series HVAC Service Manual, Vol. I or the "HVAC Systems - Automatic: Diagnostic Information and Procedures" subsection in the HVAC section of the 2004 Saturn L-Series Service Manual, Vol. 1 for additional diagnostic information.

-	If no other issues are present, then no further service is required. In these cases, performing vehicle service based on customer feedback regarding system performance will provide no operational benefits.

Checking Calibration Part Number

Important: You must view calibration numbers using the TECH 2 Scan Tool and NOT the Saturn Service Stall System (SSS).

1. Connect Tech 2 Scan Tool to the vehicle.
2. Navigate to the "Auto HVAC" Menu.
3. Select ID INFORMATION.
4. Read "End Model Part Number."

•	If calibration is not P/N 22718824 or greater, install latest available calibration. Refer to "Installing New Calibration" in the Service Procedure section of this bulletin.

•	If calibration is current, P/N 22718824 or greater, review and emphasize automatic climate control system operating characteristics with customer. Refer to the Customer Information section of this bulletin.

5. Disconnect Tech 2 Scan Tool from vehicle.

Installing New Calibration

Important: Saturn Service Stall System (SSS) software version 2.4, data release TIS 2.0 2003 (distributed February 2003) or greater is required in order to reprogram the automatic climate control module.

1. Install new calibration, P/N 22718824 or greater. Refer to "Service Programming System (SPS)" in the Saturn Service Stall System (SSS) User Guide for reprogramming procedures.
2. Verify HVAC functionality after reprogramming the automatic climate control system.

To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System for any of the following, depending on procedure performed:

If another procedure is performed, refer to the appropriate Electronic Labor Time Guide for the correct Labor Operation Code and Time.

Saturn L-Series Auto Climate Control System

Your Saturn L-Series vehicle is equipped with an Auto Climate Control System (ACCS). Electronic sensors measure temperatures inside and outside of the vehicle, and the system makes any necessary adjustments to airflow, fan speed, and air temperature. Initial setting is simple -- put the system in the automatic mode and select a comfortable temperature -- similar to the central heating and air conditioning systems found in most homes.

1. Press the "AUTO" switch to turn the ACCS on.
2. Turn the fan speed selector to "AUTO." The fan speed selector knob may also be used to manually control fan speed. Rotate the knob clockwise past the AUTO setting to increase fan speed. The fan speed will increase as the knob is turned clockwise. The temperature control will still be maintained automatically even when the fan speed is manually set. However, manually selecting high fan speeds for prolonged periods may cause the interior compartment temperature to overshoot the desired temperature.
3. Select the desired temperature using the temperature control knob. The selected temperature will appear in the digital display.
4. The "MODE" button may be used to manually control the air flow direction. The ACCS will automatically select the optimum air flow direction mode; however, if another air flow direction mode is desired, it can be selected using the MODE button. Pressing the MODE button once will display the current air flow direction. Pressing the MODE button repeatedly will display each of the different mode options. The temperature control will still be maintained automatically even when the air flow direction is manually set.

The ACCS will not function effectively if...

To make the most of your system...