On-Board Diagnostic System Software Upgrade-OBD O2 Sensor System Improvements-Reprogram Engine Control Module (ECM)

THIS BULLETIN IS BEING REVISED TO UPDATE THE SOFTWARE CALIBRATION PART NUMBER INFORMATION. PLEASE DISCARD ALL COPIES OF 05567.

This bulletin provides information about installing new Engine Control Module (ECM) software and calibration on certain 2004-05 Chevrolet Epica model vehicles, equipped with a 2.5L L6 (VIN L - RPO LBK) engine. The revised calibration includes OBD system improvements to correct vehicles experiencing a high level of unintentional illumination of the Malfunction Indicator Lamp (MIL), or false MIL, for the front and rear oxygen sensor response diagnostics as well as the evaporative emission system leak diagnostics, and should be installed as soon as practical. Install the new calibration on all affected vehicles identified in this bulletin, including vehicles in new dealer inventory and any vehicles that return for service, for any reason, during the applicable 8 year / 130,000 km emission controller warranty coverage period. To verify if an updated calibration is required, refer to the following procedure in this bulletin.

Important: Do not attempt to order the calibration number from GMSPO. The calibration numbers are programmed into the ECM via a Techline Tech 2 scan tool and the Techline Information System (TIS) 2000 terminal with the calibration update. Use TIS data version 1.00 or later, broadcast to dealers via GM Access on January 5, 2006, and on the latest TIS 2000 CD-ROM version #1.35/2006, available after January 23, 2006.

Important: Before programming a control module, ensure that:

1. Connect the Tech 2® scan tool to the vehicle.
2. Request vehicle information using the Tech 2®.
3. Disconnect the Tech 2® from the vehicle and connect it to a TIS 2000 terminal.
4. Select Service Programming System.
5. Select Tech 2® remote programming.
6. TIS 2000 will recognize the VIN and request country usage.
7. TIS 2000 will show the current calibration on the Tech 2® and what is available to reflash on TIS 2000.
8. Select Reprogram.
9. When upload of selected calibration is complete, disconnect the Tech 2® and return to the vehicle.
10. Connect the Tech 2® to the vehicle and go to the Service Programming System menu.
11. Select Program ECU and follow the instructions. The download process to the vehicle’s ECM may take up to 10 minutes.
12. When the Tech 2® display indicates "Download Completed Successfully," turn the ignition key OFF for 60 seconds.
13. Turn ignition key ON and clear any engine or transmission DTCs that are set.
14. Reset the following ECM settings using the Tech 2® scan tool: ISC System and ECM.
15. Stabilize idle speed with the following procedure (refer to Idle Learn Procedure [SI Document ID 1686318]):

•	Ignition key OFF for 10 seconds

•	Ignition key ON for 10 seconds

•	Ignition key OFF for 10 seconds

16. Start the vehicle and confirm that the Check Engine Light/Malfunction Indicator Lamp is off.

For vehicles repaired under the 8 year / 130,000 km emission controller warranty use: