On-Board Diagnostic System Software Upgrade-Reprogram Engine Control Module (ECM)

This bulletin provides information about installing new Engine Control Module (ECM) software and calibration on certain 2005 Chevrolet Aveo model vehicles, equipped with a 1.6 liter 4 cylinder (RPO L91 - VIN 6) engine. The revised calibration includes several OBD system improvements that 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/80,000 mile 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 data version 4.0 or later, with Application 5.2, broadcast to dealers on April 5, 2005; and on TIS CD-ROM version 4.0 / 2005, or later, mailed to dealers beginning April 18, 2005.

The "Required Field Actions’ section of the GM Vehicle Inquiry System (GMVIS) must be checked to determine if a specific vehicle requires this action. If GMVIS indicates that this System Software Update Upgrade 05517 remains ‘open’ and ECM reprogramming has not taken place otherwise after the TIS Broadcast or CD-ROM availability dates identified in this bulletin, reprogram the ECM using a Tech 2 scan tool with the calibration update from Techline Information System (TIS) 2000.

ECM Reprogramming for J1979 Serial Communication Improvement

Notice: Before reprogramming, please check the battery condition to prevent a reprogram error of the ECM due to battery discharge. Battery voltage must be between 12 and 16 volts during reprogramming. If the vehicle battery is not fully charged, use jumper cables from an additional battery. Be sure to turn off or disable any system that may put a load on the battery such as automatic headlamps, daytime running lights, interior lights, heating, ventilation, and air conditioning (HVAC) system, radio, engine cooling fan, etc. A programming failure or control module damage may occur if battery voltage guidelines are not observed.

The ignition switch must be in the proper position. The Tech 2 prompts you to turn ON the ignition, with the engine OFF. DO NOT change the position of the ignition switch during the programming procedure, unless instructed to do so.

Make certain all tool connections are secure, including the following components and circuits:

DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming failure or control module damage may occur.

DO NOT turn OFF the ignition if the programming procedure is interrupted or unsuccessful. Ensure that all control module and DLC connections are secure and the TIS terminal operating software is up to date. Attempt to reprogram the control module. If the control module cannot be programmed, replace the control module.

Use the Technical Information System (TIS) Service Programming System (SPS) to program the J1979 serial communication improvement values into the ECM, using GM NAO TIS Data Version 4.0 for 2005, or later, with Application 5.2; or NAO CD 4, or later.

Tech 2 Remote Programming

1. Use normal "request method" through "Service Programming System" to request information from vehicle.
2. At Techline Terminal enter TIS SIPS programming system.
3. Select Tech 2 from the "Select Diagnostic Tool" window.
4. Select Reprogram ECU from the "Select Programming Process" window.
5. Select Vehicle from the "Select ECU Location: window.
6. Select Next to go to the "Preparing for Communication" instruction Screen.
7. Select Next to verify vehicle identification number (VIN).
8. Select Next to view the "Select Programming Type" window.
9. Select Normal from the "Select Programming Type" window.
10. Select Next to view "Summary" screen.
11. Verify that the following information is displayed on the "Summary" screen: Your Part Number must begin with 96499746.XIAM (manual transmission) or 96499747.XAIL (automatic transmission) "J1979 Serial Communication Improvement."
12. Select Next to download the "J1979 Serial Communication Improvement" values to new software and calibration into the Tech 2.
13. Back at the vehicle enter "Service Programming Systems."
14. Select "Program ECU" and follow on screen instructions.
15. Make sure to turn OFF the ignition for 30 seconds after the "Programming is Complete" screen is displayed. Clear diagnostic trouble codes (DTCs), if required.

Important: After reprogramming the ECM, start the engine and let it run for a few minutes to warm up. When the engine has reached normal operating temperature, perform the "CKP System Variation Learn" procedure in this bulletin.

CKP System Variation Learn Procedure

Important: If the crankshaft position variation learn procedure has not learned, a false misfire could be detected and DTC P0300 may set. If sent here from DTC P0300, proceed with the crankshaft position variation learn procedure.

1. Monitor the engine control module (ECM) for DTCs with a scan tool. If other DTCs are set, except DTC P0300, or P0315, refer to "Diagnostic Trouble Code (DTC) List," SI document 1551632 for the applicable DTC.
2. Select the crankshaft position variation learn procedure with a scan tool.
3. The scan tool instructs you to perform the following:

3.1.	Block drive wheels.

3.2.	Accelerate to wide open throttle (WOT).

3.3.	Release throttle when fuel cut-off occurs.

3.4.	Observe fuel cut-off for applicable engine.

3.5.	Engine should not accelerate beyond calibrated RPM value.

3.6.	Release throttle immediately if value is exceeded.

3.7.	Set parking brake.

3.8.	DO NOT apply brake pedal.

Important: The scan tool will lose communication momentarily when the ignition is cycled from OFF to ON. Press ENTER when the scan tool displays the screen again.

3.9.	Cycle ignition from OFF to ON.

3.10.

Apply and hold brake pedal.

3.11.

Start and idle engine.

3.12.

Turn A/C OFF. Vehicle must remain in Park or Neutral. The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components:

•	Crankshaft position (CKP) sensors activity: If there is a CKP sensor condition, refer to the applicable DTC.

•	Camshaft position (CMP) signal activity: If there is a CMP signal condition, refer to the applicable DTC.

•	Engine coolant temperature (ECT): If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.

4. Enable the CKP system variation learn procedure with the scan tool and perform the following:

Important: While the CKP variation learn procedure is in progress, hold the throttle at WOT for 5 fuel-cutoffs. The learn procedure must determine there has been 5 fuel-cutoffs to properly perform the test.

•	Accelerate to WOT.

•	Hold throttle while fuel cut-off occurs.

5. The scan tool displays Learn Status: Learned this ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTCP0315 failed or did not run, refer to "DTC P0315," SI document 1458104. If any other DTCs set, refer to "Diagnostic Trouble Code (DTC) List," SI document 1551632 for the applicable DTC.
6. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully

6. . The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether or not DTC P0315 is set:

For vehicles repaired under the 8 year/80,000 mile emission controller warranty use: