Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DBβ LIVE
HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISENGINE PERFORMANCEREMOVE, OVERHAUL & INSTALLENGINE CONTROLS - REMOVAL & INSTALLATIONPROGRAMMINGPOWERTRAIN CONTROL MODULE (4.2L)REMOTE PROGRAMMING
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Remote Programming
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Remote Programming
NOTE:
DO NOT program a control module unless you are directed by a service procedure or you are directed by a technical service bulletin. Programming a control module at any other time will not permanently correct a customer's concern.
Remote Programming
- Connect Tech 2β’ scan tool to vehicle and obtain the module information using the following procedures:NOTE: Ensure control module is installed in vehicle and battery is fully charged before programming.
- Ensure engine and Tech 2β’ is off. Connect Tech 2β’ to Data Link Connector (DLC).
- Turn ON the Tech 2β’.
- Press ENTER at the title screen.
- Turn ignition on, with engine off.
- Select Service Programming System at the Main Menu.
- Select Request Info.
- Enter vehicle description by following the on-screen instructions.
- Turn OFF all accessories and select CONTINUE.
- Verify that the correct VIN is entered on the Tech 2β’ and select YES.
NOTE: Select Request Info Again if a Vehicle Identification Number (VIN) was previously stored in scan tool.NOTE: Select No and write down the VIN if the VIN is incorrect. - Turn off the Tech 2β’ scan tool.
- Disconnect Tech 2β’ from vehicle.
- Turn ignition off.
- Transfer the data from the terminal to the Tech 2β’ using the following procedure:
- Connect the Tech 2β’ to the terminal.
- Launch the TIS application at the terminal.
- Select the Service Programming System at the main screen.
- Highlight the following information on the Select Diagnostic Tool and Programming Process Screen:
- Select Diagnostic Tool. Select Tech 2β’.
- Select Programming Process. Identify whether an existing module is being reprogrammed or a module is being replaced with a new one.
- Select ECU Location. Select vehicle.
- Select NEXT.
- Verify the connections and select NEXT.
- Verify the VIN and select NEXT.
- Select the appropriate controller for the vehicle being serviced.
- Select the type of programming to be performed from the following categories:
- Normal. Used for updating an existing calibration or programming a new controller.
- Vehicle Configuration Index (VCI). Used for updating an existing controller or programming a new controller for newer vehicles whose VINs are not yet in the database.
- Reconfigure. Used to reconfigure a vehicle for changes in tire size and axle ratios.
- Select Next.
- Select the appropriate calibration file for the vehicle being serviced.
- Select NEXT.
- Verify your selection on the Summary screen.
- Select NEXT.
NOTE: The TIS supports service programming with the Tech 2β’ scan tool only.NOTE: You may receive a message stating that the control module could be a service control module if you selected NO to the VIN being correct. Click OK.NOTE: When selecting the Vehicle Configuration Index (VCI) programming type, a valid VCI number for the vehicle must be entered. This number may be obtained from the Techline Customer Support.NOTE: Refer to service bulletins before service programming is performed if the bulletins are listed along with the calibration files.NOTE: Select Cancel if you receive a message stating that the calibration selected is already the current calibration in the control module and reprogramming with the same download is not allowed. - Perform the Crankshaft Position Variation Relearn Procedure using the Special Functions feature, if applicable.
- Close the application and return to the TIS application Selection screen after the download is complete.
- Turn OFF the Tech 2β’.
- Disconnect Tech 2β’ from the terminal.
- Transfer the data from the Tech 2β’ to the control module using the following procedure:
- Connect the Tech 2β’ to DLC, with engine and Tech 2β’ OFF.
- Turn ON the Tech 2β’.
- Press ENTER at the title screen.
- Turn ignition on, with engine off.
- Select Service Programming System.
- Select the Program ECU function on the Tech 2β’.
- Verify the VIN and calibration numbers, select CONTINUE.
- Follow the on-screen instructions and select CONTINUE.
- Select continue and exit the program after the Tech 2β’ displays Programming Was Successful.
- Turn ignition off.
- Turn OFF the Tech 2β’.
- Disconnect the Tech 2β’ from the vehicle.
Programming Verification
- Turn ignition off for 30 seconds.
- Start engine.
NOTE:
Some vehicles will require that Idle Learn, TP Learn, Theft Deterrent Relearn or Crankshaft Variation Learn procedures be performed after programming.
NOTE:
Repeat the SPS procedure if vehicle does not start or starts but runs rough.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.