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GM/Detroit 6.5L – TECH 1 “SCAN” TOOL – Powertrain Diagnostics

1. With the “Applications” screen visible (refer to figure 6-17), press the F0 key to enter powertrain diagnos­tics.

2. The next screen to display (figure 6-18) asks you to identify the vehicle model year. Do this by entering the vehicle model year’s last two digits. This information can be obtained from the vehicle identification number (VIN). It is the tenth character of the VIN. For instruc­ tions on identifying VIN codes, consult the General Information section of the Driveability and Emissions Sen/ice Manual.

3. After entering the model year, the Tech 1 screen prompts you for the vehicle PCM type, as shown in figure 6-19. You can identify the PCM type in one of three ways:
a. By entering the eight digit of the VIN code, which identifies engine type
b. By identifying the fuel delivery system of the vehicle
c. By selecting “diesel” from the selection screen (figure 6-19).

Identifying PCM by VIN engine code:
• Select VIN by pressing the FO key from the PCM identification screen shown in figure 6-19.
• The Tech 1 will display the screen shown in figure 6-20, asking you to enter the eighth digit of the vehicle’s VIN.

• Press the NO key to scroll through the choices until you arrive at the correct character.
• With the correct character high­ lighted, press the YES key to make the selection.

• The Tech 1 will prompt you to verify the PCM/engine type, as shown in figure 6-21. Press YES if correct.

Identifying PCM by fuel delivery system:
• From the PCM selection screen (see figure 6-19), press F1 to select PFI.
• Again, select the character corresponding to the eight character of the vehicle’s VIN (see figure 6-19). Use the NO key to scroll until the correct characters is highlighted, then press YES.
• The Tech 1 will display will ask you to verify the PCM according to type (figure 6-22).
Press YES is this is correct.

Identifying PCM by engine type:
• From the PCM selection screen (see figure 6-19), press F6 to select diesel. A confirma­tion screen (figure 6-23) will appear.

4. After identifying the PCM type, perform the On-Board Diagnostic (OBD) check, as described earlier in this section or in section 3 of the Service Manual.

The OBD verifies proper operation of the PCM’s self diagnostics. These on-board diagnostics must be op­erating properly for the PCM to accurately monitor vehicle systems and store Diagnostic Trouble Codes.
The OBD directs you to retrieve trouble codes and perform the appropriate diagnostics, or to compare Tech 1 data with the typical values for various system components. These, as well as other processes, are described on the following pages.


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