GM Service Manual Online
For 1990-2009 cars only

Flash Code Diagnostics

The cruise control module (CCM) has diagnostic capabilities. When the CCM is placed in diagnostic mode, it will display flash codes using the CRUISE indicator lamp in the instrument cluster. The diagnostic mode can be established by using a scan tool or by grounding a cavity in the DLC.

Displaying Flash Codes using the Scan Tool

Install a scan tool and turn ON the ignition with the engine OFF. Locate the Body section in the scan tool, select cruise, and enable the diagnostics. This action pulls the cruise control module (CCM) terminal 10 to ground and signals the CCM to enter the FLASH DTC diagnostic display mode.

Displaying Flash Codes using a Jumper Wire.

Connect a jumper between cavity 4 and cavity 13 with the ignition ON, and the engine OFF. This action pulls the cruise control module (CCM) terminal 10 to ground and signals the CCM to enter the FLASH DTC diagnostic display mode.

How to read the Flash Codes

The CCM displays the DTCs by flashing the cruise control indicator lamp. Each DTC that is displayed consists of the following:

    • A series of flashes which represent the tens (first) DTC digit
    • A 2.5 second pause
    • A series of flashes which represent the ones (second) DTC digit

For example, a FLASH DTC of 32 would be displayed as: three flashes, a 2.5 second pause, and two more flashes. Each DTC is flashed once before moving on to the next DTC. After all the DTCs are displayed, the entire DTC sequence is continually repeated until you remove the jumper from the DLC.

If there are no DTCs present, the CCM will flash the CRUISE indicator lamp continuously. This indicates that FLASH DTC diagnostics have been enabled. The CCM will continue to flash the Cruise indicator lamp until you exit from the scan tool selection or the jumper wire is removed from the DLC.