Description On-Board Diagnostics - OnStar System
Self-diagnostic FunctionThe OnStar control unit has a self-diagnostic function.
Entering the self-diagnostic function
Before doing the self-diagnostic function, check the No. 5 (7.5 A) fuse, the No. 21 (10 A) fuse and the No. 32 (10 A) fuse in the driver's under-dash fuse/relay box.
1. Turn the ignition switch OFF.
2. Press and hold the call answer/call end (white phone) button, and turn the ignition switch from off (0) to ACC (I) three times within 6 seconds ending with the ignition switch in ACC (I).
3. The indicator will flash (green or red) if any failures have been detected. Troubleshoot the DTCs as indicated below.
NOTE:
- When the OnStar system enters the self-diagnostic mode, if the OnStar system has current DTCs, OnStar system will flash the red LED to display current DTCs.
- If the OnStar system has only history DTCs, then the OnStar system will flash the green LED to display history DTCs.
- When the ignition switch is turned OFF after 3 seconds of DTC display, the OnStar system will exit the self-diagnosis mode and turn OFF.
- When there is no operation after DTC display, then OnStar system will exit self-diagnosis mode.
Output Mode
When the ignition switch is turned OFF within 3 seconds after DTC display, the OnStar system will enter the output mode. When all operations have been completed, the OnStar system will exit the self-diagnosis mode and turn OFF.
Display Emergency and Collision Log Mode
When the emergency button is pressed and held for 5 seconds or longer (within 3 seconds after the last DTC is indicated) after DTC display, the OnStar system will enter the display emergency log mode and flash the red LED the number of times stored in the collision call log (Black-box), and flash the green LED the number of times stored in the emergency log (Black-box). The LED flash will be the same way for the display of the second digit DTC. The OnStar system will repeat the LED flash of the emergency and collision log twice, then the OnStar system will exit the self-diagnostic mode.
Delete DTC Mode
The OnStar system will delete all the DTCs when the OnStar button is pressed (for less than 2 seconds) within 3 seconds after the DTCs are finished being displayed. The system will then exit the DTC delete mode and enter the self-diagnostic mode.
NOTE: The DTCs must be cleared manually to remove all history DTCs.