How to Display The DTC
When the OnStar control unit enters the diagnosis mode, and has current DTCs, the OnStar control unit will flash the OnStar LED indicator RED to display current DTCs. If the OnStar control unit has only history DTCs, the OnStar control unit will flash the OnStar LED indicator GREEN to display history DTCs.
NOTE:
If the OnStar LED is solid RED and you cannot pull DTC's because the buttons are non-responsive, do the DTC 2-5 troubleshooting first.
DTC INDEX
| First Digit | Second Digit | Detection Items |
|---|---|---|
| 1 | 1 | OnStar control unit failure (DSO error, CFU or DSP memory error) (see DTC 1-1: ONSTAR CONTROL UNIT INTERNAL ERROR (DSP COMMUNICATE ERROR, CPU OR DSP MEMORY ERROR) ) |
| 1 | 2 | EEPROM failure (see DTC 1-2: ONSTAR CONTROL UNIT INTERNAL ERROR (EEPROM ERROR) ) |
| 1 | 3 | GPS receiver failure (see DTC 1-3: GPS RECEIVER ERROR ) |
| 1 | 4 | Phone module failure (see DTC 1-4: TELEPHONE MODULE ERROR ) |
| 2 | 1 | Collision detection signal failure (see DTC 2-1: ONSTAR CONTROL UNIT LOST COMMUNICATION WITH SRS UNIT (COLLISION DETECTION SIGNAL ERROR) ) |
| 2 | 3 | GPS antenna failure (see DTC 2-3: GPS ANTENNA CIRCUIT MALFUNCTION ) |
| 2 | 4 | Phone antenna failure (see DTC 2-4: CELLULAR PHONE ANTENNA CIRCUIT MALFUNCTION ) |
| 2 | 5 | Four button failure (see DTC 2-5: ONSTAR SWITCHES (FOUR BUTTONS) CIRCUIT MALFUNCTION ) |
| 2 | 6 | Microphone failure (see DTC 2-6: MICROPHONE CIRCUIT MALFUNCTION ) |