OnStar(R) - Telematics Indicator Is Red
91 08 712010199/3
November 7, 2008.
Supersedes Technical Service Bulletin Group 91 number 07-25 dated June 20, 2007 for reasons listed below.
Affected Vehicles
91 Telematics by OnStar switch assembly indicator light is red
Condition
Indicator light in the Telematics switch assembly is red. Telematics system is functional.
May be caused by DTC 01531 (Signal too low or value below lower control limit) for the Telematics emergency battery having been stored in the Telematics Control Module DTC memory.
Technical Background
If ignition is switched on for 30 seconds or more, the Telematics system enters into the emergency battery get ready mode.
If, after this time frame, the Telematics control module detects a sudden drop in vehicle system voltage (for example, engine starting phase) below 8.3 volts even for a millisecond, the Telematics control module will activate the emergency battery. Activating the emergency battery takes 1 minute away from the timer.
If this event takes place five times, regardless of time between events (days, weeks, or months), DTC 01531 is stored. Specification for the emergency battery is 5 minutes.
Tip:
In most cases, the emergency battery voltage is sufficient to provide power to the Telematics control module if the vehicle power supply is interrupted.
Production Solution
Not applicable.
Service
1. Check Telematics emergency battery voltage to determine if replacement is necessary.
2. Install a DC / DC converter kit, Part No: 4B0998 099C. Kit consists of a DC / DC converter, jumper harness, and Velcro tape.
Telematics emergency battery, checking voltage
1. Connect VAS 5051/5052 diagnostic tool.
2. Switch ignition on.
3. From Start-up screen, select Vehicle Self Diagnosis >> 75 - Telematics >> 08 - Read measuring valueblock >> Display group 30.
4. Check value in channel 4.
- If reading is 19.0 volts or higher, emergency battery is OK.
- If less than 19.0 volts, emergency battery requires replacement.
5. In either case, switch Telematics emergency battery off.
a. Select the arrow on navigation bar.
b. Select Select diagnosis function >> 10 - Adaptation >> Channel 8 >> Q.
c. Enter and store value 02 to switch emergency battery off.
d. Return to Start-up screen. Select Vehicle Self-Diagnosis.
e. Switch ignition off.
Telematics Control Module and emergency battery, accessing
1. Remove glove box. (See Repair Manual >> Body Interior >> Group 68 - Storage compartments, covers and trim parts >> Glovebox, removing and installing).
2. Access emergency battery. (See Repair Manual >> Electrical Equipment >> Communication Group 91 - Radio,Telephone, Navigation, Trip computer >> Telematics, Emergency battery, removing and installing.)
3. Remove Telematics control module (Figure 1, Point 1) from mounting bracket.
1. Disconnect electrical and antenna connecters from the Telematics control module.
2. If emergency battery voltage was less than 19.0 volts in previous test, the emergency battery (Figure 1, Point 3) requires replacement. Remove from housing (Figure 1, Point 2) and install new battery.
DC/DC converter, installing
Figure 2:
1. Using Velcro from kit, attach the DC / DC converter (Figure 2, white arrow) to the side of Telematics control module as shown.
2. Re-connect antenna cables to Telematics control module.
3. Connect Blue vehicle harness electrical connector (Figure 2, 2) to the blue connector of the DC/ DC converter (Figure 2, white arrow).
4. Connect black connector (Figure 2, 1) of the jumper harness to the black connector of the DC/DC converter (Figure 2, white arrow).
5. Route jumper harness as shown (Figure 2, black arrow) and connect the blue connector of the jumper harness to the blue connector of the Telematics control module.
6. Reinstall Telematics control module to mounting bracket.
7. Reinstall carpeting and vehicle trim.
8. Reinstall glove box.
9. Using VAS scan tool:
a. Switch ignition on.
b. Return to "Select diagnosis function" screen using arrow on navigation bar.
c. Select 10 - Adaptation >> channel 8 >> Q.
d. Enter and store value 01 to switch emergency battery on and reset timer.
Tip:
The timer must be reset even if an old battery is reused.
e. Check for system stored DTCs. (Erase as necessary.)
f. Verify indicator light in Telematics switch assembly is green.
g. Test function of OnStar by Telematics.
Warranty
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.