B2470
DTC B2470
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B2470 02
- Cellular Phone Antenna Circuit Malfunction Short to Ground
DTC B2470 04
- Cellular Phone Antenna Circuit Malfunction Open Circuit
Diagnostic Fault Information
Circuit/System Description
The cellular phone and navigation antenna is connected to the telematics communication interface control module. This module supplies 5 V to the cellular phone and navigation antenna to power the internal amplifier. When the vehicle is equipped with the optional navigation radio, a navigation antenna signal splitter is installed to distribute the GPS signal to both the telematics communication interface control module and the navigation radio. The navigation radio supplies 5 V through the GPS antenna coaxial cable to the navigation antenna signal splitter to power the internal navigation radio signal amplifier.
Conditions for Running the DTC
* Ignition in the RUN or ACC position.
* System voltage is between 9.5 volts and 15.5 volts.
* The above conditions are present for greater than 1 s.
Conditions for Setting the DTC
* The telematics communication interface control module does not detect the presence of a cellular antenna.
* The above conditions are present for greater than 1 s.
Action Taken When the DTC Sets
* The vehicle is unable to connect to the OnStar(R) Call Center.
* The OnStar(R) status LED turns red.
Conditions for Clearing the DTC
* The telematics communication interface control module detects the presence of a cellular antenna.
* A history DTC clears after 50 malfunction-free ignition cycles.
Reference Information
Schematic Reference
OnStar Schematics OnStar Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left
Description and Operation
OnStar Description and Operation OnStar
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
EL-49903 - GM OnStar Antenna Diagnostic Tool Kit
Circuit/System Testing
Note:
* The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.
* The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 minutes after turning the ignition ON for the GPS satellites to acquire vehicle signal.
Without Navigation Radio
1. Ignition OFF and all vehicle systems OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 min for all vehicle systems to power down.
2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 - GM OnStar antenna diagnostic tool kit to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON.
3. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
• If the DTC sets
Replace the K73 Telematics Communications Interface Control Module.
• If the DTC does not set
4. Ignition OFF.
5. Disconnect the EL-49903 - GM OnStar antenna diagnostic tool kit from the K73 Telematics Communication Interface Control Module
6. Test the coax cable. Refer to Component Testing.
• If the coax cable does not pass the test
Replace the coax cable.
• If the coax cable passes the test
7. Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.
With Navigation Radio
1. Ignition OFF and all vehicle systems OFF, disconnect the GPS and cellular coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 min for all vehicle systems to power down.
2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 - GM OnStar antenna diagnostic tool kit to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON.
3. Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
• If the DTC sets
Replace the K73 Telematics Communication Interface Control Module.
• If the DTC does not set
4. Ignition OFF.
5. Disconnect the EL-49903 - GM OnStar antenna diagnostic tool kit from the K73 Telematics Communication Interface Control Module
6. Connect the coax cable to the K73 Telematics Communications Interface Control Module and disconnect the coax cable from the T15 Navigation Antenna Signal Splitter, ignition ON.
7. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
• If less than 4.5 V
1. Ignition OFF.
2. Test the coax cable. Refer to Component Testing.
• If the coax cable does not pass the test, replace the coax cable.
• If the coax cable passes the test, test or replace the K73 Telematics Communications Interface Control Module.
• If greater than 5.5 V
1. Ignition OFF.
2. Test the coax cable. Refer to Component Testing.
• If the coax cable does not pass the test, replace the coax cable.
• If the coax cable passes the test, test or replace the K73 Telematics Communications Interface Control Module.
• If between 4.5-5.5 V
8. Ignition OFF, connect the coax cable to the T15 Navigation Antenna Signal Splitter and disconnect the coax cable from the T4G Cellular Phone, Navigation, and Digital Radio Antenna, ignition ON.
9. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
• If less than 4.5 V
1. Ignition OFF.
2. Test the coax cable. Refer to Component Testing.
• If the coax cable does not pass the test, replace the coax cable.
• If the coax cable passes the test, test or replace the T15 Navigation Antenna Signal Splitter.
• If greater than 5.5 V
1. Ignition OFF.
2. Test the coax cable. Refer to Component Testing.
• If the coax cable does not pass the test, replace the coax cable.
• If the coax cable passes the test, test or replace the T15 Navigation Antenna Signal Splitter.
• If between 4.5-5.5 V
10. Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.
Component Testing
Caution: Refer to Test Probe Caution Test Probe Caution
Note:
* Before testing the coax cable, check the cable exterior for being pinched, cut, damaged, or having loose connections at the components, which can cause reception issues.
* To prevent false readings when testing the center coax terminals, use care not to ground the test probe on the outer housing/shield.
Coax Cable Test
1. Ignition OFF, disconnect the coax cable at both components.
2. Test for less than 5 ohms between the coax cable center terminal end to end.
• If 5 ohms or greater
Replace the coax cable.
• If less than 5 ohms
3. Test for greater than 5 ohms between the coax cable outer shield end to end.
• If 5 ohms or greater
Replace the coax cable.
• If less than 5 ohms
4. Test for infinite resistance between the coax cable center terminal and the coax cable outer shield.
• If less than infinite resistance
Replace the coax cable.
• If infinite resistance
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Navigation Signal Splitter Replacement Service and Repair
* Radio Antenna Base Replacement Radio Antenna Base Replacement
* Control Module References Control Module References for Telematics Communication Interface Control Module replacement, programming and setup.