PRE-RELEASE
DTC B2470
| DTC B2470 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptor |
DTC B2470 02
Cellular Phone Antenna Circuit Malfunction Short to Ground
DTC B2470 04
Cellular Phone Antenna Circuit Malfunction Open Circuit
| 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 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 signal splitter to power the internal navigation radio signal amplifier.
| Conditions for Running the DTC |
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Ignition in the RUN or ACC position.
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System voltage is between 9.5 V and 15.5 V.
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The above conditions are present for greater than 1 second.
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| Conditions for Setting the DTC |
The telematics communication interface control module does not detect the presence of a cellular phone antenna.
| Action Taken When the DTC Sets |
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The vehicle is unable to connect to the OnStar® Call Center.
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The OnStar® status LED turns red.
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| Conditions for Clearing the DTC |
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The telematics communication interface control module detects the presence of a cellular phone antenna.
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A history DTC clears after 50 malfunction-free ignition cycles.
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| Reference Information |
Schematic Reference
OnStar Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
OnStar Description and Operation
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
Special Tools
EL-49903 GM OnStar Antenna Diagnostic Tool Kit
| Circuit/System Verification |
Verify that the T4G cellular phone, navigation, and digital radio antenna assembly is not damaged.
| Circuit/System Testing (without Navigation Radio) |
| Note | ||
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The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax. |
| 1. |
Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 telematics communication interface control module.
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| 2. |
Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 to the K73 telematics communication interface control module.
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| 3. |
Clear the DTCs and operate the vehicle within the conditions for running the DTC. Verify DTC B2470 does not set.
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| 4. |
If the DTC sets, replace the K73 telematics communication interface control module.
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| 5. |
Ignition OFF, disconnect the EL-49903 from the K73 telematics communication interface control module and perform the coax cable test on the coax cable between the k73 telematics communication interface control module and the T4G cellular phone, navigation, and digital radio antenna.
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| 6. |
If the coax cable does not pass the test, replace the coax cable.
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| 7. |
If all circuits test normal, replace the T4G cellular phone, navigation, and digital radio antenna.
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| Circuit/System Testing (with Navigation Radio) |
| Note | ||
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The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax. |
| 1. |
Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 telematics communication interface control module.
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| 2. |
Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 to the K73 telematics communication interface control module.
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| 3. |
Clear the DTCs and operate the vehicle within the conditions for running the DTC. Verify DTC B2470 does not set.
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If the DTC sets, replace the K73 telematics communication interface control module.
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| 5. |
Ignition OFF, reconnect the coax cable to the K73 telematics communication interface module. Disconnect the coax cable from the T15 navigation signal splitter.
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Ignition ON, test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
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If not within the specified range, replace the coax cable.
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Ignition OFF, reconnect the coax cable to the T15 navigation signal splitter. Disconnect the coax cable from the T4G cellular phone, navigation and digital radio antenna.
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Ignition ON, test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
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| 10. |
If within the specified range, replace the T4G cellular phone, navigation and digital radio antenna.
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| 11. |
Ignition OFF, perform the coax cable test on the coax cable between the T15 navigation signal splitter and the T4G cellular phone, navigation and digital radio antenna, refer to Component Testing. The coax cable should pass the test.
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| 12. |
If the coax cable does not pass the test, replace the coax cable.
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If the coax cable passes the test, replace the T15 navigation and signal splitter.
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| Component Testing |
Refer to Test Probe Caution
| Note | ||
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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. |
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To prevent false reading 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.
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| 2. |
Test for less than 5 Ω between both ends of the coax cables center terminals.
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If greater than the specified range, replace the failed coax cable.
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| 4. |
Test for greater than 10k Ω between the coax cable center wire and the outer coax shield.
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| 5. |
If less than the specified range, replace the coax cable.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Navigation Signal Splitter Replacement
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Radio Antenna Base Replacement
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Control Module References
for telematics communication interface control module replacement, setup, and programming
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