Communication Interface Module

DTC B2462 (Communication Interface Module)

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 B2462 02
- Global Positioning System (GPS) Signal Short to Ground

DTC B2462 04
- Global Positioning System (GPS) Signal Open Circuit

Circuit/System Description

The communication interface module (CIM) receives information from a specific GPS antenna located on the outside of the vehicle. The GPS antenna is connected to the CIM via a shielded coaxial cable. The antenna cable also provides a path for DC current for powering the antenna.

Conditions for Running the DTC

* Ignition is in the RUN or ACC position.
* Battery voltage is between 9-16 V.

Conditions for Setting the DTC

B2462 02

The CIM detects a short to ground on the GPS antenna signal circuit.

B2462 04

The CIM detects an open/high resistance on the GPS antenna signal circuit.

Action Taken When the DTC Sets

* The OnStar(R) status LED turns red.
* The OnStar(R) Call Center cannot locate the vehicle.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

OnStar Schematics (OnStar Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

OnStar Description and Operation (OnStar Description and Operation)
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

Programming and Relearning (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Disconnect the GPS antenna coax cable from the CIM. Refer to Antenna Coaxial/Connector Cable Identification Table (Application and ID).
2. Ignition ON, test for 4.5-5.5 V between the CIM coax cable center conductor terminal at the module and ground.

• If not within the specified range, replace the CIM.

3. Reconnect the coax cable to the CIM. Disconnect the coax cable from the GPS antenna.
4. Test for 4.5-5.5 V between the coax cable center conductor and the outer shield.

• If not within the specified range, replace the coax cable.

5. If all circuits test normal, replace the GPS antenna.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Radio Antenna Base Replacement (Radio Antenna Base Replacement)
* Control Module References (Programming and Relearning) for CIM replacement, setup, and programming