Cellular System, Entertainment System, and Navigation System: Diagnosis Chevrolet Silverado Classic 1500 HD

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Scan Tool Data List

Scan Tool Data List

Circuit Description

This DTC is set as current in all vehicle communication interface module (VCIM) service parts and has been implemented as a reminder to contact the OnStar® Call Center to properly update the customer's account once the new module has been installed. This call is initiated automatically after the installation of the replacement VCIM, and the completion of the Setup New VCIM procedure on the scan tool. No external circuits are involved.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC B1001 Option Configuration Error

Conditions for Running the DTC

The DTC is only run once per ignition cycle after a VCIM service part installation.

Conditions for Setting the DTC

This DTC is set as current in every VCIM service part, until the Setup New VCIM procedure on the scan tool has been performed after a service replacement.

Action Taken When the DTC Sets

1. The OnStar® status LED turns red.
2. The blue OnStar® Call Center button is disabled.

Conditions for Clearing the DTC

A current DTC clears following the successful completion of the Setup New VCIM procedure via the scan tool.

DTC B1001

When the radio is powered up, the radio supplies low level audio signals to the speakers. If the vehicle is equipped with an audio amplifier, the amplifier will boost the signal sent to the speakers. The radio tests the speaker output circuits for a short to voltage or ground.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC B1025 Audio Output 1 (Left Front) Circuit
2. DTC B1035 Audio Output 2 (Right Front) Circuit
3. DTC B1045 Audio Output 3 (Left Rear) Circuit
4. DTC B1055 Audio Output 4 (Right Rear) Circuit

The test is performed when the radio switches from OFF to ON. The radio will continue to test for the fault once every 0.5 seconds.

The radio sets a current status for this DTC when a short to ground or voltage is detected on any of the speaker channels for 1.5 seconds.

No sound is present from one or more of the speakers.

The condition is no longer present for 5 seconds.

The antenna enable/amplifier on signal is a class 2 signal sent from the radio through the rear seat audio (RSA) module, when equipped. The amplifier will reach full output capabilities 900 milliseconds after receiving this signal. The amplifier will then be capable of class 2 functions 60 milliseconds after being turned ON. This DTC will be set if the circuit is shorted to ground or battery.

This diagnostic procedure supports the following DTC

DTC B1235 Amplifier On Signal Circuit

This test is run at least every 50 milliseconds.

The failure must occur for at least 3 seconds.

The antenna enable/amplifier on signal circuit becomes disabled, causing the controlled module to become inoperative.

The failure criteria is no longer detected for 50 milliseconds.

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(ref-277883-S07139257572008012100000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-277883-S33769936482008012100000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-277883-S17347055992008012100000) provide an overview of each diagnostic category.

Diagnostic Fault Information

DTC B1259

This test is run every 300 milliseconds.

The digital radio receiver (DRR) detects an antenna fault.

The radio displays "No XM Signal" or "Check Antenna".

1. The condition must be corrected.
2. The DTC clears after 100 malfunction-free ignition cycles.

Circuit/System Testing

1. Ignition OFF, disconnect the antenna coax from the digital radio receiver (DRR). Connect the test antenna to the DRR.
2. Turn the ignition ON, radio ON tuned to XM. Verify that DTC B1259 is not current. If the DTC B1259 is still current, replace the DRR.
3. Ignition is OFF. Disconnect the DRR antenna from the coaxial cable. Test the resistance of the antenna coaxial cable center conductor from end to end. Verify the resistance is less than 5 ohms. If the resistance is greater than 5 ohms, replace the antenna coaxial cable.
4. Test the resistance of the antenna coaxial cable outer shield from end to end. Verify the resistance is less than 5 ohms. If the resistance is greater than 5 ohms, replace the antenna coaxial cable.
5. Test the resistance of the antenna coaxial cable between the center conductor and the outer conductor. Verify there is infinite resistance between both conductors. If there is less than infinite resistance between the inner conductor and the outer conductor of the coaxial cable, replace the antenna coaxial cable. If the coaxial cable tests normal, replace the digital radio antenna.

The vehicle communication interface module (VCIM) detects that the cellular microphone is connected through the cellular microphone signal circuit and the cellular microphone low reference circuit.

This diagnostic procedure supports the following DTC

DTC B2455 Cellular Phone Microphone Circuit Malfunction

1. The ignition must be in the RUN or ACC position.
2. The system voltage is at least 9.5 volts and no more than 15.5 volts.
3. All the above conditions are present for greater than 10 seconds.

1. The VCIM detects an open in the cellular microphone low reference circuit or a short to voltage in the cellular microphone signal circuit.
2. The above conditions are present for greater than 10 seconds.

1. The VCIM will not receive any signal from the microphone.
2. Calls can be placed but the caller cannot be heard.
3. The OnStar® status LED turns RED.

1. The VCIM detects the microphone connected for 5 consecutive 100 millisecond cycles.
2. A history DTC clears after 50 malfunction free ignition cycles.
3. The VCIM receives the clear DTC command from the scan tool.

The cellular antenna is connected to the vehicle communication interface module (VCIM) with a RG-58 coax cable. The VCIM polls the data from the cellular antenna once every second.

This diagnostic procedure supports the following DTC

DTC B2470 Cellular Phone Antenna Circuit Malfunction

1. The ignition must be in the RUN or ACC position.
2. The system voltage is at least 9.5 volts and no more than 15.5 volts.
3. All the above conditions are present for greater than 1 second.

1. The VCIM does not detect the presence of a cellular antenna.
2. All the above conditions are present for greater than 1 second.

1. The OnStar® status LED turns red.
2. The vehicle is unable to connect to the OnStar® Call Center.

1. The VCIM detects the presence of a cellular antenna.
2. A history DTC clears after 50 malfunction-free ignition cycles.
3. The VCIM receives the clear DTC command from the scan tool.

The OnStar® button assembly consists of 3 buttons, Call/Answer, OnStar® Call Center, and OnStar® Emergency. Ten volts are supplied to the button assembly on the keypad supply voltage circuit. Each of the buttons, when pressed, complete the circuit across a resister allowing a specific voltage to be returned to the vehicle communication interface module (VCIM) on the keypad signal circuit. Depending upon the voltage range returned, the VCIM is able to identify which button has been pressed.

This diagnostic procedure supports the following DTC

DTC B2476 Cellular Phone Select Service Switch Malfunction (3 button assembly)

1. The ignition must be in the RUN or ACC position.
2. The system voltage is at least 9.5 volts and no more than 15.5 volts.
3. All the above conditions are present for greater than 300 milliseconds.

1. The VCIM powers the button assembly through the keypad supply voltage circuit for 11.5 milliseconds, turns the power off, then waits for 50 milliseconds and sees a voltage value greater than 1.8 volts on this circuit.
2. The above conditions are present for greater than 300 milliseconds.

1. The VCIM will ignore all inputs from the OnStar® button assembly.
2. No calls can be placed.
3. The OnStar® status LED turns RED.

1. The VCIM powers the button assembly through the keypad supply voltage circuit for 11.5 milliseconds, turns the power off, then waits for 50 milliseconds and sees a voltage value less than 1.8 volts on this circuit.
2. A history DTC clears after 50 malfunction-free ignition cycles.
3. The VCIM receives the clear DTC command from the scan tool.

The OnStar® button assembly consists of 3 buttons, Call/Answer, OnStar® Call Center, and OnStar® Emergency. Ten volts are supplied to the button assembly on the keypad supply voltage circuit. Each of the buttons, when pressed, complete the circuit across a resister allowing a specific voltage to be returned to the vehicle communication interface module (VCIM) on the keypad signal circuit. Depending upon the voltage range returned, the VCIM is able to identify which button has been pressed.

This diagnostic procedure supports the following DTC

DTC B2482 Cellular Phone Select Switch Range/Performance

1. The ignition must be in the RUN or ACC position.
2. The system voltage is at least 9.5 volts and no more than 15.5 volts.
3. All the above conditions are present for greater than 15 seconds.

1. A button is pressed or stuck for more than 15 seconds.
2. The above conditions are present for greater than 15 seconds.

1. The VCIM will ignore all inputs from the OnStar® button assembly.
2. No calls can be placed.
3. The OnStar® status LED turns RED.

1. The button will be declared unstuck after a 50 milliseconds normal cycle.
2. A history DTC clears after 50 malfunction-free ignition cycles.
3. The VCIM receives the clear DTC command from the scan tool.

The navigation antenna is connected to the vehicle communication interface module (VCIM) with a RG-174 coax cable. The VCIM polls the data from the navigation antenna once every second.

This diagnostic procedure supports the following DTCs

1. DTC B2483 GPS Sensor Circuit Low
2. DTC B2484 GPS Sensor Circuit Open

1. The ignition must be in the RUN or ACC position.
2. The system voltage is at least 9.5 volts and no more than 15.5 volts.
3. All the above conditions are present for greater than 1 second.

1. The VCIM does not detect a navigation signal.
2. All the above conditions are present for greater than 1 second.

1. The OnStar® status LED turns red.
2. The OnStar® Call Center cannot locate the vehicle.

1. The VCIM detects the presence of a navigation antenna.
2. A history DTC clears after 50 malfunction-free ignition cycles.
3. The VCIM receives the clear DTC command from the scan tool.

DTC B2483 or B2484

The steering wheel controls are momentary contact switches that connect a series of resistors so that each switch selection corresponds to a fixed resistance value. The body control module (BCM) determines which switch has been pressed by the voltage drop across the corresponding resistance value. The BCM supplies voltage to the steering wheel controls through the rear wiper/washer switch supply voltage circuit. The BCM monitors the switch voltage on the remote radio control signal circuit.

This diagnostic procedure supports the following DTC

DTC B2815 Steering Wheel Controls Illegal Resistance Value

This test is run every 125 milliseconds.

The BCM detects a switch voltage that is higher than normal.

The BCM will ignore the switch command.

Conditions for Clearing the MIL/DTC

1. The DTC will become history if the BCM no longer detects a circuit malfunction.
2. The history DTC will clear after 100 fault free ignition cycles.
3. The DTC can be cleared with a scan tool.

This DTC indicates an internal fault and is set within the vehicle communication interface module (VCIM). No external circuits are involved.

This diagnostic procedure supports the following DTC

DTC U1500 Inter-Device Dedicated Bus Malfunction

The microprocessor runs the program to detect an internal fault during module power up and every 10 seconds thereafter until the module re-enters the sleep mode.

The VCIM detects an internal communication malfunction.

Action Taken When DTC Sets

1. The OnStar® status LED turns RED.
2. The vehicle is unable to connect to the OnStar® Call Center.

1. A current DTC clears when the malfunction is no longer present.
2. A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

1. The diagnostic procedure used for DTC U1500 in OnStar® systems with single module generations of OnStar® differ greatly from previous generations with 2 modules. While these older generations denoted a failure of the 3-wire bus between the modules by setting a U1500, single module OnStar® systems use this DTC to denote an internal module failure. The determination of whether a one or 2-module generation of OnStar® is used should be confirmed. Refer to «OnStar Description and Operation»(ref-277845-S30034518272008012100000) .
2. This DTC may be stored as a history DTC without affecting the operation of the module. If stored only as a history DTC and not retrieved as a current DTC, do not replace the VCIM.
3. If this DTC is retrieved as both a current and history DTC, replace the VCIM.

DTC U1500

Audio System Troubleshooting Hints

Many conditions that affect radio operation may be corrected without removing the radio from the car. Verify the condition, and follow the diagnostic procedures in order to isolate and correct the condition. In order to properly diagnose any audio system problems, ensure that you have a fully charged battery.

Preliminary Inspections

1. Check for any aftermarket equipment that may have been installed on the vehicle. If aftermarket equipment is found disconnect it and check if the audio noise is still present. Inspect that the antenna connector and the antenna coaxial cable are clean and tight.
2. For reception concerns, first determine if the customer is within the listening area of the stations they are attempting to receive.
3. Stations at the lower end of the FM band are more susceptible to audio noises than stations at the higher end.
4. If the noise is only from one speaker check for the following before speaker replacement: Isolate the noise using the J 39916-A CD and Cassette Diagnostic Audio Kit. Inspect the speaker connections to ensure they are clean and tight. Refer to «Testing for Intermittent Conditions and Poor Connections»(ref-277884-S20700666652008012100000) . Inspect for a loose or incorrectly installed speaker or surrounding trim. Loose trim can cause a buzz or flutter which sounds like a malfunctioning speaker.
5. Ignition noise on the FM band may be an indication of an ignition system problem.
6. Inspect that all vehicle grounds are clean, tight and free of corrosion.
7. Inspect the rear defogger grid lines for large breaks or dark spots.
8. Inspect the connections at the radio antenna module if equipped, to ensure that they are clean and tight.
9. Compare the customers vehicle to another of similar model and audio system to determine if the condition is abnormal.

Video Entertainment System Troubleshooting Hints

Schematic Reference: Video System Schematics

1. Many conditions that affect video system operation may be corrected without removing the radio, the digital video disc (DVD) player or the video entertainment overhead console from the vehicle. Make sure to understand all features of system operation before beginning the diagnosis of the system. Verify the condition and follow the diagnostic procedures in order to isolate and correct the condition.
2. Be sure the vehicle battery is fully charged before beginning video entertainment system diagnosis.

1. Perform the «Diagnostic System Check - Vehicle»(ref-277883-S07139257572008012100000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-277883-S33769936482008012100000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-277883-S17347055992008012100000) provide an overview of each diagnostic category.

1. Ignition OFF, disconnect the antenna coax from the digital radio receiver (DRR). Connect the test antenna to the DRR.
2. Turn the ignition ON, radio ON tuned to XM. Is the reception improved? If the reception is not improved, replace the DRR.
3. Ignition OFF. Disconnect the DRR antenna from the coaxial cable. Test the resistance of the antenna coaxial cable center conductor from end to end. Verify the resistance is less than 5 ohms. If the resistance is greater than 5 ohms, replace the antenna coaxial cable.
4. Test the resistance of the antenna coaxial cable outer shield from end to end. Verify the resistance is less than 5 ohms. If the resistance is greater than 5 ohms, replace the antenna coaxial cable.
5. Test the resistance of the antenna coaxial cable between the center conductor and the outer conductor. Verify there is infinite resistance between both conductors. If there is less than infinite resistance between the inner conductor and the outer conductor of the coaxial cable, replace the antenna coaxial cable. If the coaxial cable tests normal, replace the digital radio antenna.

1. The Global Positioning System (GPS) Signal title on the scan tool will display a Yes or No dependant upon whether or not the module sees an increment of the seconds transmitted by GPS signals to the vehicle communication interface module. Upon entering this screen, the GPS Signal title will automatically display Yes, regardless of the presence of time increment, for at least 2 seconds, while the algorithm in the scan tool determines the status of the clock. If increment is found, Yes is continually displayed. If the clock remains static, No is displayed. The scan tool looks for increment every second, regardless of current display.
2. Inaccurate or aged GPS position concerns which are no longer present may have been due to the temporary loss of GPS signal reception by the vehicle. Conditions such as driving through tunnels or parking structures while making an OnStar® keypress will restrict the navigation antenna from a clear view of the satellites in the sky and may have caused this temporary data loss.

Global Positioning System (GPS) Data Not Current or Inaccurate

The customer concern may have been due to a lack of cellular service in a given area or a failure in the National Cellular Network infrastructure that has since been corrected.

OnStar Call Center Remote Function Requests Inoperative

1. The customer concern may have been due to a lack of cellular service in a given area or a failure in the National Cellular Network infrastructure that has since been corrected.
2. If the prompt OnStar Request Ended is heard without pressing the white dot button at the end of an OnStar® keypress, the OnStar® system at one time made a successful cellular connection, but was unable to complete the call. If repeated calls are placed with this result, contact the General Motors Technical Assistance Center.
3. An inaccurate or aged global positioning system (GPS) position may have been due to the temporary loss of GPS signal reception by the vehicle in instances, such as driving through tunnels or parking structures which restrict the navigation antenna from a clear view of the satellites in the sky.

OnStar Symptom Diagnosis

Diagnostic System Check - Entertainment System

Always perform the Diagnostic System Check before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Vehicle .

Antenna System Test

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection (Auxiliary Battery)»(ref-277854-S37314824542008012100000) or «Battery Negative Cable Disconnection and Connection (Single Battery)»(ref-277854-S29426527292008012100000) .
2. Disconnect the antenna lead-in connector from the radio receiver.
3. Measure the resistance from the negative battery cable to the coax outer conductor connector.
4. The resistance measured should be 0.2 ohm or less.
5. Test the following when the resistance is greater than 0.2 ohm: Base of the antenna for a poor connection to body ground The coaxial cable interconnects for a poor connection or corrosion. Test for an open or high resistance from the battery negative cable to the body. Refer to «Circuit Testing»(ref-277884-S17422072462008012100000) and «Wiring Repairs»(ref-277884-S08861102212008012100000) .
6. After finding and correcting the condition, operate the system in order to verify the repair.

Perform the Antenna Checking Procedures after confirming the integrity of the antenna ground.

1. The customer concern may have been due to a lack of cellular service in a given area. A failure in the National Cellular Network infrastructure at the time of the customer's failed connection that has since been repaired may also have been the cause.
2. If an OnStar® emergency call is able to successfully connect the vehicle to the OnStar® Call Center when an OnStar® Call Center button press is not, there may be a failure in the ability of the OnStar® system in the vehicle to be recognized by the local cellular carrier.
3. If the prompt "OnStar® request ended" is heard, without pressing the white dot button at the end of the OnStar® keypress, the OnStar® system at one time has made a successful cellular connection, but was unable to complete the call. If repeated calls are placed with this result, contact General Motors Technical Assistance Center.

Unable to Contact OnStar Call Center

OnStar® Cellular, GPS, and Diagnostic Limitations

The proper operation of the OnStar® System is dependent on several elements outside the components integrated into the vehicle. These include the National Cellular Network Infrastructure, the cellular telephone carriers within the network, and the global positioning system (GPS).

The cellular operation of the OnStar® system may be inhibited by factors such as the user's range from an analog or digital cellular tower, the state of the cellular carriers' equipment, and the location where the call is placed. Making an OnStar® keypress in areas that lack sufficient cellular coverage or have a temporary equipment failure will result in either the inability of a call to complete with a data transfer or the complete inability to connect to the OnStar® Call Center. The OnStar® system may also experience connection issues if the identification numbers for the module, station identification number (STID) and electronic serial number (ESN), are not recognized by the cellular carriers local signal receiving towers. OnStar® cellular connection issues such as these require the assistance of the General Motors Technical Assistance Center OnStar® Group, which coordinates with cellular carriers to resolve connection issues.

The satellites that orbit earth providing the OnStar system with GPS data have almost no failures associated with them. In the event of a no GPS concern, the failure will likely lie with the inability of the system to gain GPS signals because of its location, i.e. in a parking structure, hardware failure, or being mistaken with an OnStar® call which has reached the Call Center without vehicle data.

During diagnostic testing of the OnStar® system, the technician should ensure the vehicle is located in an area that has a clear unobstructed view of the open sky, and preferably, an area where analog or digital cellular calls have been successfully placed. These areas can be found by successfully making an OnStar® keypress in a known good OnStar® equipped vehicle and confirming success with the OnStar® Call Center advisor. Such places can be used as a permanent reference for future OnStar® testing.