Cellular Systems, Entertainment Systems & Navigation Systems: Diagnosis Chevrolet Tahoe III

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

Diagnostic Fault Information

Conditions for Running the DTC

1. Radio ON.
2. Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

1. Vehicle speed from serial data is more than 5 km/h (3 mph) and vehicle speed pulse from the EBCM is 0 km/h (0 mph).
2. Vehicle speed calculated from the navigation processing software is more than 36 km/h (22 mph) and vehicle speed pulse from the EBCM is 0 km/h (0 mph) for 10 seconds continuously.

Action Taken When the DTC Sets

1. Turn by turn route navigation may be inoperative.
2. Vehicle indicated location may be inaccurate.

Conditions for Clearing the DTC

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC clears after 100 malfunction-free ignition cycles.

Circuit/System Testing

1. Ignition OFF, disconnect the X4 harness connector at the radio.
2. Ignition ON, operate the vehicle drive wheels at 5 mph. Test for 3-7 Hertz between the VSS circuit terminal 5 and ground. If not within the specified range, test the VSS circuit for an open, high resistance, short to ground or short to voltage. If the circuit tests normal replace the EBCM.
3. If the circuit tests normal, replace the radio.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Radio ON.
2. Battery voltage must be between 9-16 volts.

The audio amplifier detects an over-heat condition greater than 95°C (203°F) of the internal amplifier circuitry.

The audio amplifier will shut down and all speakers will be inoperative.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Diagnostic Aids

Extended use or extremely high volume especially in warm weather conditions may cause this DTC to set. Under these conditions it may be normal for this DTC to set to prevent permanent damage to the audio amplifier circuitry.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provide an overview of each diagnostic category.

The radio is ON.

Speakers located in the front A-pillar are connected to the same channel as the speaker in the door. A DTC will only set after the amplifier only on up-level radios.

Without Amplifier

1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
4. If all circuits test normal, replace the speaker.

DTC Set By The Radio UQA

1. Ignition OFF, disconnect the X3 harness connector at the amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 15 Left front low level audio signal (-) - terminal 7 Right front low level audio signal (+) - terminal 14 Right front low level audio signal (-) - terminal 6 Left rear low level audio signal (+) - terminal 13 Left rear low level audio signal (-) - terminal 5 Right rear low level audio signal (+) - terminal 12 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the amplifier.

DTC Set By Radio UQA with U42

1. Ignition OFF, disconnect the X3 harness connector at the amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 15 Left front low level audio signal (-) - terminal 7 Right front low level audio signal (+) - terminal 14 Right front low level audio signal (-) - terminal 6 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. Ignition OFF, reconnect the X3 harness connector at the amplifier.
4. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 1 Left rear low level audio signal (-) - terminal 2 Right rear low level audio signal (+) - terminal 3 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
6. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
7. Disconnect the X3 harness connector at the amplifier.
8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 13 Left rear low level audio signal (-) - terminal 5 Right rear low level audio signal (+) - terminal 12 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
9. If all circuits test normal, replace the amplifier.

DTC Set By Radio UQA with Y91 and U42 or UQS and U42

1. Ignition OFF, disconnect the X3 and X4 harness connectors at the amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 11 X3 Left front low level audio signal (-) - terminal 12 X3 Right front low level audio signal (+) - terminal 3 X3 Right front low level audio signal (-) - terminal 4 X3 Left rear low level audio signal (+) - terminal 11 X4 Left rear low level audio signal (-) - terminal 12 X4 Right rear low level audio signal (+) - terminal 3 X4 Right rear low level audio signal (-) - terminal 4 X4 Subwoofer low level audio signal (+) - terminal 5 X4 Subwoofer low level audio signal (-) - terminal 6 X4 Center Channel low level audio signal (+) - terminal 13 X4 Center Channel low level audio signal (-) - terminal 14 X4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the amplifier.

DTC Set By Radio UQA with Y91 and U42 or UQS and U42

1. Ignition OFF, disconnect the X3 and X4 harness connector at the amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 11 X3 Left front low level audio signal (-) - terminal 12 X3 Right front low level audio signal (+) - terminal 3 X3 Right front low level audio signal (-) - terminal 4 X3 Subwoofer low level audio signal (+) - terminal 5 X4 Subwoofer low level audio signal (-) - terminal 6 X4 Center Channel low level audio signal (+) - terminal 13 X4 Center Channel low level audio signal (-) - terminal 14 X4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. Ignition OFF, reconnect the X3 harness connector at the amplifier.
4. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 1 Left rear low level audio signal (-) - terminal 2 Right rear low level audio signal (+) - terminal 3 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
6. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
7. Disconnect the X2 harness connector at the amplifier.
8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 15 Left rear low level audio signal (-) - terminal 14 Right rear low level audio signal (+) - terminal 16 Right rear low level audio signal (-) - terminal 8 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
9. If all circuits test normal, replace the amplifier.

DTC Set by Audio Amplifier UQA

1. Ignition OFF, disconnect the X1 and X2 connectors at the amplifier.
2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 3 X2 Right front speaker output (+) - terminal 2 X2 Right front low speaker output (-) - terminal 1 X2 Left rear speaker output (+) - terminal 8 X2 Left rear speaker output (-) - terminal 7 X2 Right rear speaker output (+) - terminal 6 X2 Right rear speaker output (-) - terminal 5 X2 Left or rear subwoofer speaker output (+) - terminal 7 X1 Left or rear subwoofer speaker output (-) - terminal 3 X1 Right subwoofer speaker output (+) - terminal 6 X1 Right subwoofer speaker output (-) - terminal 2 X1 If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 3 X2 Right front speaker output (+) - terminal 2 X2 Right front low speaker output (-) - terminal 1 X2 Left rear speaker output (+) - terminal 8 X2 Left rear speaker output (-) - terminal 7 X2 Right rear speaker output (+) - terminal 6 X2 Right rear speaker output (-) - terminal 5 X2 Left or rear subwoofer speaker output (+) - terminal 7 X1 Left or rear subwoofer speaker output (-) - terminal 3 X1 Right subwoofer speaker output (+) - terminal 6 X1 Right subwoofer speaker output (-) - terminal 2 X1 If less than the specified value, test both circuits of the affected speaker for a short to ground.
4. If all circuits test normal, reconnect all harness connectors at the amplifier.
5. Ignition ON, radio ON, disconnect the appropriate speaker.
6. Test for 5.0-7.5 volts between the signal circuit terminals and ground. If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the amplifier. If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
7. If the circuit tests normal, replace the appropriate speaker.

DTC Set by Audio Amplifier UQA with Y91 or UQS

1. Ignition OFF, disconnect the X1 and X2 connectors at the amplifier.
2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 5 X2 Right front speaker output (+) - terminal 7 X2 Right front speaker output (-) - terminal 6 X2 Left rear speaker output (+) - terminal 15 X2 Left rear speaker output (-) - terminal 14 X2 Right rear speaker output (+) - terminal 16 X2 Right rear speaker output (-) - terminal 8 X2 Front center speaker output (+) - terminal 13 X2 Front center speaker output (-) - terminal 12 X2 Right rear midrange speaker output (+) - terminal 3 X2 Right rear midrange speaker output (-) - terminal 2 X2 Left rear midrange speaker output (+) - terminal 11 X2 Left rear midrange speaker output (-) - terminal 10 X2 Left or rear subwoofer speaker output (+) - terminal 1 X1 Left or rear subwoofer speaker output (-) - terminal 2 X1 Right subwoofer speaker output (+) - terminal 7 X1 Right subwoofer speaker output (-) - terminal 3 X1 If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 5 X2 Right front speaker output (+) - terminal 7 X2 Right front speaker output (-) - terminal 6 X2 Left rear speaker output (+) - terminal 15 X2 Left rear speaker output (-) - terminal 14 X2 Right rear speaker output (+) - terminal 16 X2 Right rear speaker output (-) - terminal 8 X2 Front center speaker output (+) - terminal 13 X2 Front center speaker output (-) - terminal 12 X2 Right rear midrange speaker output (+) - terminal 3 X2 Right rear midrange speaker output (-) - terminal 2 X2 Left rear midrange speaker output (+) - terminal 11 X2 Left rear midrange speaker output (-) - terminal 10 X2 Left or rear subwoofer speaker output (+) - terminal 1 X1 Left or rear subwoofer speaker output (-) - terminal 2 X1 Right subwoofer speaker output (+) - terminal 7 X1 Right subwoofer speaker output (-) - terminal 3 X1 If less than the specified value, test both circuits of the affected speaker for a short to ground.
4. If all circuits test normal, reconnect all harness connectors at the amplifier.
5. Radio ON, disconnect the appropriate speaker.
6. Test for 5.0-7.5 volts between the signal circuit terminals and ground. If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the amplifier. If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
7. If the circuit tests normal, replace the appropriate speaker.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The ignition is ON.

1. Ignition OFF, disconnect the antenna coax from the DRR. Connect the EL-48028 to the DRR. See «Special Tools»(ref-364479-S40951042282010063000000) .
2. Radio ON, tuned to XM, verify DTC B1259 is not set as current. If the DTC is current, replace the DRR.
3. Ignition OFF, reconnect the antenna coax to the DRR, disconnect the digital radio antenna coax from the digital radio antenna.
4. Ignition ON, test for 4.5-5.5 volts between the antenna coax center terminal and the coax outer shield. If not within the specified range, replace the antenna coax.
5. If all circuits test normal, replace the digital radio antenna.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Radio is ON
2. The system voltage is at between 9 volts and 16 volts

A short to voltage, short to ground, or an open is seen on the remote enable circuit

Amplifier functions are disabled

1. A current DTC clears when the condition for setting the DTC is no longer present
2. A history DTC clears after 100 malfunction-free ignition cycles

1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
2. Ignition ON, radio ON and un-muted, test for 0.5-1.0 volts between the amplifier control circuit terminal 11 and ground. If greater than the specified value, test the amplifier control circuit for a short to voltage. If the circuit tests normal, replace the radio. If less than the specified value, test the amplifier control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the amplifier.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition ON.
2. Battery voltage must be between 9-16 volts.

The DTC will set when the radio detects a short to voltage, short to ground, or an open/high resistance in the video display mode control circuit 400 ms after the radio activates the remote enable circuit.

The radio sets the DTC and defaults the video display to normal mode.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

1. Ignition OFF, disconnect the harness connector at the rear video display.
2. Ignition ON, test for 100-300 Hz at the control circuit terminal 10. If not within the specified range, test the control circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the rear video display.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition ON.
2. Battery voltage must be between 9-16 volts.

The DTC will set when the radio detects a short to voltage, short to ground, or an open/high resistance in the video display brightness control circuit 400 ms after the radio activates the remote enable circuit.

The radio sets the DTC and defaults the video display to full brightness.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

1. Ignition OFF, disconnect the harness connector at the rear video display.
2. Ignition ON, test for 100-300 Hz at the control circuit terminal 9. If not within the specified range, test the control circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the rear video display.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition ON.
2. Battery voltage must be between 9-16 volts.

The DTC will set when the rear audio/HVAC module detects a short to voltage, short to ground, or an open/high resistance in the infrared module voltage signal circuit.

The rear audio/HVAC module sets the DTC and the infrared module will be disabled.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

1. Ignition OFF, disconnect the harness connector at the infrared module.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal 12 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, rear audio ON, test for 10.0-11.0 volts between the supply voltage circuit terminal 4 and ground. If less than the specified range, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear audio/HVAC module. If greater than the specified range, test the voltage supply circuit for a short to voltage. If the circuit tests normal, replace the rear audio/HVAC module.
4. If all circuits test normal, replace the infrared module.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provide an overview of each diagnostic category.

1. The ignition must be in the RUN or ACC position.
2. The system voltage is at least 9.5 V and no more than 15.5 V.

1. The CIM detects an open, short to ground or short to voltage in the cellular phone microphone signal circuit for 10 seconds or greater.
2. The CIM detects an open/high resistance in the drain wire circuit for 10 seconds or greater.

Actions Taken When the DTC Sets

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

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

Schematic Reference

OnStar Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

OnStar Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-364488-S04114729552010063000000)
2. «Connector Repairs»(ref-364488-S23771656832010063000000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the B24 cellular phone microphone.
2. Test for less than 10 ohms between the low reference circuit terminal A and ground. If greater than the specified range, test the circuit for an open/high resistance.
3. Ignition ON, test for 9.5-10.5 V between the signal circuit terminal B and ground. If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CIM. If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the CIM.
4. If all circuits test normal, replace the B24 cellular phone microphone.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

Circuit Description

The global positioning system (GPS) antenna is connected to the navigation radio by a coaxial cable. The antenna cable also provides a path for DC current for powering the antenna.

1. Radio ON
2. Battery voltage between 9-16 volts
3. The navigation radio tests the GPS antenna every 10 seconds

1. The radio uses the last reported position and the vehicle speed signal to calculate the vehicle position.
2. Route guidance may be inaccurate.
3. Turn by turn navigation may be inaccurate or inoperative.

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

1. Ignition OFF, disconnect the GPS antenna coax cable from the navigation radio.
2. Ignition ON, test for 4.5-5.5 volts between the coax cable connection center conductor at the radio and ground. If not within the specified range, replace the radio.
3. If all circuits test normal, replace the GPS antenna.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition is in the RUN or ACC position.
2. System voltage is between 9.5 V and 15.5 V.
3. The above conditions are present for greater than 1 second.

1. Ignition OFF, disconnect both the GPS and cell coax cable connectors at the K73 telematics communication interface control module.
2. Connect the EL-49903 to the K73 telematics communication interface control module, place the test antenna on the roof of the vehicle. See «Special Tools»(ref-364479-S40951042282010063000000) .
3. Ignition ON, wait 5 minutes, then contact the OnStar call center consultant by pressing the blue OnStar button. A call center consultant should answer the call, ask the consultant to verify the vehicle location to confirm the GPS system is functioning. If the OnStar GPS does not function, replace the K73 telematics communication interface module.
4. Ignition OFF, perform the coax cable test on the coax cable, refer to Component Testing. The coax cable should pass the test. If the coax cable does not pass the test, replace the coax cable.
5. If all circuits test normal, replace the T4 cellular phone and navigation antenna.

Component Testing

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 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 GPS and cellular phone coax cable at both components.
2. Test both for less than 5 ohms between both ends of the coax cables center terminals. If greater than the specified range, replace the failed coax cable.
3. Test for greater than 10k ohms between the coax cable center wire and the outer coax shield. If less than the specified range, replace the coax cable.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition in the RUN or ACC position.
2. System voltage is between 9.5 volts and 15.5 volts.
3. The above conditions are present for greater than 1 second.

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

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

1. The CIM detects the presence of a cellular antenna.
2. A history DTC clears after 50 malfunction-free ignition cycles.

1. Ignition OFF, disconnect the cellular antenna coax from the CIM module and the cellular antenna.
2. Ignition ON, test for less than 1 volt between the antenna coax center terminal and ground. If greater than the specified range, replace the antenna coax.
3. Ignition ON, test for less than 1 volt between the antenna coax outer shield and ground. If greater than the specified range, replace the antenna coax.
4. Test for infinite resistance between the antenna coax center terminal and ground. If less than the specified value, replace the antenna coax
5. Test for infinite resistance between the antenna coax outer shield and ground. If less than the specified value, replace the antenna coax
6. Test for less than 5 ohms at the cellular antenna coax center terminal from end to end. If greater than specified value, replace the cellular antenna coax cable.
7. Test for less than 5 ohms at the cellular antenna coax outer shield from end to end. If greater than specified value, replace the cellular antenna coax cable.
8. Test for infinite resistance between the antenna coax center terminal and the outer shield. If less than specified value, replace the cellular antenna coax cable.
9. If coax cable tests normal, replace the cellular antenna.
10. Clear the DTCs and operate the vehicle within the conditions for running the DTC. Verify DTC B2470 does not set. If the DTC sets, replace the CIM.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The internal backlighting of the navigation display screen located in the navigation radio.

1. Radio ON.
2. Battery voltage must be between 9-16 volts.

1. The navigation radio tests the navigation display backlighting every 1 second.
2. The radio determines there is a malfunction or overheat condition in the navigation display backlighting.

Navigation backlighting may be too bright, dim or blank.

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

Occasionally it is possible to overheat the navigation display backlighting due to excessive ambient heat inside the vehicle. In this instance it may be necessary to allow time for the display to cool.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition ON.
2. Battery voltage must be between 9-16 V.

1. Ignition OFF, disconnect the harness connector at the A10 inside rearview mirror.
2. Test for less than 10 ohms between the mirror ground circuit terminal 8 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for less than 1 V between the keypad signal circuit terminal 11 and ground. If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the CIM.
4. Ignition OFF, test for 600k-800k ohms between the keypad signal circuit terminal 11 and ground. If less than the specified range, test the keypad signal circuit for a short to ground. If the circuit tests normal, replace the CIM. If greater than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the CIM.
5. Ignition ON, test for 9.5-10.5 V between the keypad supply voltage circuit terminal 12 and ground. If less than the specified range, test the supply voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the CIM. If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the CIM.
6. If all circuits test normal, test or replace the button assembly.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provide an overview of each diagnostic category.

1. Ignition ON.
2. Battery voltage must be between 9-16 V.
3. The CIM tests the antenna once every second.

1. The OnStar ® status LED turns red.
2. Bluetooth ® functionality is disabled.

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

Schematic Reference

OnStar Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

OnStar Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-364488-S04114729552010063000000)
2. «Connector Repairs»(ref-364488-S23771656832010063000000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

Scan Tool Reference

Control Module References for scan tool information

1. Verify the Bluetooth ® antenna is properly connected to the CIM and is not damaged. If the antenna is disconnected or damaged, repair or replace as necessary.
2. Ignition ON, verify the DTC B2485 is not set. If the DTC is set, replace the Bluetooth ® antenna. Clear the DTC and cycle the ignition OFF then back ON. If the DTC resets as current, replace the CIM.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Radio/Audio System. Refer to «Checking Aftermarket Accessories»(ref-364488-S07680217832010063000000) .
2. Inspect for easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Bluetooth Malfunction»(ref-364479-S10174915012010063000000)
2. «OnStar Global Positioning System (GPS) Data Not Current or Inaccurate»(ref-364479-S00994735982010063000000)
3. «OnStar Microphone Malfunction»(ref-364479-S26242926972010063000000)
4. «OnStar Audio Malfunction»(ref-364479-S11187413952010063000000)
5. «OnStar Button LED Malfunction»(ref-364479-S20366814602010063000000)
6. «OnStar Call Center Remote Function Requests Malfunction»(ref-364479-S23901639822010063000000)
7. «OnStar Button Malfunction»(ref-364479-S16163879692010063000000)
8. «Unable to Contact OnStar Call Center»(ref-364479-S19832442832010063000000)
9. «OnStar Voice Recognition Malfunction»(ref-364479-S36848848712010063000000)
10. «OnStar Steering Wheel Control Functions Malfunction»(ref-364479-S33902054092010063000000)

Symptoms - Entertainment

1. Inspect for aftermarket devices which could affect the operation of the Radio/Audio system. Refer to «Checking Aftermarket Accessories»(ref-364488-S07680217832010063000000) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Speaker Malfunction»(ref-364479-S30109252362010063000000)
2. «Audio/Video Player Adapter - Audio or Video Malfunction»(ref-364479-S28520544372010063000000)
3. «Dual DVD Rear Seat Entertainment Headrest Display Malfunction»(ref-364479-S21725928052010063000000)
4. «Dual DVD Rear Seat Entertainment Headrest Audio Malfunction»(ref-364479-S18940785312010063000000)
5. «Dual DVD Rear Seat Entertainment Headrest Wireless Headphones Malfunction»(ref-364479-S26078322782010063000000)
6. «Dual DVD Rear Seat Entertainment Headrest Remote Malfunction»(ref-364479-S05749662582010063000000)
7. «Noise Compensated Volume Malfunction»(ref-364479-S42048575312010063000000)
8. «Radio Audio Malfunction at Rear Seat Audio (RSA) Control»(ref-364479-S18888970392010063000000)
9. «Radio Displays LOC, LOCKED, or CODE»(ref-364479-S28381269812010063000000)
10. «Radio Displays CAL or CAL ERR»(ref-364479-S26928918142010063000000)
11. «Radio Poor Reception»(ref-364479-S16235090002010063000000)
12. «Rear Seat Radio Controls Inoperative»(ref-364479-S10988560332010063000000)
13. «Video Display Malfunction»(ref-364479-S01234309252010063000000)
14. «Video Entertainment System Malfunction»(ref-364479-S34961544792010063000000)
15. «Video Entertainment System Remote Control Malfunction»(ref-364479-S37781468752010063000000)
16. «Video Entertainment System Wireless Headphone Malfunction»(ref-364479-S40084381832010063000000)

Symptoms - Navigation Systems

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
2. Review «Navigation System Description and Operation»(ref-364479-S19038558002010063000000) in order to familiarize yourself with the system functions.

1. Inspect for aftermarket devices which could affect the operation of the navigation system components. Refer to «Checking Aftermarket Accessories»(ref-364488-S07680217832010063000000) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «No Global Positioning System (GPS) Reception»(ref-364479-S11892338262010063000000)
2. «Navigation System - Voice Recognition Malfunction»(ref-364479-S03198429012010063000000)
3. For radio/audio related symptoms, refer to «Symptoms - Entertainment»(ref-364479-S31150355622010063000000) .

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

Verify the external audio or video device is operating normally before performing this diagnostic procedure.

1. Ignition OFF, disconnect the X3 harness connector at the radio.
2. Ignition ON, test for less then 1 volt between the appropriate signal circuit terminals listed below and ground. Auxiliary audio left signal (+) - terminal 1 Auxiliary audio right signal (+) - terminal 2 Auxiliary audio drain wire (-) - terminal 9 Auxiliary video signal (+) - terminal 8 Auxiliary video drain wire (+) - terminal 16 If greater then specified range, test the circuit for a short to voltage.
3. Test for infinite resistance between the terminals listed below and ground. Auxiliary audio left signal (+) - terminal 1 Auxiliary audio right signal (+) - terminal 2 Auxiliary audio drain wire (-) - terminal 9 Auxiliary video signal (+) - terminal 8 Auxiliary video drain wire (+) - terminal 16 If less then the specified value, test the circuit for a short to ground.
4. Test for less then 5 ohm between the terminals on the radio X3 harness connector and the external terminals on the audio/video adaptor listed below: Auxiliary audio left signal (+) - terminal 1 and the inside of the center (white) jack Auxiliary audio right signal (+) - terminal 2 and the inside of the right (red) jack Auxiliary audio drain wire (-) - terminal 9 and the outside of both the center (white), and the right (red) jacks Auxiliary video signal (+) - terminal 8 and the inside of the left (yellow) jack Auxiliary video drain wire (+) - terminal 16 and the outside of the left (yellow) jack If greater then the specified value, test the circuit for an open/high resistance. If the circuit tests normal, replace the adaptor.
5. If all circuits test normal, replace the radio.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provide an overview of each diagnostic category.

1. The purpose of this diagnostic is to verify the ability of the CIM to pair to a Bluetooth ® device.
2. Before performing this test, verify compatibility of the cellular phone(s) the customer is attempting to use with the vehicle. Based on the cellular phone's service provider and the manufacturer's implementation of Bluetooth ®, not all phones support all available Bluetooth ® functionality. A vehicle and feature compatibility list will be provided via the GM Bluetooth ® website: http://www.gm.com/vc/bluetooth/
3. If the vehicle passes the following tests and a compatible device is being used, the concern may be due to a device malfunction or an incomplete/improper pairing attempt.
4. A Bluetooth ® test tool or equivalent can also be used to verify the ability of the customers cellular phone(s) to pair with another device.

Schematic Reference

OnStar Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

OnStar Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-364488-S04114729552010063000000)
2. «Connector Repairs»(ref-364488-S23771656832010063000000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-364488-S16423338542010063000000)
4. «Wiring Repairs»(ref-364488-S17530456672010063000000)

Scan Tool Reference

Control Module References for scan tool information

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

When diagnosing digital radio concerns, the vehicle should be located outside with an unobstructed view of the southern sky to ensure proper reception of the satellite signal. Reception may be limited, intermittent or not possible inside structures or under heavy cover.

Digital Radio Antenna Circuit Malfunction

1. Ignition OFF, disconnect the antenna coax from the DRR. Connect the EL-48028 to the DRR. See «Special Tools»(ref-364479-S40951042282010063000000) .
2. Ignition ON, radio tuned to XM, verify XM reception is clear and uninterrupted. If reception is not clear, replace the DRR.
3. Ignition OFF, reconnect the antenna coax to the DRR, disconnect the digital radio antenna coax from the digital radio antenna.
4. Ignition ON, test for 4.5-5.5 volts between the antenna coax center terminal and the coax outer shield. If not within the specified range, replace the antenna coax.
5. If all circuits test normal, replace the digital radio antenna.

Digital Radio Output Circuit Malfunction

1. Ignition OFF, disconnect the X2 harness connector at the radio.
2. Ignition ON, radio ON and tuned to XM, test for varying mV AC voltage between the following signal circuit terminals listed below and ground: Left audio signal (+) - connector X2, terminal 1 Right audio signal (+) - connector X2, terminal 2 Left audio signal (-) - connector X2, terminal 9 Right audio signal (-) - connector X2, terminal 10 If the varying mV A/C voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the DRR.
3. If all circuits test normal, replace the radio.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The DVD displays are grounded and powered by the DVD control module. When a movie is playing, the video signals are sent from the player, to the DVD control module, and back to the display. This allows the other monitor to source the same video as the player with the disc.

One Display Inoperative

1. Ignition OFF, disconnect the X1 harness connector at the appropriate display.
2. Ignition ON, test for less than 5 ohms between the ground circuit terminal 5 and ground. If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the DVD control module.
3. Ignition ON, test for B+ between the ignition voltage circuit terminal 6 and ground. If less than the specified value, B+ circuit for an open/high resistance. If the circuit tests normal, replace the DVD control module.
4. Ignition OFF, reconnect the X1 harness connector, and disconnect the X2 harness connector at the display.
5. Ignition ON, test for 4.5-5.5 V between the terminals listed below and ground: I2C Clock Signal - terminal 5 I2C Data - terminal 6 If less than specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the DVD control module. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the DVD control module.
6. If all circuits test normal, replace the appropriate display.

Both Displays Inoperative

1. Ignition OFF, disconnect the X1 harness connector at the DVD control module.
2. Test for less 5 ohms between the ground circuit terminal 3 and ground. If the greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for B+ between the accessory voltage circuit terminal and ground. If less than the specified value, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition OFF, Reconnect the X1 harness connector at the DVD control module
5. Disconnect the X1 harness connector at the driver seat headrest.
6. Ignition ON, test for less than 5 ohms between the ground circuit terminal 5 and ground. If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the DVD control module.
7. Ignition ON, test for B+ between the ignition voltage circuit terminal 6 and ground. If less than the specified value, B+ circuit for an open/high resistance. If the circuit tests normal, replace the DVD control module.
8. Ignition OFF, reconnect the X1 harness connector, and disconnect the X2 harness connector at the display.
9. Ignition ON, test for 4.5-5.5 V between the terminals listed below and ground: I2C Clock Signal - terminal 5 I2C Data - terminal 6 If less than specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the DVD control module. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the DVD control module.
10. If all circuits test normal, replace the appropriate display.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

One Display Inoperative (Dual Display)

1. Turn ON the ignition, press the power button on the suspect display. Verify the suspect DVD display does not power up. If the DVD display powers up but the screen is blank and will not play any DVDs, replace the DVD display.
2. At the DVD control module, touch a test lamp at the back of the suspect black or red connector between terminal 6 and ground. Verify that a test lamp illuminates between terminal 6 and ground. If the test lamp does not illuminate, replace the DVD control module.
3. At the DVD control module, touch a test lamp at the back of the suspect black or red connector between terminal 5 and B+. Verify that a test lamp illuminates between terminal 5 and B+. If the test lamp does not illuminate, replace the DVD control module.
4. Disconnect the suspect black or red connector from the suspect DVD display. At the black or red DVD display connector, Test for B+ at terminal 6. If B+ is not present replace the DVD display harness.
5. At the black or red DVD display connector, test for less than 1.0 ohm between the ground circuit terminal 5 and ground. If greater than the specified range, replace the DVD display harness. If all circuits test normal replace the suspect DVD display.

Display Inoperative (Single Display) or Both Displays Inoperative (Dual Display)

1. Turn ON the ignition, press the power button on both suspect displays. Verify the suspect DVD displays do not power up. If the DVD display powers up but the screen is blank and will not play any DVDs, replace the suspect DVD display.
2. Disconnect the 2 wire connector from the DVD control module. At the 2 wire harness connector, test for less than 1.0 ohm between the ground circuit terminal and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. At the DVD control module 2 wire harness connector, verify that a test lamp illuminates between the B+ circuit terminal and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Reconnect the 2 wire harness connector at the DVD control module
5. At the DVD control module, touch a test lamp at the back of the black or red connector between terminal 1 and ground. Verify that a test lamp illuminates between terminal 1 and ground. If the test lamp does not illuminate, replace the DVD control module.
6. At the DVD control module, touch a test lamp at the back of the suspect black or red connector between terminal 2 and B+. Verify that a test lamp illuminates between terminal 2 and B+. If the test lamp does not illuminate, replace the DVD control module.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The infrared transmitter is internal to the DVD display and is grounded and powered by the DVD control module. When listening to the headphones, the infrared transmitter sends an infrared signal to the headphones. There are two channels on the headphones, the first channel is dedicated to the driver side video screen, and the other channel is dedicated to the passenger side. The audio that is sent over the DVD audio signal circuits is a varying AC voltage.

Dual DVD Rear Seat Entertainment Audio Malfunction - With FM Antenna

1. Turn ON the ignition, tune the radio to station 88.3, 88.7, 89.1, 89.5, 89.9, or 90.3MHz. Chose the station that has the least amount of regular audible radio reception.
2. Headrest DVD displays ON, insert a DVD and operate the DVD player in play mode.
3. DVD playing, DVD Surround Sound ON, set the DVD Player to the same station as the radio. Verify audio can be heard through the radio. If the DVD audio can be heard review the system operation with the customer.
4. Verify the DVD player is in play mode.
5. At the DVD control module, test for AC voltage between terminal 6 and terminal 3 or 4 with a DMM at the back of the black or red connector. If AC voltage is present replace the DVD control module.
6. Turn the DVD player off and disconnect both connectors from the DVD display that was playing the DVD.
7. Swap the two connectors on the display and swap the two corresponding connectors at the DVD control module. Verify the DVD audio now operates normally. If the DVD audio now operates normally, replace the DVD display harness. It the DVD audio is still inoperative replace the suspect DVD display.

Dual DVD Rear Seat Entertainment Audio Malfunction - Without FM Antenna

1. Turn ON the ignition, tune the radio to station 88.3, 88.7, 89.1, 89.5, 89.9, or 90.3MHz. Chose the station that has the least amount of regular audible radio reception.
2. Press the power button on the headrest DVD displays. Insert a DVD and operate the DVD player in play mode. Verify the DVD audio is distorted on one of the above stations. If the DVD audio can be heard review the system operation with the customer.
3. Turn the DVD player off and disconnect both connectors from the DVD display that was playing the DVD.
4. Swap the two connectors on the display and swap the two corresponding connectors at the DVD control module. Verify the DVD audio now operates normally. If the DVD audio now operates normally, replace the DVD display harness. If the DVD audio distortion persists, replace the DVD control module.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Turn ON the ignition, press the power button on one of the displays and insert a DVD. Operate the DVD player in play mode.
2. Press the power button on the other display. Press the source button to view the DVD video playing on the adjacent display. Verify that the video displays do not synchronize. Test or repair the suspect video in/out signal circuit for a short to B+, short to ground or open circuit. If all circuits test normal replace the DVD control module.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The infrared transmitter is internal to the DVD display and is grounded and powered by the DVD control module. When listening to the headphones, the infrared transmitter sends an infrared signal to the headphones. There are two channels on the headphones, the first channel is dedicated to the driver side video screen, and the other channel is dedicated to the passenger side. The audio that is sent over the DVD audio signal circuits is a varying AC voltage.

Note. Select both channels by switching the channel selector located on the side of the headphones and verify the volume is turned up. Also verify that the headphones are not in mute mode. Press the Sound Around ON/OFF button on the remote to change audio muting status.

1. Ignition OFF, disconnect the appropriate seat headrest X2 connector at the monitor.
2. Ignition ON, DVD playing, test for 15-40 mV A/C between the terminals on the monitor listed below and ground. Right Audio Signal - terminal 3 Left Audio Signal - terminal 4 If the not within the specified range, replace the appropriate DVD display.
3. Ignition OFF, reconnect the harness connector at the monitor.
4. Disconnect the appropriate seat headrest X2 connector at the DVD control module.
5. Ignition ON, DVD playing, test for 15-40 mV A/C between the terminals on the monitor listed below and ground. Right Audio Signal - terminal 3 Left Audio Signal - terminal 4 If the not within the specified range, replace the wiring harness.
6. If all circuits test normal, replace the DVD control module.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The infrared transmitter is internal to the DVD display and is grounded and powered by the DVD control module. When listening to the remote control, the remote sends an infrared signal to the infrared receiver. No external circuits are involved.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. The 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.

1. Disconnect the navigation antenna coax cable from the CIM.
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 navigation 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 navigation antenna.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The Apple iPod® is connected to the personal audio link (PAL) through a dedicated interface cable. The cable allows the iPod the ability to share serial data communication, audio signals, power and ground with the vehicle. The T-harness used to connect the PAL module shares the same power and grounds as the radio. The audio signal circuits are shared with the Digital Radio Receiver audio circuits. The PAL module receives Data communication by connecting inline with the DRR.

1. After PAL is installed, it is only possible to communicate with the DRR when the radio is ON and XM band selected.
2. If radio is OFF, or tuned to any other band a NO COMM message for DRR is displayed on Tech2 (Vehicle DTC Check).
3. PAL module maintains a persistent B1000 code that cannot be cleared, and does not affect operation.
4. If PAL module loses power or ground, BCM and Radio set DTCs for loss of communication with DRR.
5. The iPod® interface connector is susceptible to vibration and movement damage. It is recommended that excessive movement of the iPod® and cable be avoided while driving.

1. Ignition OFF, disconnect the harness connector at the PAL module.
2. Test for less than 5 ohms between terminal 9 and ground. If greater than specified value, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between terminal 16 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
4. Ignition OFF, reconnect the harness connector at the PAL module.
5. Disconnect the X2 harness connector at the radio.
6. Radio ON, iPod sourced and playing, test for a varying mV AC voltage between the following signal circuit terminals listed below and ground. Left audio signal (+) - terminal 1 Right audio signal (+) - terminal 2 Left audio signal (-) - terminal 9 Right audio signal (-) - terminal 10 If the varying mV A/C voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuits tests normal, replace the PAL module.
7. If all circuits test normal, replace the radio.

PAL LED Indicator Malfunction

1. Ignition OFF, disconnect the PAL harness connector.
2. Ignition ON, verify that a test lamp illuminates between the PAL B+ circuit terminal and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
3. Verify that a test lamp illuminates at both PAL ground circuit terminals and B+. If the test lamp does not illuminate, test the ground circuits for an open/high resistance.
4. If all circuits test normal, replace the PAL.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition OFF, disconnect the harness connector at the cellular microphone.
2. Test for less than 10 ohms between the low reference circuit terminal A and ground. If greater than the specified range, test the circuit for an open/high resistance.
3. Ignition ON, test for 9.5-10.5 V between the signal circuit terminal B and ground. If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CIM. If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the CIM.
4. If all circuits test normal, replace the cellular microphone.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Verify the OnStar® voice recognition is operating normally. If the OnStar® voice recognition is inoperative, refer to «OnStar Microphone Malfunction»(ref-364479-S26242926972010063000000) .
2. Ignition OFF, disconnect the radio harness connector X1 and CIM harness connector X3.
3. Test for less than 1 volt on the voice recognition audio signal circuit radio harness connector terminal 4 and ground. If greater than specified value, test the circuit for a short to voltage.
4. Test for greater than 1 ohm between the voice recognition audio signal circuit radio harness connector terminal 4 and ground. If less than specified value, test the circuit for a short to ground.
5. Test for less than 1 ohm between the voice recognition audio signal circuit radio harness connector terminal 4 and the voice recognition audio signal circuit CIM harness connector terminal 2. If greater than specified value, test the circuit for an open/high resistance.
6. Test for less than 1 volt on the voice recognition audio low reference circuit radio harness connector terminal 5 and ground. If greater than specified value, test the circuit for a short to voltage..
7. Test for greater than 1 ohm between the voice recognition audio low reference circuit radio harness connector terminal 5 and ground. If less than specified value, test the circuit for a short to ground.
8. Test for less than 1 ohm between the voice recognition audio low reference circuit radio harness connector terminal 5 and the voice recognition audio low reference signal circuit CIM harness connector terminal 4. If greater than specified value, test the circuit for an open/high resistance.
9. If all circuits test normal, replace the radio.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition OFF, disconnect the X2 harness connector at the radio.
2. Ignition ON, test for a varying AC voltage between the following signal circuit terminals listed below and ground when the OnStar® Call Center button is pressed. Audio Signal Circuit- terminal 7 Audio Common Circuit- terminal 15 If AC voltage was not present, test the circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the CIM.
3. If all circuits test normal, replace the radio.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The global positioning system (GPS) antenna is connected to the navigation radio by a shielded coaxial cable. The antenna cable also provides a path for DC current for powering the GPS antenna.

Note. The global positioning system (GPS) requires a clear line of sight to the sky to operate properly. In most cases the GPS will not have reception near tall buildings or inside structures.

1. Ignition OFF, disconnect the GPS antenna coax cable from the navigation radio.
2. Ignition ON, test for 4.5-5.5 V between the coax cable center conductor terminal at the radio and ground. If not within the specified range, replace the radio.
3. If all circuits test normal, replace the GPS antenna.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Turn the ignition ON. Disconnect the noise compensation microphone.
2. Measure for 7-9 volts between the noise compensation microphone supply circuit terminal A and the drain circuit terminal B. If the voltage is less than the specified range, test the circuits for a short to ground, or an open/high resistance. If the circuit tests normal, replace the auido amplifier. If the voltage is greater than the specified range, test the circuits for a short to voltage. If the circuit tests normal, replace the audio amplifier.
3. If all circuits test normal, replace the noise compensation microphone.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The OnStar® status LEDs are located with the OnStar buttons. The green LED is illuminated when the system is ON and operating normally. When the green LED is green and flashing, it is an indication that a call is in progress. When the red LED is illuminated, a system malfunction is present. In the event there is a system malfunction and the OnStar® system is still able to make a call, the LED will flash red during the call. The OnStar® LEDs are controlled by the communication interface module (CIM) via the keypad green LED signal circuit and the keypad red LED signal circuit.

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Doors closed, courtesy lamps OFF, test for less than 10 ohms between the ground circuit terminal 8 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, command the green LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal 14 and ground. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the CIM.
4. Command the green LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal 14 and ground. If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CIM.
5. Command the red LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal 15 and ground. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the CIM.
6. Command the red LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal 15 and ground. If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the CIM.
7. If all circuits test normal, replace the inside rearview mirror.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

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 that has since been corrected.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Test for less than 10 ohms between the mirror ground circuit terminal 8 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for less than 1 V between the keypad signal circuit terminal 11 and ground. If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the CIM.
4. Ignition OFF, test for 600k-800k ohms between the keypad signal circuit terminal 11 and ground. If less than the specified range, test the keypad signal circuit for a short to ground. If the circuit tests normal, replace the CIM. If greater than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the CIM.
5. Ignition ON, test for 9.5-10.5 V between the keypad supply voltage circuit terminal 12 and ground. If less than the specified range, test the supply voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the CIM. If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the CIM.
6. If all circuits test normal, test or replace the button assembly.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provide an overview of each diagnostic category.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provide an overview of each diagnostic category.

1. Ignition OFF, disconnect the X1 harness connector at the rear seat audio (RSA) controller.
2. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Radio ON, test for battery voltage between the battery positive voltage circuit terminal 5 and ground. If less than the specified range, test the voltage circuit for a short to ground or an open/high resistance.
4. If all circuits test normal, replace the rear seat audio controller.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

Theft Lock is activated when the VIN as received over the data communication circuit and the VIN as stored in the module memory do not match. This also occurs when no VIN is received over the data communication circuit. The only circuit required is the communication line.

This symptom may be an indication that an incorrect radio is installed in the vehicle, or that the radio was replaced without reprogramming with the new information.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The Apple iPod® is connected to the personal audio link (PAL) through a dedicated interface cable. The cable allows the iPod the ability to share serial data communication, audio signals, power and ground with the vehicle. The T-harness used to connect the PAL module shares the same power and grounds as the radio. The audio signal circuits are shared with the Digital Radio Receiver audio circuits. The PAL module receives Data communication by connecting inline with the DRR.

1. After PAL is installed, it is only possible to communicate with the DRR when the radio is ON and XM band selected.
2. If radio is OFF, or tuned to any other band a NO COMM message for DRR is displayed on Tech2 (Vehicle DTC Check).
3. PAL module maintains a persistent B1000 code that cannot be cleared, and does not affect operation.
4. If PAL module loses power or ground, BCM and Radio set DTCs for loss of communication with DRR.
5. The iPod® interface connector is susceptible to vibration and movement damage. It is recommended that excessive movement of the iPod® and cable be avoided while driving.

1. Ignition OFF, disconnect the harness connector at the PAL module.
2. Test for less than 5 ohms between terminal 9 and ground. If greater than specified value, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between terminal 16 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
4. Ignition OFF, reconnect the harness connector at the PAL module.
5. Ignition ON, set the radio to the iPod® interface menu and attempt to operate audio from the iPod®. If the iPod® fails to communicate with the radio, replace the interface cable.
6. Near the BCM connector, verify the serial data circuit from PAL is properly spliced to the serial data circuit. If the serial data circuit is not connected, reconnect the circuit.
7. Ignition OFF, disconnect the PAL module and the X1 radio harness connector.
8. Test for less than 1 ohms between terminal 9 at the X1 radio harness connector and terminal 5 at the X1 PAL module harness connector. If greater than specified value, replace the T-harness.
9. If all systems test normal, replace the PAL module.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

Note. Radio systems with the antenna(s) in the glass are subject to possible interference when an aftermarket window tint is applied, especially when there is a metallic present in the film.

Poor AM and FM radio reception is dependent on multiple influences, some of which may not be vehicle related. Areas which have high RF traffic or block the signal path may cause a degradation in radio reception. Radio reception may also be influenced by items within the vehicle, but not part of the radio system. Such examples are aftermarket electrical accessories or other items which may generate noise in the vehicle electrical system.

AM reception is highly dependent on the antenna module receiving battery voltage from the radio and being properly grounded. The antenna module has a built in antenna amplifier that boosts both AM and FM reception. When the antenna module does not receive power, AM stations will not be received and FM reception will be limited. If the module is not properly grounded, excessive interference in the signal may occur, or reception may be limited.

Rear Glass Antenna Testing

1. Inspect the antenna on the rear glass. Verify all branches of the antenna are intact, with no scratches or other damage. If damage is found, repair or replace as necessary.
2. Verify the connector at the back glass is properly secured and free of any damage. If damage is found, repair or replace as necessary.
3. Inspect the radio antenna module grounding surfaces and the mounting hardware for any corrosion that may cause a poor ground. If corrosion is noted, clean the grounding surfaces or hardware.
4. Ignition OFF, disconnect the harness connector at the radio antenna module.
5. Ignition ON, radio ON, test for B+ between the signal circuit terminal 1 and ground. If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
6. Disconnect the antenna coax from the radio and the radio antenna module.
7. Test for infinite resistance between the antenna coax center terminal and ground. If less than the specified value, replace the antenna coax.
8. Test for infinite resistance between the coax center terminal and the outer shield. If less than the specified value, replace the antenna coax.
9. Test for less than 5 ohms on the antenna coax center terminal from end to end. If greater than the specified value, replace the antenna coax.
10. Test for less than 5 ohms on the antenna coax outer shield from end to end. If greater than the specified value, replace the antenna coax.
11. If all circuits test normal, replace the antenna module. Reconnect the antenna coax.
12. Ignition ON, radio ON, verify radio reception has improved. If reception is still poor, replace the radio.

Fixed Mast Antenna Testing

1. Ignition OFF, disconnect the radio antenna coax cable from the radio and the radio antenna.
2. Test for infinite resistance between the antenna coax center terminal and ground. If less than the specified value, replace the antenna coax.
3. Test for infinite resistance between the coax center terminal and the outer shield. If less than the specified value, replace the antenna coax.
4. Test for less than 5 ohms on the antenna coax center terminal from end to end. If greater than the specified range, replace the antenna coax.
5. Test for less than 5 ohms on the antenna coax outer shield from end to end. If greater than the specified range, replace the antenna coax.
6. Reconnect the coax to the radio antenna. Test for infinite resistance on the coax at the radio between the center terminal and the outer shield. If less then specified value, replace the antenna.
7. Test for less than 10 ohms on the coax at the radio between the outer shield and ground. If greater than specified value, clean the mounting surface of the antenna ground plane. If no corrosion found, replace the antenna.
8. If all circuits test normal, replace the radio.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provide an overview of each diagnostic category.

1. Improper speaker mounting or loose trim may cause an audible buzz or distortion. Inspect the appropriate speaker and the surrounding interior trim for proper and secure mounting. If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.
2. When equipped with an amplifier, it is possible for some individual circuit faults to affect more than one speakers operation. Perform diagnostic tests in the sequence listed to avoid misdiagnosis.
3. The front tweeter speakers are connected to the same channel as the front door speakers.

Speaker Circuit Malfunction - without Amplifier

1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
4. If all circuits test normal, replace the speaker.

Amplifier Circuit Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the audio amplifier.
2. Ignition OFF, test for less than 10 ohms between the ground circuit terminal 8 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for B+ between the B+ circuit terminal 4 and ground. If less then specified value, test the circuit for a short to ground, or an open/high resistance.
4. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
5. For vehicles without RPO code Y91 only: Radio ON, test for B+ between the remote enable signal circuit terminal 8 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
6. If all circuits test normal, replace the audio amplifier.

Speaker Malfunction Radio Output Testing UQA

1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 15 Left front low level audio signal (-) - terminal 7 Right front low level audio signal (+) - terminal 14 Right front low level audio signal (-) - terminal 6 Left rear low level audio signal (+) - terminal 13 Left rear low level audio signal (-) - terminal 5 Right rear low level audio signal (+) - terminal 12 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the audio amplifier.

Speaker Malfunction Radio Output Testing UQS or UQA with Y91

1. Ignition OFF, disconnect the X3 and X4 harness connectors at the audio amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 11 X3 Left front low level audio signal (-) - terminal 12 X3 Right front low level audio signal (+) - terminal 3 X3 Right front low level audio signal (-) - terminal 4 X3 Left rear low level audio signal (+) - terminal 11 X4 Left rear low level audio signal (-) - terminal 12 X4 Right rear low level audio signal (+) - terminal 3 X4 Right rear low level audio signal (-) - terminal 4 X4 Subwoofer low level audio signal (+) - terminal 5 X4 Subwoofer low level audio signal (-) - terminal 6 X4 Center Channel low level audio signal (+) - terminal 13 X4 Center Channel low level audio signal (-) - terminal 14 X4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the audio amplifier.

Speaker Malfunction Radio Output Testing UQA with U42

1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 15 Left front low level audio signal (-) - terminal 7 Right front low level audio signal (+) - terminal 14 Right front low level audio signal (-) - terminal 6 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. Ignition OFF, reconnect the X3 harness connector at the audio amplifier.
4. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 1 Left rear low level audio signal (-) - terminal 2 Right rear low level audio signal (+) - terminal 3 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
6. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
7. Disconnect the X3 harness connector at the audio amplifier.
8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 13 Left rear low level audio signal (-) - terminal 5 Right rear low level audio signal (+) - terminal 12 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
9. If all circuits test normal, replace the audio amplifier.

Speaker Malfunction Radio Output Testing UQA with Y91 or UQS

1. Ignition OFF, disconnect the X3 and X4 harness connectors at the audio amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 11 X3 Left front low level audio signal (-) - terminal 12 X3 Right front low level audio signal (+) - terminal 3 X3 Right front low level audio signal (-) - terminal 4 X3 Left rear low level audio signal (+) - terminal 11 X4 Left rear low level audio signal (-) - terminal 12 X4 Right rear low level audio signal (+) - terminal 3 X4 Right rear low level audio signal (-) - terminal 4 X4 Subwoofer low level audio signal (+) - terminal 5 X4 Subwoofer low level audio signal (-) - terminal 6 X4 Center Channel low level audio signal (+) - terminal 13 X4 Center Channel low level audio signal (-) - terminal 14 X4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. If all circuits test normal, replace the audio amplifier.

Speaker Malfunction Radio Output Testing UQA with Y91 and with U42 or UQS with U42

1. Ignition OFF, disconnect the X3 and X4 harness connector at the audio amplifier.
2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left front low level audio signal (+) - terminal 11 X3 Left front low level audio signal (-) - terminal 12 X3 Right front low level audio signal (+) - terminal 3 X3 Right front low level audio signal (-) - terminal 4 X3 Subwoofer low level audio signal (+) - terminal 5 X4 Subwoofer low level audio signal (-) - terminal 6 X4 Center Channel low level audio signal (+) - terminal 13 X4 Center Channel low level audio signal (-) - terminal 14 X4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
3. Ignition OFF, reconnect the X3 harness connector at the audio amplifier.
4. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 1 Left rear low level audio signal (-) - terminal 2 Right rear low level audio signal (+) - terminal 3 Right rear low level audio signal (-) - terminal 4 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
6. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
7. Disconnect the X2 harness connector at the audio amplifier.
8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground. Left rear low level audio signal (+) - terminal 15 Left rear low level audio signal (-) - terminal 14 Right rear low level audio signal (+) - terminal 16 Right rear low level audio signal (-) - terminal 8 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
9. If all circuits test normal, replace the audio amplifier.

Speaker Malfunction Amplifier Output Testing UQA

1. Ignition OFF, disconnect the X1 and X2 connectors at the audio amplifier.
2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 3 X2 Right front speaker output (+) - terminal 2 X2 Right front low speaker output (-) - terminal 1 X2 Left rear speaker output (+) - terminal 8 X2 Left rear speaker output (-) - terminal 7 X2 Right rear speaker output (+) - terminal 6 X2 Right rear speaker output (-) - terminal 5 X2 Left or rear subwoofer speaker output (+) - terminal 7 X1 Left or rear subwoofer speaker output (-) - terminal 3 X1 Right subwoofer speaker output (+) - terminal 6 X1 Right subwoofer speaker output (-) - terminal 2 X1 If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 3 X2 Right front speaker output (+) - terminal 2 X2 Right front low speaker output (-) - terminal 1 X2 Left rear speaker output (+) - terminal 8 X2 Left rear speaker output (-) - terminal 7 X2 Right rear speaker output (+) - terminal 6 X2 Right rear speaker output (-) - terminal 5 X2 Left or rear subwoofer speaker output (+) - terminal 7 X1 Left or rear subwoofer speaker output (-) - terminal 3 X1 Right subwoofer speaker output (+) - terminal 6 X1 Right subwoofer speaker output (-) - terminal 2 X1 If less than the specified range, test both circuits of the affected speaker for a short to ground.
4. If all circuits test normal, reconnect all harness connectors at the audio amplifier.
5. Radio ON, disconnect the appropriate speaker.
6. Test for 5.0-7.5 volts between the signal circuit terminals and ground. If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the amplifier. If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier.
7. If the circuit tests normal, replace the appropriate speaker.

Speaker Malfunction Amplifier Output Testing UQA with Y91 or UQS

1. Ignition OFF, disconnect the X1 and X2 connectors at the audio amplifier.
2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 5 X2 Right front speaker output (+) - terminal 7 X2 Right front speaker output (-) - terminal 6 X2 Left rear speaker output (+) - terminal 15 X2 Left rear speaker output (-) - terminal 14 X2 Right rear speaker output (+) - terminal 16 X2 Right rear speaker output (-) - terminal 8 X2 Front center speaker output (+) - terminal 13 X2 Front center speaker output (-) - terminal 12 X2 Right rear midrange speaker output (+) - terminal 3 X2 Right rear midrange speaker output (-) - terminal 2 X2 Left rear midrange speaker output (+) - terminal 11 X2 Left rear midrange speaker output (-) - terminal 10 X2 Left or rear subwoofer speaker output (+) - terminal 1 X1 Left or rear subwoofer speaker output (-) - terminal 2 X1 Right subwoofer speaker output (+) - terminal 7 X1 Right subwoofer speaker output (-) - terminal 3 X1 If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground: Left front speaker output (+) - terminal 4 X2 Left front speaker output (-) - terminal 5 X2 Right front speaker output (+) - terminal 7 X2 Right front speaker output (-) - terminal 6 X2 Left rear speaker output (+) - terminal 15 X2 Left rear speaker output (-) - terminal 14 X2 Right rear speaker output (+) - terminal 16 X2 Right rear speaker output (-) - terminal 8 X2 Front center speaker output (+) - terminal 13 X2 Front center speaker output (-) - terminal 12 X2 Right rear midrange speaker output (+) - terminal 3 X2 Right rear midrange speaker output (-) - terminal 2 X2 Left rear midrange speaker output (+) - terminal 11 X2 Left rear midrange speaker output (-) - terminal 10 X2 Left or rear subwoofer speaker output (+) - terminal 1 X1 Left or rear subwoofer speaker output (-) - terminal 2 X1 Right subwoofer speaker output (+) - terminal 7 X1 Right subwoofer speaker output (-) - terminal 3 X1 If less than the specified range, test both circuits of the affected speaker for a short to ground.
4. If all circuits test normal, reconnect all harness connectors at the audio amplifier.
5. Radio ON, disconnect the appropriate speaker.
6. Test for 5.0-7.5 volts between the signal circuit terminals and ground. If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the audio amplifier. If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier.
7. If the circuit tests normal, replace the appropriate speaker.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

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 customers 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.
4. It is important to have the vehicle in an open outside area where a cellular call can be successfully placed and GPS data can be received from satellites.

1. Ignition OFF, disconnect both the GPS and cell coax cable connectors at the K73 telematics communication interface control module.
2. Connect the EL-49903 to the K73 telematics communication interface control module, place the test antenna on the roof of the vehicle. See «Special Tools»(ref-364479-S40951042282010063000000) .
3. Ignition ON, wait 5 minutes, and then contact the OnStar call center consultant by pressing the blue OnStar button. A call center consultant should answer the call. If the unit does not connect to the OnStar Call Center and the subscription is valid, use a scan tool to obtain and record the following information: Electronic Serial Number (ESN), Station Identifier (STID), GM 8-digit part number, Mobile Identification Number (MIN), Mobile Dialed Number (MDN), Transceiver ID (Trans ID) and call GM TAC.
4. Request the consultant to verify the vehicle location to confirm the GPS system is functioning. If the OnStar GPS does not function, replace the K73 telematics communication interface module.
5. Ignition OFF, perform the coax cable test on the coax cable, refer to Component Testing. The coax cable should pass the test. If the coax cable does not pass the test, replace the coax cable.
6. If all circuits test normal, replace the T4 cellular phone and navigation antenna.

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 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 GPS and cellular phone coax cable at both components.
2. Test both for less than 5 ohms between both ends of the coax cables center terminals. If greater than the specified range, replace the failed coax cable.
3. Test for greater than 10k ohms between the coax cable center wire and the outer coax shield. If less than the specified range, replace the coax cable.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The rear seat entertainment (RSE) system utilizes the vehicle radio to play DVD movies and transmit video signals to the rear digital video disc (DVD) display. When the radio is turned ON, the DVD display receives a voltage signal from the radio via the entertainment remote enable signal circuit indicating the system status. The video high and low signal circuits are used to transmit the DVD images to the rear DVD display. The video high (+) voltage will vary as the brightness and the speed of the image varies. A typical voltage reading for the video high (+) is 1 to 2.5V at the disconnected at the video display.

1. Ignition OFF, disconnect the harness connector at the appropriate DVD display.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminals listed below and ground. Ground terminal 6 Ground terminal 5 (DNU) If greater than specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, DVD playing, test for B+ between the entertainment remote enable B+ circuit terminal 8 and ground. If less than specified value, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
4. Ignition ON, test for B+ between the battery positive voltage circuit terminal 7 and ground. If less than specified value, test the voltage supply circuit for a short to ground or an open/high resistance.
5. Ignition ON, DVD playing, test for 1-8 volts between the video bright control circuit terminal 9, and ground. If greater then specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the radio. If less then specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
6. Ignition ON, DVD playing, test for 0.1-3.0 volts between the video mode signal circuit terminal 10, and ground. If greater then specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio. If less then specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
7. Ignition ON, DVD playing, test for 1-3 volts between the video signal (+) circuit terminal 1, and ground. If greater then specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the radio. If less then specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
8. If all circuits test normal, replace the DVD display.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The rear seat entertainment (RSE) system utilizes the vehicle radio to play DVD movies and transmit video signals to the rear digital video disc (DVD) display. When the radio is turned ON, the DVD display receives a voltage signal from the radio via the entertainment remote enable signal circuit indicating the system status. The video high and low signal circuits are used to transmit the DVD images to the rear DVD display. The video high (+) voltage will vary as the brightness and the speed of the image varies. A typical voltage reading for the video high (+) is 1 to 2.5V at the disconnected at the video display.

1. Ignition OFF, disconnect the harness connector at the appropriate DVD display.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminals listed below and ground. Ground terminal 6 Ground terminal 5 (DNU) If greater than specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, DVD playing, test for B+ between the entertainment remote enable B+ circuit terminal 8 and ground. If less than specified value, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
4. Ignition ON, test for B+ between the battery positive voltage circuit terminal 7 and ground. If less than specified value, test the voltage supply circuit for a short to ground or an open/high resistance.
5. Ignition ON, DVD playing, test for 1-8 volts between the video bright control circuit terminal 9, and ground. If greater then specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the radio. If less then specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
6. Ignition ON, DVD playing, test for 0.1-3.0 volts between the video mode signal circuit terminal 10, and ground. If greater then specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio. If less then specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
7. Ignition ON, DVD playing, test for 1-3 volts between the video signal (+) circuit terminal 1, and ground. If greater then specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the radio. If less then specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
8. If all circuits test normal, replace the DVD display.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The infrared transmitter is grounded and powered by the rear seat audio (RSA) module. When a key on the remote is pressed, the remote control sends an infrared message to infrared transmitter. The infrared transmitter will convert these infrared signals into a frequency and send that message to the radio via the remote infrared signal circuits (+) and (-).

Note. Test or replace the remote batteries before performing the circuit/system test.

1. Ignition OFF, disconnect the harness connector at the infrared transmitter.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal 12 and ground. If greater than specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, DVD playing, test for B+ between the infra red module control circuit terminal 4 and ground. If less than specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio module.
4. Ignition ON, DVD playing, test for 0.75-2 volts between the remote infra red signal (+) circuit and ground. If less than specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
5. Ignition ON, DVD playing, test for less than 1 volt between the remote infra red signal (-) circuit and ground. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
6. Reconnect the harness connector at the infrared transmitter, and disconnect the X3 harness connector at the radio.
7. Ignition ON, DVD playing, test for 4-6 mV AC between the remote infra red signal (+) circuit and ground. If less than specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the infrared transmitter. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the infrared transmitter.
8. Ignition ON, DVD playing, test for 4-6 mV AC between the remote infra red signal (-) circuit and ground. If less than specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the infrared transmitter. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the infrared transmitter.
9. Ignition ON, DVD playing, press any button on the remote control aimed at the infrared transmitter and test for 300-330 MHz between the remote infra red signal (+) circuit and ground. If not within the specified range, replace the remote control.
10. If all circuits test normal, replace the radio.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

The infrared transmitter is grounded and powered by the rear seat audio (RSA) module. When listening to the headphones, the infrared transmitter sends an infrared signal to the headphones. There are two channels on the headphones, channel 1 is dedicated to the video screen, and channel 2 is dedicated to the rear seat audio (RSA). The audio that is sent over the DVD and rear seat audio signal circuits is a varying AC voltage.

1. Ignition OFF, disconnect the harness connector at the infrared transmitter.
2. Test for less than 5.0 ohms between the ground circuit terminal 12 and ground. If greater than specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, DVD playing, test for B+ between the infra red module control circuit terminal 4 and ground. If less than specified value, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio module.
4. Ignition ON, DVD playing, test for AC voltage between the following signal circuit terminals listed below and ground. Left DVD audio signal (+) - terminal 1 DVD audio common (-) - terminal 2 Right DVD audio signal (+) - terminal 3 If AC voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the radio.
5. Ignition ON, RSA ON, test for AC voltage between the following signal circuit terminals listed below and ground. Left infra red audio signal (+) - terminal 9 Infra red audio low reference (-) - terminal 10 Right infra red audio signal (+) - terminal 11 If AC voltage is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the RSA.
6. If all circuits test normal, test or replace the infrared transmitter.

1. Perform the «Diagnostic System Check - Vehicle»(ref-364486-S08087544882010063000000) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(ref-364486-S25727745392010063000000) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(ref-364486-S17107648382010063000000) provides an overview of each diagnostic category.

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 GPS.

The cellular operation of the OnStar® system may be inhibited by factors such as the users range from an analog or digital cellular tower, the state of the cellular carrier's equipment, and the location where the call is placed. Making an OnStar® key press 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, electronic serial number or manufacturers electronic ID, are not recognized by the cellular carriers local signal receiving towers.

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.