Audio System with Navigation: Diagnosis Saab 9-4X I

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.

Diagnostic Instructions

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC Descriptor

DTC B0000 5A

Vehicle Speed Information Circuit Not Plausible

Diagnostic Fault Information

Conditions for Running the DTC

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

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 will be cleared after 100 malfunction-free ignition cycles.

Scan Tool Reference

CONTROL MODULE REFERENCES for scan tool information

Circuit/System Testing

Note. Diagnose any antilock brake system (ABS) related DTCs before performing this diagnostic.

1. Ignition OFF, disconnect the X4 harness connector at the A11 Radio.
2. Ignition ON, operate the vehicle drive wheels at 5 mph. Test for 3-7 Hertz between the signal circuit terminal 20 and ground.
3. If not within the specified range, test the signal circuit terminal 20 for an open, high resistance, short to ground or short to voltage. If the circuit tests normal replace the K17 EBCM.
4. If the circuit tests normal, replace the A11 radio.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B1020 00

Auxiliary Electronic Control Unit (ECU) Performance

1. Ignition is ON or in the ACC position.
2. The system voltage is at least 9.5 V and no more than 15.5 V.
3. All the above conditions are present for greater than 10 seconds.

The radio receives an improper status response indicating an internal ECU fault in the radio/HVAC control.

No action is taken.

1. A current DTC clears when the radio receives a proper status response message back from the radio control assembly.
2. A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

1. This DTC may be stored as a history DTC without affecting the operation of the radio/HVAC control.
2. If stored only as a history DTC and not retrieved as a current DTC, do not replace the radio/HVAC control.
3. If this DTC is retrieved as both a current and history DTC, replace the radio/HVAC control.

CONTROL MODULE REFERENCES for scan tool information

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC Descriptors

DTC B1025 01

Left Front Audio Output Circuit Short to Battery

DTC B1025 02

Left Front Audio Output Circuit Short to Ground

DTC B1025 04

Left Front Audio Output Circuit Open

DTC B1035 01

Front Audio Output Circuit Short to Battery

DTC B1035 02

Right Front Audio Output Circuit Short to Ground

DTC B1035 04

Right Front Audio Output Circuit Open

DTC B1045 01

Left Rear Audio Output Circuit Short to Battery

DTC B1045 02

Left Rear Audio Output Circuit Short to Ground

DTC B1045 04

Left Rear Audio Output Circuit Open

DTC B1055 01

Right Rear Audio Output Circuit Short to Battery

DTC B1055 02

Right Rear Audio Output Circuit Short to Ground

DTC B1055 04

Right Rear Audio Output Circuit Open

Diagnostic help

Incorrect speaker installation or loose trim can cause audible buzzing or distortion.

Inspect relevant speaker and surrounding trim. Faults in fit and installation must be remedied.

1. Ignition in ON or ACC position.
2. The system voltage is 9 - 16 V.
3. The test is run once under radio Wake Up.

B1025 01, B1035 01, B1045 01, B1055 01

The radio detects a short to voltage on the specified audio (+) or (-) circuit.

B1025 02, B1035 02, B1045 02, B1055 02

The radio detects a short to ground on the specified audio (+) or (-) circuit.

B1025 04, B1035 04, B1045 04, B1055 04

The radio detects an open on the specified audio (+) or (-) circuit.

The radio continues to send the output signal to the speaker signal circuit with the current fault.

1. A current DTC clears when the conditions for setting the DTC are no longer present and the ignition has been cycled from OFF to ON.
2. A history DTC clears after 50 malfunction-free ignition cycles.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the appropriate P19 speaker.
2. Radio ON, test for 5.0-7.5 V between the signal circuit terminal 1 and ground.
3. 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 A11 radio.
4. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.
5. Test for 5.0-7.5 V between the signal circuit terminal 2 and ground.
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 A11 radio.
7. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.
8. If all circuits test normal, replace the appropriate P19 speaker.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B125A 02

Antenna Signal Circuit Short to Ground

DTC B125A 04

Antenna Signal Circuit Open Circuit

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

B125A 02

The radio detects a short to ground in the antenna signal circuit center conductor.

B125A 04

The radio detects an open in the antenna signal circuit center conductor.

Radio reception may be poor or not available.

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

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the radio antenna coax from the A11 radio and from the radio antenna.
2. Test for infinite resistance between the antenna coax center terminal and ground.
3. If less than the specified value, replace the antenna coax.
4. Test for less than 5 ohms on the antenna coax center circuit from end to end.
5. If greater than the specified range, replace the antenna coax.
6. Ignition ON, test for less than 1 V between the antenna coax center terminal and ground.
7. If greater than the specified range, replace the antenna coax.
8. Test for infinite resistance between the coax center terminal and the outer shield.
9. If less than the specified value, replace the antenna coax.
10. Connect the antenna coax to the A11 radio. Test for 12-15 V between the antenna coax center terminal and ground at the radio antenna connector.
11. If not within the specified range, replace the A11 radio.
12. If all circuits test normal, replace the radio antenna.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B125C 01

Satellite Antenna 1 Circuit Short to Battery

DTC B125C 02

Satellite Antenna 1 Circuit Short to Ground

DTC B125C 04

Satellite Antenna 1 Circuit Open Circuit

This DTC is run every 300 milliseconds.

The radio detects a circuit fault in the digital radio antenna.

The radio displays No XM Signal or Check Antenna.

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

1. Ignition OFF, disconnect the digital radio antenna coax cable from the A11 radio. Connect the EL-48028 to the radio and place on the roof of the vehicle.
2. Ignition ON, radio tuned to XM channel 1. Verify DTC B125C is not set as current and XM reception is improved.
3. If DTC B125C is set as current or the reception is not improved, replace the radio.
4. Ignition OFF, reconnect the antenna coax cable at the A11 radio. Disconnect the antenna coax cable from the T4G antenna.
5. Ignition ON, radio ON, test for 4.5-5.5 V between the antenna coax cable center terminal and an outer shield.
6. If less than the specified range, test the antenna coax cable for an open/high resistance.
7. If greater than the specified range, test the antenna coax cable for a short to voltage.
8. If all circuits test normal, replace the T4G antenna.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B1265 02

Switched 14 Volt Performance Short to Ground

1. The radio is ON.
2. The system voltage is 9-16 V

1. The radio detects a short to ground on the entertainment remote enable circuit circuit.
2. The above condition is present for greater than 250 mS.

1. The radio implements a current limiting mode and disables the output on the entertainment remote enable circuit.
2. All components connected on the entertainment remote enable circuit will be inoperative.

1. The condition responsible for setting the DTC no longer exists.
2. After the ignition has been OFF for a sufficient amount of time to allow the radio to enter a low power/sleep state, the radio will re-enable the output on the following ignition cycle and the DTC will become history.
3. A history DTC clears after 50 malfunction-free ignition cycles.

1. This DTC may be stored as a history DTC without affecting the operation of the radio/infotainment systems.
2. The radio's current limiting logic will not re-enable the output on the entertainment remote enable circuit until after the radio performs a full power-down. It may be necessary to wait 5 minutes with the key OFF and retained accessory power OFF for the radio to re-enable this output.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, radio OFF, radio B+ fuse removed, disconnect all of the connectors listed below: T3 Audio Amplifier X3 P22D Driver Seatback Video Display (if equipped) P22P Passenger Seatback Video Display (if equipped)
2. Reinstall the radio B+ fuse. Switch on the ignition, switch on the radio and check that a test lamp lights between the entertainment system's remote control activation circuit connections given below and ground: T3 Audio Amplifier X3 terminal 8 P22D Driver Seatback Video Display terminal 2 (if equipped) P22P Passenger Seatback Video Display terminal 2 (if equipped)
3. If the test lamp does not illuminate, test the entertainment remote enable circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the A11 radio.
4. Re-connect the harness connectors listed below one at a time. Verify that DTC B1265 does NOT set as current as each component is re-connected. T3 Audio Amplifier X3 P22D Driver Seatback Video Display (if equipped) P22P Passenger Seatback Video Display (if equipped)
5. If DTC B1265 sets as current, replace the module/component that was just re-connected.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B1271 00

Theft Protection Active

This DTC test runs when the radio changes from OFF to ON.

The radio has learned a correct VIN sequence and the VIN information received via serial data does NOT match the learned VIN sequence.

The radio may be disabled or have limited functionality. The radio display will indicate that theft protection is active.

The radio receives the correct VIN information via serial data.

A possible cause of incorrect VIN info could be the radio was originally installed in another vehicle.

CONTROL MODULE REFERENCES for scan tool information

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B1287 01

Amplifier Control Signal Circuit Short to Battery

DTC B1287 02

Amplifier Control Signal Circuit Short to Ground

DTC B1287 04

Amplifier Control Signal Circuit Open

The following are conditions that must be present in order for the radio to enable the diagnostics.

1. The radio is in ACCESSORY, RUN, or RAP power mode.
2. The system voltage is 9-16 V.
3. The radio performs the test once during radio wakeup.

The radio detects a fault on the amplifier control circuit 400 ms after radio activates the remote enable circuit.

Radio sets the DTC and continues to output correct state.

1. The condition must be corrected.
2. A history DTC will be cleared after 100 malfunction-free ignition cycles.

CONTROL MODULE REFERENCES for scan tool information

1. NOTE: To prevent misdiagnosis, the door chime must be OFF during testing. Ensure the driver door latch is closed during testing. Ignition OFF, disconnect the X3 harness connector at the T3 amplifier.
2. Ignition ON, start the radio, mute ON and test for 7.5 - 8.5 V between amplifier control circuit 11 and ground.
3. 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 A11 radio.
4. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.
5. Mute OFF, test 7.5-8.5 for less than 1V between the amplifier control circuit terminal 11 and ground.
6. If higher than the stated value, replace the radio A11.
7. If all circuits test normal, replace the T3 amplifier.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B1288 01

Video Display Mode Control Signal Short to Battery

DTC B1288 02

Video Display Mode Control Signal Short to Ground

DTC B1288 04

Video Display Mode Control Signal Open Circuit

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.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the appropriate P22 seatback video display.
2. Ignition ON, DVD playing, test for 190-210 HZ DC between the video mode control circuit terminal 15 and ground.
3. 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.
4. If all circuits test normal, replace the P22 rear video display.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B1289 01

Video Display Brightness Control Signal Short to Battery

DTC B1289 02

Video Display Brightness Control Signal Short to Ground

DTC B1289 04

Video Display Brightness Control Signal Open Circuit

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.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connectors at both of the P22 seatback video displays.
2. Ignition ON, DVD playing, test for 190-210 HZ DC between the video brightness control circuit terminal 16 and ground at each of the P22 seatback video displays.
3. 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.
4. Ignition OFF, reconnect the harness connector at the P22E driver seatback video display.
5. Ignition ON, DVD playing, test for 190-210 HZ DC between the video brightness control circuit terminal 16 and ground at the P22F passenger seatback video display.
6. If not within the specified range, replace the P22E driver seatback video display.
7. If all circuits test normal, replace the P22F passenger seatback video display.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B2455 02

Cellular Phone Microphone Circuit Short to Ground

DTC B2455 04

Cellular Phone Microphone Circuit Open

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.
3. All the above conditions are present for greater than 10 seconds.

B2455 02

The telematics communication interface control module detects an short to ground in the cellular phone microphone signal circuit for 10 seconds or greater.

B2455 04

The following conditions will set this DTC

1. The telematics communication interface control module detects an open/high resistance in the cellular phone microphone signal circuit for 10 seconds or greater.
2. The telematics communication interface control module detects an open/high resistance in the low reference circuit for 10 seconds or greater.

1. The OnStar® status LED turns red.
2. The telematics communication interface control module will not receive a signal from the cellular phone 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.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the B24 cellular phone microphone.
2. Ignition ON, test for 9.5-10.5 V between the signal circuit terminal B and ground.
3. If less than the specified range, test the circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
4. If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
5. Test for 9.5-10.5 V between the signal circuit terminal B and the low reference circuit terminal A.
6. If less than the specified range, test the low reference circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
7. If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
8. If all circuit test normal, replace the B24 cellular phone microphone.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B2462 01

Global Positioning System Short to Battery

DTC B2462 02

Global Positioning System Short to Ground

DTC B2462 04

Global Positioning System Open

1. Radio ON.
2. System voltage is greater than 9 V and less than 16 V.
3. The navigation radio tests the GPS antenna every 10 seconds.

B2462 01

Navigation radio registers a short circuit to B+ on the GPS antenna's signal circuit.

B2462 02

Navigation radio registers a short circuit to ground on the GPS antenna's signal circuit.

B2462 04

Navigation radio registers an open circuit/high resistance on the GPS antenna's signal circuit.

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. This DTC can only be obtained from the radio. Telematic module for the communication interface does not generate this DTC.
2. The radio only monitors the connection between the navigation signal's centre conductor and the radio. The radio cannot detect faults between the centre conductor and the navigation antenna. A similar fault results in a lost GPS signal without setting DTC B2462.
3. The navigation antenna needs unrestricted view of the sky to function correctly. The GPS reception is limited/disappears indoors and near high buildings.

CONTROL MODULE REFERENCES for scan tool information

Component Testing

Refer to CAUTION: TEST PROBE .

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 coax cable at both components.
2. Test for less than 5 ohms between both ends of the coax cables center terminals.
3. If greater than the specified range, replace the coax cable
4. Test for less than 5 ohms between both ends of the coax cable outer shield.
5. If greater than the specified range, replace the coax cable
6. Test for infinite resistance between the coax cable center wire and the outer coax shield.
7. If less than the specified range, replace the coax cable.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B2470 02

Cellular Phone Antenna Circuit Malfunction Short to Ground

DTC B2470 04

Cellular Phone Antenna Circuit Malfunction Open Circuit

1. Ignition 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.

The telematics communication interface control module does not detect the presence of a cellular phone antenna.

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

1. The telematics communication interface control module detects the presence of a cellular phone antenna.
2. A history DTC clears after 50 malfunction-free ignition cycles.

CONTROL MODULE REFERENCES for scan tool information

Circuit/System Testing (without Navigation Radio)

Note. The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.

1. Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 telematics communication interface control module.
2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 to the K73 telematics communication interface control module.
3. Clear the DTCs and operate the vehicle within the conditions for running the DTC. Verify DTC B2470 does not set.
4. If the DTC sets, replace the K73 telematics communication interface control module.
5. Ignition OFF, disconnect the EL-49903 from the K73 telematics communication interface control module and perform the coax cable test on the coax cable between the k73 telematics communication interface control module and the T4G cellular phone, navigation, and digital radio antenna.
6. If the coax cable does not pass the test, replace the coax cable.
7. If all circuits test normal, replace the T4G cellular phone, navigation, and digital radio antenna.

Circuit/System Testing (with Navigation Radio)

Note. The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.

1. Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 telematics communication interface control module.
2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 to the K73 telematics communication interface control module.
3. Clear the DTCs and operate the vehicle within the conditions for running the DTC. Verify DTC B2470 does not set.
4. If the DTC sets, replace the K73 telematics communication interface control module.
5. Ignition OFF, reconnect the coax cable to the K73 telematics communication interface module. Disconnect the coax cable from the T15 navigation signal splitter.
6. Ignition ON, test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
7. If not within the specified range, replace the coax cable.
8. Ignition OFF, reconnect the coax cable to the T15 navigation signal splitter. Disconnect the coax cable from the T4G cellular phone, navigation and digital radio antenna.
9. Ignition ON, test for 4.5-5.5 V between the coax cable center conductor and the outer shield.
10. If within the specified range, replace the T4G cellular phone, navigation and digital radio antenna.
11. Ignition OFF, perform the coax cable test on the coax cable between the T15 navigation signal splitter and the T4G cellular phone, navigation and digital radio antenna, refer to «COMPONENT TESTING»(ref-652254-S14656294072014082300000) . The coax cable should pass the test.
12. If the coax cable does not pass the test, replace the coax cable.
13. If the coax cable passes the test, replace the T15 navigation and signal splitter.

Refer to CAUTION: TEST PROBE

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.

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

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B2476 04

Cellular Phone Select Service Switch Open Circuit

DTC B2476 59

Cellular Phone Select Service Switch Stuck Button

DTC B2482 00

Cellular Phone Select Service Switch Range/Performance

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

B2476 04

The telematics communication interface control module detects an open/high resistance on the keypad supply voltage circuit.

B2482 and B2476 59

The telematics communication interface control module detects a valid signal on the keypad signal circuit for longer than 15 seconds. If one of the OnStar® buttons is held or stuck for 15 seconds or greater, the telematics communication interface control module will set this DTC.

1. The OnStar® status LED turns red.
2. No calls can be placed.
3. The telematics communication interface control module will ignore all inputs from the OnStar® button assembly.

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.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the A10 inside rearview mirror.
2. Test for less than 15 ohms between the mirror ground circuit terminal listed below and ground: Terminal 5 (-UVC) Terminal 8 (UVC)
3. If greater than the specified range, test the ground circuit for an open/high resistance.
4. Test for 500-900 ohms between the keypad signal circuit terminal listed below and ground: Terminal 3 (-UVC) Terminal 11 (UVC)
5. If less than the specified range, test the keypad signal circuit for a short to ground. If the circuit tests normal, replace the K73 telematics communication interface control module.
6. If greater than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
7. Ignition ON, test for 9.5-10.5 V between the keypad supply voltage circuit terminal listed below and ground: Terminal 4 (-UVC) Terminal 12 (UVC)
8. 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 K73 telematics communication interface control module.
9. If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
10. Test for less than 1 V between the keypad signal circuit terminal listed below and ground: Terminal 3 (-UVC) Terminal 11 (UVC)
11. If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
12. If all circuits test normal, replace the A10 inside rearview mirror.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

DTC B2485 02

Wireless Communication (BT) Antenna Circuit Short to Ground

DTC B2485 04

Wireless Communication (BT) Antenna Circuit Open

1. The ignition is in OFF, ACCESSORY or RUN position.
2. The system voltage is between 9-16 V.
3. The telematics communication interface control module tests the antenna once every second.

B2485 02

1. The signal voltage is less than 1 V.
2. The above conditions must be met for 500 ms.

B2485 04

1. The signal voltage is greater than 2 V.
2. The above conditions must be met for 500 ms.

Actions Taken When the DTC Sets

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 100 consecutive malfunction-free ignition cycles have occurred.

1. Verify the Bluetooth ® antenna is properly connected to the K73 telematics communication interface control module and is not damaged.
2. If the antenna is disconnected or damaged, repair or replace as necessary.
3. Ignition ON, verify the DTC B2485 is not set.
4. 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 K73 telematics communication interface control module.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the radio/audio system. Refer to «CHECKING AFTERMARKET ACCESSORIES»(ref-652238-S27245169932014082300000) .
2. Inspect for easily accessible or visible system components for obvious damage or conditions which may 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-652254-S34669210552014082300000)
2. «NO GLOBAL POSITIONING SYSTEM (GPS) RECEPTION»(ref-652254-S18340836992014082300000)
3. «ONSTAR MICROPHONE MALFUNCTION»(ref-652254-S20781691302014082300000)
4. «ONSTAR AUDIO MALFUNCTION»(ref-652254-S10361760712014082300000)
5. «ONSTAR BUTTON LED MALFUNCTION»(ref-652254-S13910323522014082300000)
6. «ONSTAR CALL CENTER REMOTE FUNCTION REQUESTS MALFUNCTION»(ref-652254-S32457433632014082300000)
7. «ONSTAR BUTTON MALFUNCTION»(ref-652254-S09878779662014082300000)
8. «UNABLE TO CONTACT ONSTAR CALL CENTER»(ref-652254-S00524415652014082300000)
9. «ONSTAR VOICE RECOGNITION MALFUNCTION»(ref-652254-S10089625602014082300000)
10. «ONSTAR STEERING WHEEL CONTROL FUNCTIONS MALFUNCTION»(ref-652254-S08506652672014082300000)

Symptoms - Entertainment

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) 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 the system operation in order to familiarize yourself with the system functions. Refer to «RADIO/AUDIO SYSTEM DESCRIPTION AND OPERATION»(ref-652254-S32594284792014082300000) .

1. Inspect for aftermarket devices which could affect the operation of the radio/audio system. Refer to «CHECKING AFTERMARKET ACCESSORIES»(ref-652238-S27245169932014082300000) .
2. Inspect for easily accessible or visible system components for obvious damage or conditions which may cause the symptom.

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

1. «AUDIO/VIDEO PLAYER ADAPTER - AUDIO OR VIDEO MALFUNCTION»(ref-652254-S37197803162014082300000)
2. «DIGITAL RADIO POOR OR NO RECEPTION»(ref-652254-S39257746432014082300000)
3. «NO GLOBAL POSITIONING SYSTEM (GPS) RECEPTION»(ref-652254-S18340836992014082300000)
4. «RADIO CONTROLS, FUNCTION INTERFERENCE (WITH COLOUR DISPLAY)»(ref-652254-S16555480182014082300000) «RADIO CONTROLS, FUNCTION INTERFERENCE (WITH MONOCHROME DISPLAY)»(ref-652254-S28936316622014082300000)
5. «RADIO INFORMATION DISPLAY, FUNCTION DISTURBANCE - DTC U0257 (WITH COLOUR DISPLAY)»(ref-652254-S03079390892014082300000) «RADIO INFORMATION DISPLAY, FUNCTION DISTURBANCE - DTC U0257 (WITH MONOCHROME DISPLAY)»(ref-652254-S13627764352014082300000)
6. «RADIO POOR RECEPTION»(ref-652254-S11767975882014082300000)
7. «SPEAKER MALFUNCTION»(ref-652254-S40378103902014082300000)
8. «VIDEO ENTERTAINMENT SYSTEM MALFUNCTION»(ref-652254-S37126491512014082300000)
9. «VIDEO ENTERTAINMENT SYSTEM REMOTE CONTROL MALFUNCTION»(ref-652254-S28810636932014082300000)
10. «VIDEO ENTERTAINMENT SYSTEM WIRELESS HEADPHONE MALFUNCTION»(ref-652254-S14191479502014082300000)

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

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

CONTROL MODULE REFERENCES for scan tool information

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
3. If greater then specified range, test the circuit for a short to voltage.
4. 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
5. If less then the specified value, test the circuit for a short to ground.
6. 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
7. If greater then the specified value, test the circuit for an open/high resistance. If the circuit tests normal, replace the adaptor.
8. If all circuits test normal, replace the radio.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

1. The purpose of this diagnostic is to verify the ability of the telematics communication interface control module 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.

CONTROL MODULE REFERENCES for scan tool information

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the digital radio antenna coax from the radio. Connect the EL-48028 to the radio and place on the roof of the vehicle. Move the vehicle outside in an area with an unobstructed view of the southern sky.
2. Ignition ON, radio tuned to XM channel 1, verify XM reception is clear and uninterrupted.
3. If reception is not clear, replace the radio.
4. Ignition OFF, reconnect the antenna coax cable at the radio. Disconnect the antenna coax cable from the digital radio antenna.
5. Ignition ON, radio ON, test for 4.5-5.5 V between the antenna coax cable center terminal and outer shield.
6. If less than the specified range, test the antenna coax cable for an open/high resistance.
7. If greater than the specified range, test the antenna coax cable for a short to voltage.
8. If all circuits test normal, replace the digital radio antenna.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the B24 cellular phone microphone.
2. Ignition ON, test for 9.5-10.5 V between the signal circuit terminal B and ground.
3. If less than the specified range, test the circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
4. If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
5. Test for 9.5-10.5 V between the signal circuit terminal B and the low reference circuit terminal A.
6. If less than the specified range, test the low reference circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
7. If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
8. If all circuit test normal, replace the B24 cellular phone microphone.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the X1 harness connector at the radio.
2. Disconnect the X2 harness connector at the K73 telematics communication interface control module.
3. Ignition ON, test for less than 1 V between the K73 telematics communication interface control module cellular telephone voice signal circuit terminal 1 X2 and ground.
4. If not the specified value, test the cellular telephone voice signal circuit for a short to voltage.
5. Test for less than 1 V between the K73 telematics communication interface control module cellular telephone voice low reference circuit terminal 2 X2 and ground.
6. If not the specified value, test the cellular telephone voice low reference circuit for a short to voltage.
7. Ignition OFF, test for infinite resistance between the K73 telematics communication interface control module cellular telephone voice signal circuit terminal 1 X2 and ground.
8. If not the specified value, test the cellular telephone voice signal circuit for a short to ground.
9. Test for infinite resistance between the K73 telematics communication interface control module cellular telephone voice low reference circuit terminal 2 X2 and ground.
10. If not the specified value, test the cellular telephone voice low reference circuit for a short to ground.
11. Test for less than 2 ohms between the K73 telematics communication interface control module cellular telephone voice signal circuit terminal 1 X2 and the radio terminal 20 X1.
12. If not the specified value, test the cellular telephone voice signal circuit for a open/high resistance.
13. Test for less than 2 ohms between the K73 telematics communication interface control module cellular telephone voice low reference circuit terminal 2 X2 and the radio terminal 6 X1.
14. If not the specified value, test the cellular telephone voice low reference circuit for a open/high resistance.
15. If all circuits test normal, replace the K73 telematics communication interface control module.
16. If all circuits test normal, replace the radio.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

1. The telematics communication interface control module GPS signal title on the scan tool will display a Yes or No dependent upon whether or not the module sees an increment of the seconds transmitted by GPS signals to the telematics communication interface control module. Upon entering this screen, the GPS signal title will initially 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 tunnels or parking structures will restrict the cellular phone and navigation antenna from a clear view of the satellites in the sky and may have caused this temporary data loss.
3. 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.

CONTROL MODULE REFERENCES for scan tool information

Refer to CAUTION: TEST PROBE

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.

1. Ignition OFF, disconnect the coax cable at both components.
2. Test for less than 5 ohms between both ends of the coax cables center terminals.
3. If greater than the specified range, replace the coax cable
4. Test for less than 5 ohms between both ends of the coax cable outer shield.
5. If greater than the specified range, replace the coax cable
6. Test for infinite resistance between the coax cable center wire and the outer coax shield.
7. If less than the specified range, replace the coax cable.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

Circuit Description

The OnStar® status LEDs are located in the inside rear view mirror telematic button assembly. 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 telematics communication interface control module via the keypad green LED control circuit and the keypad red LED control circuit.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the A10 inside rear view mirror.
2. Test for less than 10 ohms between the appropriate ground circuit terminal listed below and ground: Terminal 5 (-UVC) Terminal 8 (UVC)
3. If greater than the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, command the green LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal listed below and ground: Terminal 6 (-UVC) Terminal 14 (UVC)
5. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
6. Command the green LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal listed below and ground: Terminal 6 (-UVC) Terminal 14 (UVC)
7. 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 K73 telematics communication interface control module.
8. Command the red LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal listed below and ground: Terminal 7 (-UVC) Terminal 15 (UVC)
9. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
10. Command the red LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal listed below and ground: Terminal 7 (-UVC) Terminal 15 (UVC)
11. 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 K73 telematics communication interface control module.
12. If all circuits test normal, replace the A10 inside rear view mirror.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) 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.

CONTROL MODULE REFERENCES for scan tool information

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the A10 inside rearview mirror.
2. Test for less than 10 ohms between the appropriate ground circuit terminal listed below and ground: Terminal 5 (-UVC) Terminal 8 (UVC)
3. If greater than the specified range, test the ground circuit for an open/high resistance.
4. Test for 500-900 ohms between the appropriate signal circuit terminal listed below and ground: Terminal 3 (-UVC) Terminal 11 (UVC)
5. If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K73 telematics communication interface control module.
6. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
7. Ignition ON, test for less than 1 V between the signal circuit listed below and ground. Terminal 3 (-UVC) Terminal 11 (UVC)
8. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
9. Test for 8.5-10.5 V between the appropriate 10 V reference circuit terminal listed below and ground: Terminal 4 (-UVC) Terminal 12 (UVC)
10. If less than the specified range, test the 10 V reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
11. If greater than the specified range, test the 10 V reference circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
12. If all circuits test normal, test or replace the A10 rearview mirror.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

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 generated noise in the vehicle electrical system.

AM reception is highly dependent on the antenna receiving battery voltage from the radio. The antenna has a built in antenna amplifier that boosts both AM and FM reception. If the antenna does not receive battery voltage, the radio will still receive FM stations but AM stations will not be received.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the radio antenna coax from the A11 radio and from the radio antenna.
2. Test for infinite resistance between the antenna coax center terminal and ground.
3. If less than the specified value, replace the antenna coax.
4. Test for less than 5 ohms on the antenna coax center circuit from end to end.
5. If greater than the specified range, replace the antenna coax.
6. Ignition ON, test for less than 1 V between the antenna coax center terminal and ground.
7. If greater than the specified range, replace the antenna coax.
8. Test for infinite resistance between the coax center terminal and the outer shield.
9. If less than the specified value, replace the antenna coax.
10. Connect the antenna coax to the A11 radio. Test for 12-15 V between the antenna coax center terminal and ground at the radio antenna connector.
11. If not within the specified range, replace the A11 radio.
12. If all circuits test normal, replace the radio antenna.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides 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 amplifier control circuit will measure less than 1 V when the mute function is OFF, and approximately 8 V DC when at full mute. When mute is active, the radio stops sending the varying AC voltage to the amplifier/speakers.

CONTROL MODULE REFERENCES for scan tool information

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) 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.

CONTROL MODULE REFERENCES for scan tool information

Note. The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.

1. Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 telematics communication interface control module.
2. Using the EL-49903-3 kit (EL-499035 adapter and EL-49903-4 coax cable), connect the EL-49903 to the K73 telematics communication interface control module.
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.
4. If the unit does not connect to the OnStar Call Center, replace the K73 telematics communication interface module.
5. Ignition OFF, disconnect the EL-49903 from the K73 telematics communication interface control module and perform the coax cable test on the coax cable between the K73 telematics communication interface control module and the T4G cellular phone, navigation, and digital radio antenna.
6. If the coax cable does not pass the test, replace the coax cable.
7. If all circuits test normal, replace the T4G cellular phone and navigation antenna.

Note. The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.

1. Ignition OFF, disconnect the GPS and cellular coax cable connector at the K73 telematics communication interface control module.
2. Using the EL-49903-3 kit (EL-49903-5 adapter and EL-49903-4 coax cable), connect the EL-49903 to the K73 telematics communication interface control module.
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.
4. If the unit does not connect to the OnStar Call Center, replace the K73 telematics communication interface module.
5. Ignition OFF, disconnect the EL-49903 from the K73 telematics communication interface control module and perform the coax cable test on the coax cable between the K73 telematics communication interface control module and the T15 navigation antenna signal splitter.
6. If the coax cable does not pass the test, replace the coax cable.
7. Perform the coax cable test on the coax cable between the T15 navigation antenna signal splitter and the T4G cellular phone, navigation, and digital radio antenna.
8. If the coax cable does not pass the test, replace the coax cable.
9. If all coax cables pass the test, replace the T15 navigation antenna signal splitter, 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.
10. If the unit does not connect to the OnStar Call Center, replace the T4G cellular phone, navigation, and digital radio antenna.

Refer to CAUTION: TEST PROBE .

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.

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.
3. If greater than the specified range, replace the failed coax cable.
4. Test for greater than 10k ohms between the coax cable center wire and the outer coax shield.
5. If less than the specified range, replace the coax cable.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) 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 digital video disc (DVD) seatback displays. When the radio is turned ON, the DVD seatback displays receive a voltage signal from the radio via the remote enable signal circuit indicating the system status. Discreet output circuits from the radio are used to transmit the DVD images to each of the DVD seatback displays. The radio utilizes discreet mode control circuits to each display to control the screen display mode via a pulse width modulated signal. A single brightness control circuit is used by the radio to control the display screen brightness for both displays via a pulse width modulated signal.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the appropriate DVD display.
2. Test for less than 10 ohms between the ground circuit terminals listed below and ground. Ground terminal 8 Ground terminal 14
3. If greater than the specified range, test the ground circuit for an open/high resistance.
4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
6. Ignition ON, radio ON, verify a test lamp illuminates between the remote enable control circuit terminal 2 and ground.
7. If the test lamp does not illuminate, test the remote enable circuit for a short to ground or an open/high resistance.
8. DVD playing, test for 190-210 HZ DC between the video bright control circuit terminal 16 and ground.
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.
10. Command the rear screen video mode to normal, test for 190-210 HZ DC between the video mode signal circuit terminal 15 and ground.
11. 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.
12. DVD playing, test for 1-3 V between the control circuit terminals listed below and ground. Video Signal (+)- terminal 9 Video Signal (-) - terminal 10
13. If greater then specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the radio.
14. 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.
15. If all circuits test normal, replace the DVD display.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connectors at both of the P22 seatback video displays.
2. Ignition OFF, scan tool disconnected, open driver door, wait two minutes. Test for less than 1 ohms between the infrared remote signal (-) circuits terminal 13 and ground.
3. If greater than the specified range, test the signal (-) circuit for an open/high resistance. If the circuits test normal, replace the A11 radio.
4. Ignition ON, DVD playing, test for 1-4 V between the infrared remote signal (+) circuit terminal 12 and ground.
5. 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 A11 radio.
6. If greater than specified range, test the signal (+) circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.
7. Ignition OFF, reconnect the harness connector at the P22E driver seatback video display.
8. Ignition ON, DVD playing, test for 1-4 V between the infrared remote signal (+) circuit terminal 12 and ground at the P22F passenger seatback video display.
9. If not within the specified range, replace the P22E driver seatback video display.
10. If all circuits test normal, replace the P22F passenger seatback video display.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for scan tool information

1. Ignition OFF, disconnect the harness connector at the P22E driver seatback video display.
2. Ignition OFF, scan tool disconnected, open driver door, wait five minutes, test for 20-25 ohms between the DVD audio low reference signal (-) circuits terminal 5 and ground.
3. If greater than the specified range, test the low reference (-) circuit for an open/high resistance. If the circuits test normal, replace the A11 radio.
4. Ignition ON, DVD playing with audio present, set the DMM to read min/max, test for a varying voltage greater than 50 mV from 10 mV-250 mV AC between the control circuits listed below and ground: Left DVD audio control (+) - terminal 6 Right DVD audio control (-) - terminal 7
5. 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 circuits test normal, replace the A11 radio.
6. If all circuits test normal, replace the headphones. If the headphones are still inoperative, replace the P22E driver seatback video display.

1. Perform the «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) prior to using this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

Diagnostics instructions

1. Carry out «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) before the diagnostic actions have been started.
2. See «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) For an overview of the diagnostics.
3. Instructions for diagnosis procedure supplies an overview of each diagnostic category.

Diagnostic tool Reference

** Control Module Reference ** For diagnostic tool information

Circuit/system test

1. Ignition OFF, disconnect the cable harness at A20 radio/HVAC control.
2. Check for less than 10ohms between ground connection pin 17 and ground.
3. If larger than stated range, test ground point circuit for high resistance.
4. Check for less than 20ohms between data circuit pin 3 and ground.
5. If higher than within stated range, test ground circuit for infinite/high resistance. If the circuit test is normal, replace A11 radio.
6. Check that the test lamp between B+ circuit pin 10 and ground lights.
7. If the test lamp does not light, check B+ circuit after short circuit or infinite/high resistance.
8. Ignition ON, check that there is 2.4-2.75 V between the data circuit pin 1 and ground.
9. If lower than stated range, test ground circuit for infinite/high resistance. If the circuit test is normal, replace A11 radio.
10. If higher than stated range, check for short circuit. If the circuit test is normal, replace A11 radio.
11. Check that there is 2.4-2.75 V between data circuit pin 2 and ground.
12. If lower than stated range, check for short circuit or infinite/high resistance. If the circuit test is normal, replace the A11 radio.
13. If higher than stated range, check for short circuit. If the circuit test is normal, replace the A11 radio.
14. Check that there is less than 1 V between wake-up signal pin 4 and ground.
15. If higher than stated range, check for short circuit. If the circuit test is normal, replace the A11 radio.
16. Check that there is less than 1 V between reset signal pin 5 and ground.
17. If higher than stated range, check for short circuit. If the circuit test is normal, replace the A11 radio.
18. Ignition ON, reconnect the cable harness to A20 radio/HVAC control
19. Disconnect the cable harness X1 for the A11 radio.
20. Install a DMM between monitor signal pin 13 and ground.
21. Ignition ON, check that DMM displays 4.5-5.5 V DC.
22. If lower than stated range, check for short circuit or infinite/high resistance. If the circuit test is normal, replace the A20 radio/HVAC control.
23. If higher than stated range, check for short circuit. If the circuit test is normal, replace the A20 radio/HVAC control.
24. Press the switch on the radio. Check that DMM read off is temporarily below 1 V and returns to 4.5-5.5 V DC each time the switch is pressed
25. If the stated value is not reached, replace the A20 radio/HVAC control.
26. Check that there is 4.5-5.5 V between reset signal pin 27 and ground.
27. If less than the stated range, check for short circuit or infinite/high resistance. If the circuit test is normal, replace the A20 radio/HVAC control.
28. If higher than stated range, check for short circuit. If the circuit test is normal, replace the A20 radio/HVAC control.
29. If all circuit tests are normal, reinstall the A20 radio/HVAC control and reconnect the cable harness.
30. Ignition ON, radio ON, check that the radio/HVAC control's background lighting lights and that all functions function.
31. If the radio/HVAC control still does not work, replace A11 radio.

1. Carry out «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) before you use this diagnostic procedure.
2. See «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. Instructions for diagnosis procedure gives an overview of each diagnostic category.

CONTROL MODULE REFERENCES for information about the diagnostic tool.

1. Ignition OFF, disconnect the cable harness at A20 radio/HVAC controls.
2. Test for less than 10 ohms between the ground circuit terminal 17 and ground.
3. If greater than stated range, test the ground circuit for open/high resistance.
4. Verify that a test lamp illuminates between the B+ circuit terminal 10 and ground
5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or open/high resistance.
6. Ignition ON, test for 2-11.5 V between the data circuit terminal 7 and ground.
7. If less than the stated range, check the data circuit for short circuit to ground or open/high resistance. If the circuit functions normally, replace the P17 module info display.
8. If greater than stated range, test the data circuit for short circuit to voltage. If the circuit functions normally, replace the P17 module info display.
9. If all circuits function normally, replace the A20 radio/HVAC controls.

1. Carry out «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) before you use this diagnostic procedure.
2. Review «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) for an overview of the diagnostic approach.
3. «DIAGNOSTIC PROCEDURE INSTRUCTIONS»(ref-652232-S26410554662014082300000) provides an overview of each diagnostic category.

CONTROL MODULE REFERENCES for diagnostic tool information

Diagnostic instruction

1. Carry out «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) before carrying out this diagnostic procedure.
2. See «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) For an overview of the diagnostic procedure.
3. Instructions for diagnosis procedure gives an overview of each diagnostic category.

Scan Tool References

See Control module, references for information about the diagnostic tool.

1. Ignition switch OFF, check that video interface cable is properly connected to screen X2 and radio X5 connections and that there is no damage to the cable or connections.
2. Carry out suitable repair actions or replacement to correct any faults with the video interface cable or its connections.
3. Ignition switch OFF, disconnect connector X1 from K31 navigation module.
4. Test for less than 10 ohms between the ground circuit connection and ground.
5. If higher value, check if ground has open/has high resistance.
6. Check for less than 20ohms between data circuit pin 7 and ground.
7. If higher value, check if ground has open/has high resistance. If the circuit tests OK, replace the A11 radio.
8. Check with a test lamp between B+ pin 1 and ground.
9. If the test lamp does not light, check if the B+-circuit has a short circuit to ground or an open/high resistance.
10. Ignition switch ON, radio ON, check that a test lamp lights between the entertainment system's remote control activation circuit 6 and ground.
11. If the test lamp does not light, check if the entertainment system remote control activation circuit has a short circuit to ground or an open/high resistance. If the circuit tests OK, replace the A11 radio.
12. Check for 2-3V between the data circuit pin 4 and ground.
13. If the value is lower, check whether the data circuit is shorted to ground or is open/has high resistance. If the circuit tests OK, replace the A11 radio.
14. If higher value, check if the data circuit is short circuited to voltage. If the circuit tests OK, replace the A11 radio.
15. Check for 2-3V between the data circuit pin 8 and ground.
16. If the value is lower, check whether the data circuit is shorted to ground or is open/has high resistance. If the circuit tests OK, replace the A11 radio.
17. If higher value, check if the data circuit is short circuited to voltage. If the circuit tests OK, replace the A11 radio.
18. Ignition switch OFF, disconnect wiring harness connector from K31 navigation module.
19. Disconnect X3 connector from A11 radio.
20. Ignition switch ON, check for 3-5 V between display resetting circuit pin 10 and ground.
21. If the value is lower, check whether the signal circuit is shorted to ground or is open/has high resistance. If the circuit tests OK, replace K31 navigation module.
22. If higher value, check if the signal circuit is short circuited to voltage. If the circuit tests OK, replace K31 navigation module.
23. If all circuits are normal, replace the video interface cable. Reconnect all connectors.
24. Ignition switch ON, radio ON, check that the information display starts and that information is displayed on screen.
25. If the information display still does not function, replace K31 navigation module. Ignition switch ON, radio ON, check that the information display starts and that information is displayed on screen. If the information display still does not function, replace A11 radio.

1. Carry out «DIAGNOSTIC SYSTEM CHECK - VEHICLE»(ref-652232-S33658475782014082300000) before carrying out this diagnostic procedure.
2. See «STRATEGY BASED DIAGNOSTICS»(ref-652232-S31928919322014082300000) For an overview of the diagnostic procedure.
3. Instructions for diagnosis procedure gives an overview of each diagnostic category.

Control Module References ** for information about diagnostic tools.

1. Ignition switch OFF, disconnect wiring harness connector P17 on information display module.
2. Check so that there are fewer than 10 ohms between the ground circuit pin 2 and ground.
3. If higher value, check if ground has open/has high resistance.
4. Check so that there are fewer than 20 ohms between the data circuit pin 6 and ground.
5. If higher value, check if ground has open/has high resistance. If the circuit tests OK, replace the A11 radio.
6. Check with a test lamp between B+ pin 1 and ground.
7. If the test lamp does not light, check if the B+-circuit has a short circuit to ground or an open/high resistance.
8. Ignition switch in DRIVE, check for 2-3 V between data circuit pin 7 and ground.
9. If the value is lower, check whether the data circuit is shorted to ground or is open/has high resistance. If the circuit tests OK, replace the A11 radio.
10. If higher value, check if the data circuit is short circuited to voltage. If the circuit tests OK, replace the A11 radio.
11. Ignition switch in DRIVE, check for 2-3 V between data circuit pin 8 and ground.
12. If the value is lower, check whether the data circuit is shorted to ground or is open/has high resistance. If the circuit tests OK, replace the A11 radio.
13. If higher value, check if the data circuit is short circuited to voltage. If the circuit tests OK, replace the A11 radio.
14. Check that there is less than 1 V between wake-up signal pin 4 and ground.
15. If higher value, check if the signal circuit is short circuited to voltage. If the circuit tests OK, replace the A11 radio.
16. Check that there is less than 1 V between reset pin 5 and ground.
17. If higher value, check if the signal circuit is short circuited to voltage. If the circuit tests OK, replace the A11 radio.
18. Ignition switch OFF, reconnect wiring harness connector P17 on information display module.
19. Disconnect wiring harness X1 connector from A11 radio.
20. Check that there is 4.5-5.5 V between signal circuit pin 27 and ground.
21. If the value is lower, check whether the signal circuit is shorted to ground or is open/has high resistance. If the circuit is OK, replace the P17 information display module.
22. If higher value, check if the signal circuit is short circuited to voltage. If the circuit is OK, replace the P17 information display module.
23. Check that there is 4.5-5.5 V between signal circuit pin 13 and ground.
24. If the value is lower, check whether the signal circuit is shorted to ground or is open/has high resistance. If the circuit is OK, replace the P17 information display module.
25. If higher value, check if the signal circuit is short circuited to voltage. If the circuit is OK, replace the P17 information display module.
26. If all circuits are normal, replace P17 information display module. Reconnect all wiring harness connectors.
27. Ignition switch DRIVE, radio ON, check that the information display module starts and that information is displayed on screen.
28. If the information display module still does not function, replace A11 radio.