Cellular Telephone Microphone Malfunction (without UE1_ UDA)
Cellular, Entertainment, and Navigation | Diagnostic Information and Procedures | Document ID: 5521978 Cellular Telephone Microphone Malfunction (without UE1/ UDA) Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions Diagnostic Fault Information
| Circuit | Circuit Function | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performan |
|---|---|---|---|---|---|
| 655 | Signal | B1114 11 | B1114 13 | — | — |
| 654 | Low Reference | — | B1114 13 | — | — |
| 7043 | Signal | B1A36 11 | B1A36 13 | — | — |
| 7044 | Low Reference | — | B1A36 13 | — | — |
Circuit/System Description When the vehicle is not equipped with OnStar the A11 Radio provides the B24LF Mobile Telephone Microphone — Left Front with a supplied voltage on the cellular phone microphone high signal circuit 655. When the microphone is in use, voice data from the user is sent back to the radio on the cellular microphone low reference circuit 654. Some infotainment systems will use a secondary cellular microphone. When equipped the A11 Radio provides the B24RF Mobile Telephone Microphone — Right Front with a supplied voltage on the microphone high signal circuit 7043. When the microphone is in use, voice data from the user is sent back to the A11 Radio on the microphone low reference circuit 7044. This microphone is used for driver side hands free calling enhancement, as well as a reference microphone for the primary microphone. Reference Information Schematic Reference OnStar/Telematics Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References Circuit/System Verification
- Place a hands free cellular test call.
- Clearly speak into the left front and (if equipped) right front mobile telephone microphone. ⇒ If there is trouble being heard from the left front microphone Refer to Circuit/System Testing – B24LF Mobile Telephone Microphone – Left Front ⇒ If there is trouble being heard from the right front microphone Refer to Circuit/System Testing – B24RF Mobile Telephone Microphone – Right Front ⇓ If no trouble being heard from either microphone All OK. Circuit/System Testing B24LF Mobile Telephone Microphone – Left Front
- Ignition/vehicle OFF, disconnect the harness connector at the B24LF Mobile Telephone Microphone – Left Front, ignition ON/vehicle in service mode.
- Test for 8-11 V between the signal circuit terminal 2 and ground. ⇒ If less than 8 V 2.1. Test circuit 655 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 2.2. Test circuit 655 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 2.3. Replace the A11 Radio. ⇒ If greater than 11 V 2.1. Test circuit 655 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 2.2. Replace the A11 Radio. ⇓ If between 8-11 V
- Test for less than 1 V between the low reference circuit terminal 1 and ground. ⇒ If greater than 1 V 3.1. Test circuit 654 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 3.2. Replace the A11 Radio. ⇓ If less than 1 V
- Test for greater than 8 V between the signal circuit terminal 2 and the low reference circuit terminal 1. ⇒ If less than 8 V 4.1. Test circuit 654 for an open/high resistance in the circuit. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 4.2. Replace the A11 Radio. ⇓ If greater than 8 V
- Replace the B24LF Mobile Telephone Microphone – Left Front. B24RF Mobile Telephone Microphone – Right Front
- Ignition/vehicle OFF, disconnect the harness connector at the B24RF Mobile Telephone Microphone – Right Front, ignition ON/vehicle in service mode.
- Test for 8-11 V between the signal circuit terminal 1 and ground. ⇒ If less than 8 V 2.1. Test circuit 7043 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 2.2. Test circuit 7043 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 2.3. Replace the A11 Radio. ⇒ If greater than 11 V 2.1. Test circuit 7043 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 2.2. Replace the A11 Radio. ⇓ If between 8-11 V
- Test for less than 1 V between the low reference circuit terminal 2 and ground. ⇒ If greater than 1 V 3.1. Test circuit 7044 for a short to voltage. ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 3.2. Replace the A11 Radio. ⇓ If less than 1 V
- Test for greater than 8 V between the signal circuit terminal 1 and the low reference circuit terminal 2. ⇒ If less than 8 V 4.1. Test circuit 7044 for an open/high resistance in the circuit. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 4.2. Replace the A11 Radio.
- Replace the B24RF Mobile Telephone Microphone – Right Front. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Roof Console Replacement For control module replacement, programming, and setup refer to: Control Module References