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Tahoe / Yukon Service Manual

DTC B1A36

Cellular, Entertainment, and Navigation | Diagnostic Information and Procedures | Document ID: 5159207 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 DTC Descriptor DTC B1A36 Microphone Signal Symptom Byte Information: Symptom Byte List Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Signal circuit B1A36 11 B1A36 13 — —
Low Reference circuit B1A36 11 B1A36 13 — —

Circuit/System Description The radio provides the right front microphone with a supplied voltage on the microphone high signal circuit. When the microphone is in use, voice data from the user is sent back to the radio on the microphone low signal circuit. This microphone is used for driver side hands free calling enhancement, as well as a reference microphone for the primary microphone. Conditions for Running the DTC Ignition On System Voltage = 9.5 to 15.5 V Conditions for Setting the DTC B1A36 11 The radio detects a short to ground in the microphone (+) signal circuit for 5 s or greater. B1A36 13 The radio detects an open/high resistance in the microphone (+) signal circuit for 10 s or greater. Actions Taken When the DTC Sets Microphone Signal = Inoperative Conditions for Clearing the DTC The conditions for setting the DTC no longer exist. A history DTC will clear after 100 consecutive malfunction-free ignition cycles. Reference Information Schematic Reference Radio/Navigation System 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 Testing

  1. Ignition/Vehicle & All vehicle systems » Off
  2. Disconnect the electrical connector: B24RF Mobile Telephone Microphone - Right Front
  3. Ignition » On / Vehicle » In Service Mode
  4. Test for 8.0 to 10.5 V between the test points: Signal circuit terminal 2 & Ground ⇒ If less than 8.0 V 4.1. Ignition/Vehicle & All vehicle systems » Off 4.2. Disconnect the electrical connector: X1 @ A11 Radio 4.3. Test for infinite resistance between the test points: Signal circuit terminal 2 & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 4.4. Test for less than 2 Ω between the test points: Signal circuit terminal 2 & The other end of the circuit ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: A11 Radio ⇒ If greater than 10.5 V 4.1. Ignition/Vehicle & All vehicle systems » Off 4.2. Disconnect the electrical connector: X1 @ A11 Radio 4.3. Ignition » On / Vehicle » In Service Mode 4.4. Test for less than 1 V between the test points: Signal circuit terminal 2 & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇒ If less than 1 V » Replace the component: A11 Radio ⇓ If between 8.0 and 10.5 V
  5. Test for less than 1 V between the test points: Low Reference circuit terminal 1 & Ground ⇒ If greater than 1 V 5.1. Ignition/Vehicle & All vehicle systems » Off 5.2. Disconnect the electrical connector: X1 @ A11 Radio 5.3. Ignition » On / Vehicle » In Service Mode 5.4. Test for less than 1 V between the test points: Low Reference circuit terminal 1 & Ground 5.5. If 1 V or greater » Repair the short to voltage on the circuit. 5.6. If less than 1 V » Replace the component: A11 Radio ⇓ If less than 1 V
  6. Test for greater than 8 V between the test points: Signal circuit terminal 2 & Low Reference circuit terminal 1 ⇒ If less than 8 V 6.1. Ignition/Vehicle & All vehicle systems » Off 6.2. Disconnect the electrical connector: X1 @ A11 Radio 6.3. Test for infinite resistance between the test points: Low Reference circuit terminal 1 & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance 6.4. Test for less than 2 Ω between the test points: Low Reference circuit terminal 1 & The other end of the circuit 6.5. If 2 Ω or greater » Repair the open/high resistance in the circuit. 6.6. If less than 2 Ω » Replace the component: A11 Radio ⇓ If greater than 8 V
  7. Test or replace the component: B24RF Mobile Telephone Microphone - Right Front Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification For control module replacement, programming, and setup refer to: Control Module References