Skip to content
Tahoe / Yukon Service Manual

DTC B15FD

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. DTC Descriptors DTC B15FD Sunroof Switch Serial Data 1 Signal For symptom byte information refer to Symptom Byte List. Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Signal B15FD 11 B15FD 15 B15FD 15 B15FD 23
Low Reference B15FD 11 B15FD 15 B15FD 15 B15FD 23

Circuit/System Description The sunroof switch is connected directly to the sunroof motor and provides detent positions for open, express open, off, close, and express close. The sunroof switch completes the circuit between two signals proved by the sunroof motor, a reference ground input and a pull-up voltage provided by an analog to digital switch input. The sunroof switch places a different resistor ladder network in the circuit depending on the function selected. Conditions for Running the DTC The ignition is ON. Conditions for Setting the DTC B15FD 11 The sunroof motor has detected and reported via serial data that the sunroof switch signal is shorted to ground. B15FD 15 The sunroof motor has detected and reported via serial data that the sunroof switch signal is open or shorted to voltage. B15FD 23 The sunroof motor has detected and reported via serial data that the sunroof switch has been in the same active position for 20 s after the glass has stopped moving in the requested direction due to reaching the end of the allowable motion. Action Taken When the DTC Sets DTC is stored in the body control module (BCM) memory. Conditions for Clearing the DTC The BCM no longer detects a malfunction in the sunroof switch signal circuit. Reference Information Schematic Reference Sunroof Schematics Connector End View Reference Master Electrical Component List Description and Operation Sunroof Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Circuit/System Verification

  1. Ignition ON/Vehicle in Service Mode.
  2. Verify DTC U0169 or U1121 are not set. ⇒ If DTC U0169 or U1121 are set Refer to Diagnostic Trouble Code (DTC) List - Vehicle. ⇓ If DTC U0169 or U1121 are not set
  3. Verify the K9 Body Control Module scan tool Sunroof Switch parameter changes from Inactive to Close, Open, Stop, Vent when pressing the Sunroof Switch. ⇒ If the parameters do not change Replace the A103 Roof Console. ⇓ If the parameters change
  4. Command the sunroof to open and close by pressing the appropriate switch on the A103 Roof Console. ⇒ If the sunroof does not open or close Refer to Power Sunroof/Sunshade Malfunction ⇓ If the sunroof opens and closes
  5. Verify the K9 Body Control Module scan tool Sunshade Switch parameter changes from Inactive to Open, Express Open, Close and Express Close when pressing the Sunshade Switch. ⇒ If the parameters do not change Replace the A103 Roof Console. ⇓ If the sunshade opens and closes
  6. Command the sunshade to open and close by pressing the appropriate switch on the Sunshade Switch. ⇒ If the sunshade does not open or close Refer to Power Sunroof/Sunshade Malfunction ⇓ If the sunshade opens and closes
  7. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Control Module References for sunroof and sunshade motor/actuator replacement, setup and programming