Skip to content
Tahoe / Yukon Service Manual

DTC B19EC or B19ED

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 B19EC 92 Front Sunroof Sunshade Motor Open Control — Performance DTC B19ED 92 Rear Sunshade Motor Open Control — Performance Circuit/System Description The sunshade is controlled by its own integrated motor/controller containing the necessary electronics, motor, hall effect position sensors, as well as the interface to the driver control switches. The motor/controller is capable of controlling motion based on control switch activation and serial data message commands from the body control module (BCM). Conditions for Running the DTC The ignition is ON/Vehicle in Service Mode. Conditions for Setting the DTC B19EC 92 The Sunroof module has detected and reported via serial data that the Sunroof actuator has a performance malfunction. Action Taken When the DTC Sets DTC B19EC or B19ED is stored in the BCM memory. Conditions for Clearing the DTC The BCM no longer detects a malfunction in the sunshade actuator 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 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 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
  4. 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 Circuit/System Testing. ⇓ If the sunshade opens and closes
  5. All OK. Circuit/System Testing
  6. Ignition/vehicle OFF, disconnect the harness connector at the M81 Sunroof Sunshade Motor.
  7. Verify a test lamp illuminates between low reference circuit terminal and B+. ⇒ If the test lamp does not illuminate 2.1. Test the low reference circuit 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. 2.2. Replace the K61 Sunroof Control Module. ⇓ If the test lamp illuminates
  8. Install a test lamp between control circuit 3781 and control circuit 3782 at the M81 Sunroof Sunshade harness connector.
  9. Verify the test lamp momentarily turns On and Off when pressing the sunshade switch Open and Closed. ⇒ If the test lamp is always Off 4.1. Disconnect harness connector at K61 Sunroof Control module. 4.2. Test circuits listed below for a short to ground. Circuit 3781 Circuit 3782 ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found. 4.3. Disconnect harness connector at K61 Sunroof Control module. 4.4. Test circuits listed below for an open/high resistance. Circuit 3781 Circuit 3782 ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found. 4.5. Replace the K61 Sunroof Control Module. ⇒ If the test lamp is always On 4.1. Ignition/vehicle OFF, disconnect the harness connector at the K61 Sunroof Control Module 4.2. Test for less than 1 V between control circuits listed below and ground. Circuit 3781 Circuit 3782 ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found. 4.3. Replace the K61 Sunroof Control Module. ⇓ If the test lamp turns On and Off
  10. Replace the M81 Sunroof Sunshade Motor Repair Instructions Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Control Module References for sunroof and sunshade motor/actuator replacement, setup and programming