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Tahoe / Yukon Service Manual

Power Sunroof_Sunshade Malfunction

Power Sunroof/Sunshade Malfunction 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. Diagnostic Fault Information

Circuit Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
240 B+ U1121, 1, 2 U1121, 1, 2 U1121, 1, 2 —
4540 B+ 1,2 1,2 — —
5033 12 V Reference 2 2 2 —
2854 Serial Data U1121, U0169 U1121, U0169 U1121, U0169 —
3781 Control 2 2 2 —
3782 Control 2 2 2 —
5034 Signal 2 2 2 —
5124 Signal 2 2 2 —
128 Low Reference 2 2 2 —
1050 Ground — 1,2 1,2 —
1850 Ground U1121, 1, 2 U1121, 1, 2 U1121, 1, 2 —
1. Power Sunroof Malfunction 2. Power Sunshade Malfunction

Circuit/System Description The sunroof electrical system uses a master/slave configuration utilizing a LIN-Bus based system for communication. The body control module (BCM) is designated as the master, while the sunroof and overhead console are configured as the slaves. The BCM uses the LIN-Bus communication bus to enable or disable sunroof and sunshade operation, communicate vehicle information to the controller, and request sunroof or sunshade movement. 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 Circuit/System Testing – Power Sunroof Malfunction. ⇓ If the sunroof opens and closes to the vent position
  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 Circuit/System Testing – Power Sunshade Malfunction. ⇓ If the sunshade opens and closes
  7. All OK. Circuit/System Testing Power Sunroof Malfunction
  8. Ignition/vehicle OFF, disconnect the harness connector at the K61 Sunroof Control Module
  9. Verify a test lamp illuminates between ground circuit terminals listed below and B+. Ground circuit terminal 2 Ground circuit terminal 8 ⇒ If the test lamp does not illuminate 2.1. Repair the open/high resistance on circuit 1050 or ground connection. ⇓ If the test lamp illuminates
  10. Ignition ON/vehicle in service mode, verify a test lamp illuminates between B+ circuits listed below and ground. B+ circuit terminal 10 B+ circuit terminal 11 ⇒ If the test lamp does not illuminate and the circuit fuse is OK 3.1. Test circuit 4540 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, verify there is voltage at the fuse. ⇒ If the test lamp does not illuminate and the circuit fuse is open 3.1. Test circuit 4540 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. 3.2. Replace the K61 Sunroof Control Module ⇓ If the test lamp Illuminates
  11. Replace the K61 Sunroof Control Module Power Sunshade Malfunction
  12. Ignition/vehicle OFF, disconnect the harness connector at the M81 Sunroof Sunshade Motor.
  13. Verify a test lamp illuminates between low reference circuit terminal 7 and B+. ⇒ If the test lamp does not illuminate 2.1. Test circuit 128 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
  14. Ignition ON/vehicle in service mode, test for 11.8 V – 12.2 V between 12 V reference circuit terminal 3 and ground. ⇒ If less than 11.8 V 3.1. Test circuit 5033 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. 3.2. Test circuit 5033 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. 3.3. Replace the K61 Sunroof Control Module. ⇒ If greater than 12.2 V 3.1. Disconnect the harness connector at the K61 Sunroof Control Module. 3.2. Test circuit 5033 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. 3.3. Replace the K61 Sunroof Control Module. ⇓ If between 11.8 V – 12.2 V
  15. Install a test lamp between control circuit terminal 1 and control circuit terminal 5.
  16. Verify the test lamp momentarily turns On and Off when pressing the sunshade switch Open and Closed. ⇒ If the test lamp is always Off 5.1. 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. 5.2. 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. 5.3. Replace the K61 Sunroof Control Module. ⇒ If the test lamp is always On 5.1. Ignition/vehicle OFF, disconnect the harness connector at the K61 Sunroof Control Module 5.2. 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. 5.3. Replace the K61 Sunroof Control Module. ⇓ If the test lamp turns On and Off
  17. Ignition/vehicle OFF, disconnect the harness connector at the K61 Sunroof Control Module
  18. Test for less than 1 V between control circuits listed below and ground. Signal circuit terminal 17 Signal circuit terminal 18 ⇒ If 1 V or greater 7.1. Repair the short to voltage on appropriate circuits listed below. Circuit 3781 Circuit 3782 ⇓ If less than 1 V
  19. Test for less than 1 V between signal circuits listed below and ground. Signal circuit terminal 14 Signal circuit terminal 15 ⇒ If 1 V or greater 8.1. Repair the short to voltage on appropriate circuits listed below. Circuit 5124 Circuit 5034 ⇓ If less than 1 V
  20. Ignition/vehicle off, test for infinite resistance between signal circuits listed below and ground. Signal circuit terminal 14 Signal circuit terminal 15 ⇒ If less than infinite resistance 9.1. Repair the short to ground on the appropriate circuits listed below. Circuit 5124 Circuit 5034 ⇓ If infinite resistance
  21. Test for less than 10 Ω between signal circuit terminals listed below and the other end of the circuit. Signal circuit terminal 14 Signal circuit terminal 15 ⇒ If 10 Ω or greater 10.1. Repair the open/high resistance on the appropriate circuits listed below. Circuit 5124 Circuit 5034 ⇓ If less than 10 Ω
  22. Replace the M81 Sunroof Sunshade Motor. Repair Instructions Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Sunroof Control Module Replacement Sunroof Housing Replacement Sunroof Sunshade Motor Replacement Control Module References for Sunroof Sunshade Motor - Front motor/actuator replacement, setup, and programming