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Tahoe / Yukon Service Manual

DTC B1B09

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 B1B09 Left Front Door Ajar Switch Signal 2 Symptom Byte Information: Symptom Byte List Diagnostic Fault Information

Circuit number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
8917 Signal B1B09 11 1 2 —
1. Upfitter provision circuit = Always Off 2. Upfitter provision circuit = Always On

Circuit/System Description The K9 Body Control Module supplies the A23D Front Side Door Latch-Driver a 5V Reference through the open switch signal circuit 126. The A23D Front Side Door Latch-Driver contains a multiplexed resistor. When the driver door is closed the open switch contacts will be open, when the door is open the contacts in the switch will close which will decrease the resistance between signal circuit 126 and ground. The body control module will then determine from the change in the voltage level that the door is open. When the K9 Body Control Module sees that the driver door is open, the K9 Body Control Module will apply battery voltage to the Upfitter Left Front Door Ajar Switch Signal 2 Circuit 8917. Conditions for Running the DTC Battery voltage is between 9–16 V. Conditions for Setting the DTC B1B09 11 Circuit 8917 = Short to Ground— For greater than 60 s . Action Taken When the DTC Sets Circuit 8917 Output = Disabled Conditions for Clearing the DTC The DTC will be current for as long as the fault is present. When the BCM receives a serial data message from the driver window motor that the door is ajar before the body control module detects the door open switch is active, then the DTC will be a history DTC. A history DTC will clear after 40 ignition cycles. Reference Information Schematic Reference Upfitter Provision Schematics Connector End View Reference Master Electrical Component List Description and Operation Door Ajar Indicator 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.
  2. Verify the scan tool Left Front Door Ajar Switch parameter changes between Ajar and Closed when opening and closing the driver door. ⇒ If the parameter does not change Refer to Door Ajar Indicator Malfunction ⇓ If the parameter changes
  3. Verify DTC B1038 is not set ⇒ If DTC B1038 is set Refer to DTC B1038 ⇓ If DTC B1038 is not set
  4. Verify DTC B1B09 is not set ⇒ If DTC B1B09 is set Refer to Circuit/System Testing ⇓ If DTC B1B09 is not set
  5. A fault is not currently present and may be an intermittent condition Circuit/System Testing
  6. Ignition » Off
  7. Disconnect any electrical components/modules connected to signal circuit 8917 after the W12RCL Blunt Cut - Left Rear Cargo Trim or W12FC Blunt Cut - Front Seat/Center Console.
  8. Ignition» On
  9. Driver door » Open
  10. Test for greater than 11.6V between the test points: Circuit 8917 & Ground. ⇒ If less than 11.6V 5.1. Ignition » Off 5.2. Disconnect the electrical connector: X6 at the K9 Body Control Module. 5.3. Test circuit 8917 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 5.4. Test circuit 8917 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. 5.5. Replace the K9 Body Control Module. ⇓ If greater than 11.6V
  11. Driver door » Closed
  12. Test for less than 1V between the test points: Circuit 8917 & Ground. ⇒ If greater than 1V 7.1. Disconnect the electrical connector: X6 at the K9 Body Control Module. 7.2. Test the circuit 8917 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. 7.3. Replace the K9 Body Control Module. ⇓ If less than 1V
  13. Repair the fault on the Upfitter circuit or components. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Control Module References for body control module replacement, setup, and programming