Skip to content
Tahoe / Yukon Service Manual

DTC B13A9

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 Roof Rail Air Bag Disable Switch Signal Symptom Byte Information: Symptom Byte List Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Roof Rail Air Bag Disable Switch Signal B13A9 11 B13A9 13 B13A9 12 —

Circuit/System Description For an overview of the component/system, refer to: Supplemental Inflatable Restraint System Description and Operation

Circuit Description
Signal The control module input circuit has an internal resistance connected to 12V
Low Reference Grounded through the control module.
Component Description
K36 Restraints Control Module The control module monitors several sensors that can detect a collision. When a collision is detected, the control module will trigger certain air bags and seat belt pretensioners, depending on the angle and severity of the impact.
S86 Vehicle Stability Control System Switch The switch has a normally open contact.

Conditions for Running the DTC Ignition = On Ignition Voltage = 9 to 16 V Conditions for Setting the DTC B13A9 11 Signal = Short to Ground — For greater than 2 s B13A9 12 Signal = Short to Voltage — For greater than 2 s B13A9 13 Signal = Open/High Resistance — For greater than 2 s Actions Taken When the DTC Sets Air Bag Malfunction Indicator = On Conditions for Clearing the DTC A current DTC will clear when the diagnostic runs and passes. A history DTC will clear after 50 consecutive malfunction-free ignition cycles. Reference Information Schematic Reference SIR 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 Verification

  1. Ignition » On / Vehicle » In Service Mode
  2. Press and release the switch: S86 Vehicle Stability Control System Switch Verify the component works as specified: Rollover Sensor — Indicators = On and Off ⇒ If the component does not turn On and Off Refer to: Circuit/System Testing
  3. All OK. Circuit/System Testing
  1. Ignition/Vehicle & All vehicle systems » Off
  2. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch
  3. Test for less than 10 Ω between the test points: Low Reference circuit terminal 14 & Ground ⇒ If 10 Ω or greater 3.1. Disconnect the electrical connector: K36 Restraints Control Module 3.2. Test for less than 2 Ω between the test points: Low Reference circuit terminal 14 @ Component harness & Terminal 50 @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K36 Restraints Control Module ⇓ If less than 10 Ω
  4. Connect the electrical connector: S86 Vehicle Stability Control System Switch
  5. Disconnect the electrical connector: K36 Restraints Control Module
  6. Ignition » On / Vehicle » In Service Mode
  7. Test for less than 1 V between the test points: Signal circuit terminal 51 & Ground ⇒ If 1 V or greater 7.1. Ignition/Vehicle & All vehicle systems » Off 7.2. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch 7.3. Ignition » On / Vehicle » In Service Mode 7.4. Test for less than 1 V between the test points: Signal circuit terminal 51 @ Control module harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇒ If less than 1 V » Test or replace the component: S86 Vehicle Stability Control System Switch ⇓ If less than 1 V
  8. Ignition/Vehicle & All vehicle systems » Off
  9. Test for infinite resistance between the test points: Signal circuit terminal 51 & Ground ⇒ If less than infinite resistance 9.1. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch 9.2. Test for infinite resistance between the test points: Signal circuit terminal 51 @ Control module harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Replace the component: S86 Vehicle Stability Control System Switch ⇓ If infinite resistance
  10. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch
  11. Test for less than 2 Ω between the test points: Signal circuit terminal 8 & The other end of the circuit @ Control module harness ⇒ If 2 Ω or greater Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
  12. Connect the electrical connector @ S86 Vehicle Stability Control System Switch
  13. Test for 360 to 440 Ω between the test points: Signal circuit terminal 51 & Low Reference circuit terminal 50 ⇒ If not between 360 and 440 Ω 13.1. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch 13.2. Test for less than 2 Ω between the test points: Signal circuit terminal 51 @ Control module harness & Terminal 8 @ Component harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: S86 Vehicle Stability Control System Switch ⇓ If between 360 and 440 Ω
  14. Press and hold the switch: S86 Vehicle Stability Control System Switch Test for 90 to 110 Ω between the test points: Signal circuit terminal 51 & Low Reference circuit terminal 50 ⇒ If not between 90 and 110 Ω Replace the component: S86 Vehicle Stability Control System Switch ⇓ If between 90 and 110 Ω
  15. Replace the component: K36 Restraints Control Module Component Testing
  16. Ignition/Vehicle » Off
  17. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch
  18. Test for 360 to 440 Ω between the test points: Signal terminal 8 & Low Reference terminal 14 at the switch in the open position. ⇒ If not between 360 and 440 Ω Replace the component: S86 Vehicle Stability Control System Switch ⇓ If between 360 and 440 Ω
  19. Test for 90 to 110 Ω between the test points: Signal terminal 8 & Low Reference terminal 14 at the switch in the closed position. ⇒ If not between 90 and 110 Ω Replace the component: S86 Vehicle Stability Control System Switch ⇓ If between 90 and 110 Ω
  20. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Vehicle Stability Control System Switch Replacement For control module replacement, programming, and setup refer to: Control Module References