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Tahoe / Yukon Service Manual

Hill Descent Control Indicator Malfunction

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 Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Signal 1 1 1 —
Ground — 1 — —
1. Hill Descent Control Switch = Inoperative

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

Circuit Description
Signal The control module input circuit has an internal resistance connected to 12 V.
Ground Chassis Ground
Component Description
K9 Body Control Module The control module contains a microprocessor used to process input data to control outputs.
S86 Vehicle Stability Control System Switch The switch has a normally open contact.

Reference Information Schematic Reference Antilock Brake System 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 Verify the Hill Descent indicator turns ON and OFF during Instrument Panel Cluster initialization bulb check. ⇒ If the Hill Descent indicator does not turn ON and OFF Replace the component: P16 Instrument Panel Cluster Control Module ⇓ If the Hill Descent indicator turns ON and OFF
  2. Operate the component: S86 Vehicle Stability Control System Switch Verify the scan tool parameter: Hill Descent Control Switch @ K9 Body Control Module = Enabled ⇒ If not the specified state Refer to: Circuit/System Testing ⇓ If the specified state
  3. All OK. Circuit/System Testing
  1. Ignition/Vehicle = OFF
  2. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch
  3. Test for less than 10 Ω between the test points: Ground circuit terminal 10 & Ground ⇒ If 10 Ω or greater 3.1. Disconnect the ground connection: G200 3.2. Test for less than 2 Ω between the test points: Ground circuit terminal 10 @ Instrument Panel Multifunction Switch & Terminal G200 ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Repair the open/high resistance in the ground connection. ⇓ If less than 10 Ω
  4. Ignition » On / Vehicle » In Service Mode
  5. Verify the scan tool parameter: Hill Descent Control Switch @ K9 Body Control Module = Disabled ⇒ If not the specified state 5.1. Ignition/Vehicle » Off 5.2. Disconnect the electrical connector: X3 Harness Connector @ K9 Body Control Module 5.3. Test for infinite resistance between the test points: Signal circuit terminal 30 @ X3 Harness Connector & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇒ If infinite resistance » Replace the component: K9 Body Control Module ⇓ If the specified state
  6. Connect a 3 A fused jumper wire between the test points: S86 Vehicle Stability Control System SwitchSignal circuit terminal 9 & Ground circuit terminal  10
  7. Verify the scan tool parameter: Traction Control Switch @ K9 Body Control Module = Active ⇒ If not the specified state 7.1. Ignition/Vehicle » Off & Remove » Jumper wire(s) 7.2. Disconnect the electrical connector: X3 Harness Connector @ K9 Body Control Module 7.3. Ignition » On / Vehicle » In Service Mode 7.4. Test for less than 1 V between the test points: S86 Vehicle Stability Control System SwitchSignal circuit terminal 9 & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇓ If less than 1 V 7.5. Ignition/Vehicle » Off 7.6. Test for less than 2 Ω between the test points: S86 Vehicle Stability Control System SwitchSignal circuit terminal 9 & Terminal 30 @ X3 Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇒ If less than 2 Ω » Replace the component: K9 Body Control Module ⇓ If the specified state
  8. Test or replace the component: S86 Vehicle Stability Control System Switch Component Testing
  9. Ignition/Vehicle » Off
  10. Disconnect the electrical connector: S86 Vehicle Stability Control System Switch
  11. Test for infinite resistance between the test points: S86 Vehicle Stability Control System SwitchSignal circuit terminal 9 & Ground circuit terminal  10 ⇒ If less than infinite resistance Replace the component: S86 Vehicle Stability Control System Switch ⇓ If infinite resistance
  12. Press and hold the switch: » Hill Descent Control Switch
  13. Test for less than 2 Ω between the test points: S86 Vehicle Stability Control System Switch Signal circuit terminal 9 & Ground circuit terminal  9 ⇒ If 2 Ω or greater Replace the component: S86 Vehicle Stability Control System Switch ⇓ If less than 2 Ω
  14. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification For control module replacement, programming, and setup refer to: Control Module References