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Tahoe / Yukon Service Manual

DTC B1023

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 B1023 Windshield Washer Switch Signal Diagnostic Fault Information

Circuit Number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
94 Signal B1023 9E — — B1023 9E
6009 Low Reference — — — B1023 9E

Circuit/System Description The K9 Body Control Module provides the S78 Turn Signal Switch with ground through a single low reference circuit and monitors the switch position through a single signal circuit. Voltage is applied by the K9 Body Control Module to this signal circuit and voltage drop is monitored to determine switch selection. The S78 Turn Signal Switch contains an internal switch dedicated to windshield washer operation. When the switch is closed, the signal circuit is pulled to ground, indicating washer operation is requested. Conditions for Running the DTC Ignition ON System voltage is between 9–16V. Conditions for Setting the DTC The K9 Body Control Module detects low signal voltage or an active switch press for greater than 10 seconds. Actions Taken When the DTC Sets The windshield washer function is disabled. Conditions for Clearing the DTC The conditions for setting the DTC no longer exist. A history DTC will clear after 40 consecutive malfunction-free ignition cycles. Reference Information Schematic Reference Wiper/Washer Schematics Connector End View Reference Master Electrical Component List Description and Operation Wiper/Washer System 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. Verify the Windshield Washer Switch scan tool parameter changes between OFF and ON when operating the washer switch on the S78 Turn Signal Switch. ⇒ If the parameter does not change Refer to Circuit/System Testing ⇓ If the parameter changes
  2. A fault is not currently present and may be an intermittent condition. Circuit/System Testing
  3. Ignition OFF, disconnect the X2 connector at the K9 Body Control Module.
  4. Verify the scan tool parameter Windshield Washer Switch is OFF. ⇒ If the parameter is not OFF Replace the K9 Body Control Module ⇓ If the parameter is OFF
  5. Test for infinite resistance between signal circuit terminal 26 and ground. ⇒ If less than infinite resistance 3.1. Test circuit 94 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 S82 Windshield Wiper/Washer Switch. ⇓ If infinite resistance
  6. Press and hold the washer switch on the S78 Turn Signal Switch.
  7. Test for less than infinite resistance between signal circuit terminal 26 and ground. ⇒ If less than infinite resistance 5.1. Test circuit 6009 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. 5.2. Test circuit 94 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. 5.3. Replace the S78 Turn Signal Switch. ⇓ If infinite resistance
  8. Replace the K9 Body Control Module. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Turn Signal Switch Replacement Control Module References for BCM replacement, programming, and setup