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Tahoe / Yukon Service Manual

DTC B1A4C

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 B1A4C 92 Heated Steering Wheel - Performance Diagnostic Fault Information

Circuit Number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performance
5885 B+ B1A4C 92, 1 B1A4C 92, 1 — B1A4C 92, 1
5886 Signal — B1A4C 92, 1 B1A4C 92, 1 B1A4C 92, 1
5887 Control B1A4C 92, 1 B1A4C 92, 1 B1A4C 92, 1 B1A4C 92, 1
5888 Control — B1A4C 92, 1 B1A4C 92, 1 B1A4C 92, 1
1. Heated Steering Wheel Inoperative

Circuit/System Description The K32 Heated Steering Wheel Module controls the heated steering wheel and the heated steering wheel indicator based on an input from the heated steering wheel switch. When the heated steering wheel switch is pressed, the signal circuit 5883 is pulled to ground. This indicates to the K32 Heated Steering Wheel Module that steering wheel heat is requested. When the request is seen, the K32 Heated Steering Wheel Module supplies voltage to the indicator lamp and supplies voltage to the heating elements, which are internal to the steering wheel. Conditions for Running the DTC The system voltage is between 9–16 V. Vehicle power mode is RUN for 5 seconds. Conditions for Setting the DTC The K32 Heated Steering Wheel Module detects a malfunction or incorrect operation of the Steering Wheel Heater element. Action Taken When the DTC Sets The heated steering wheel is inoperable. Conditions for Clearing DTC The conditions for setting the DTC no longer exist. Reference Information Schematic Reference Steering Wheel Schematics Connector End View Reference Master Electrical Component List Description and Operation Steering Wheel and Column Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Circuit/System Verification

  1. Ignition ON.
  1. Verify the scan tool Heated Steering Wheel parameter changes between Active and Inactive when cycling the heater steering wheel switch. ⇒ If the parameter does not change Refer to Circuit/System Testing ⇓ If the parameter changes
  2. Verify the scan tool Heated Steering Wheel Internal Temperature parameter changes from Off to Low / Medium / High after a few minutes. ⇒ If the parameter does not change Refer to Circuit/System Testing ⇓ If the parameter changes
  3. A fault is currently not present and may be an intermittent condition. Circuit/System Testing
  4. Ignition OFF, disconnect the X2 connector at the K32 Heated Steering Wheel Module, ignition ON.
  1. Test for less than 1 V between control circuit terminal 1 and ground. ⇒ If 1 V or greater Replace the E15 Steering Wheel Heater. ⇓ If less than 1 V
  1. Test for less than 1 V between voltage reference circuit terminal 4 and ground. ⇒ If 1 V or greater Replace the E15 Steering Wheel Heater. ⇓ If less than 1 V
  2. Ignition OFF.
  1. Test for infinite resistance between control circuit terminal 1 and ground. ⇒ If less than infinite resistance Replace the E15 Steering Wheel Heater. ⇓ If infinite resistance
  1. Test for infinite resistance between voltage reference circuit terminal 4 and ground. ⇒ If less than infinite resistance Replace the E15 Steering Wheel Heater.
  1. Test for 1.5–3.0 Ω between control circuit terminal 1 and control circuit terminal 2. ⇒ If not within the specified range Replace the E15 Steering Wheel Heater. ⇓ If within the specified range
  1. Test for 9–11k Ω between 12 V reference terminal 4 and signal circuit terminal 3. ⇒ If not within the specified range Replace the E15 Steering Wheel Heater. ⇓ If within the specified range
  2. Replace the K32 Heated Steering Wheel Module. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Steering Wheel Replacement Control Module References for control module replacement, programming and setup.