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Tahoe / Yukon Service Manual

DTC B110A

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 Descriptor Head-Up Display Switch Signal Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Signal B110A 11 B110A 15 B110A 15 B110A 63
Low Reference — B110A 15 — —

Circuit/System Description The head-up display switch is a multiplexed switch that controls the head-up display based on driver inputs. The head-up display provides the switch with a low reference and monitors a signal circuit. The head-up display switch is made up of a resistor ladder and three switches: Dim +/-, Up/Down, and Page. When a switch is pressed, the signal voltage is pulled low through the resistor ladder. When pressed, each of the switches will result in a different signal voltage seen by the head-up display, depending on the switch’s location on the resistor ladder. Conditions for Running the DTC Ignition ON/Vehicle in Service Mode. Conditions for Setting the DTC B110A 11 The head-up display switch signal voltage is less than 1 V B110A 15 The head-up display switch signal voltage is greater than 11.5 V B110A 63 The head-up display switch is stuck Action Taken When the DTC Sets The head-up display ignores the head-up display switch inputs Conditions for Clearing the DTC The DTC will become history if the head-up display no longer detects a malfunction Reference Information Reference Information Schematic Reference Head-Up Display Schematics Connector End View Reference Master Electrical Component List Description and Operation Instrument Cluster 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/Vehicle in Service Mode.
  2. Verify the P29 Head-Up Display performs the following function with the switch in the appropriate state: DIM + Switch – Head-up display brightness increases DIM - Switch – Head-up display brightness decreases UP Switch – Head-up display image moves up DOWN Switch – Head-up display image moves down INFO Switch – Head-up display image changes pages POWER Switch – Head-up display image turns off ⇒ If the P29 Head-Up Display does not perform the expected function with the switch in the appropriate state Refer to Circuit/System Testing. ⇓ If the P29 Head-Up Display performs the expected function with the switch in the appropriate state
  3. All OK. Circuit/System Testing
  1. Ignition OFF/Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the S27 Head-Up Display Switch. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal 3 and ground. ⇒ If 10 Ω or greater 2.1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the P29 Head-Up Display. 2.2. Test for less than 2 Ω in the low reference circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the P29 Head-Up Display. ⇓ If less than 10 Ω
  3. Test for 4.8–5.2 V between the signal circuit terminal 4 and ground. ⇒ If less than 4.8 V 3.1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the P29 Head-Up Display. 3.2. Test for infinite resistance between the signal circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 3.3. Test for less than 2 Ω in the signal circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the P29 Head-Up Display. ⇒ If greater than 5.2 V 3.1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the P29 Head-Up Display, ignition ON. 3.2. Test for less than 1 V between the signal circuit and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the P29 Head-Up Display. ⇓ If between 4.8–5.2 V
  4. Test or replace the S27 Head-Up Display switch. Component Testing
  5. Ignition OFF/Vehicle OFF, disconnect the harness connector at the S27 Head-Up Display Switch.
  6. Test for 3.7K – 3.9K Ω between the signal terminal 4 and the low reference terminal 3. ⇒ If not between 3.7K – 3.9K Ω Replace the S27 Head-Up Display Switch. ⇓ If between 3.7K – 3.9K Ω
  7. Test for 1K – 1.2K Ω between the signal terminal 4 and the low reference terminal 3 with the HUD DOWN Switch pressed. ⇒ If not between 1K – 1.2K Ω Replace the S27 Head-Up Display switch. ⇓ If between 1K – 1.2K Ω
  8. Test for 0.55K – 0.75K Ω between the signal terminal 4 and the low reference terminal 3 with the HUD UP Switch pressed. ⇒ If not between 0.55K – 0.75K Ω Replace the S27 Head-Up Display switch. ⇓ If between 0.55K – 0.75K Ω
  9. Test for 1.8K – 2.0K Ω between the signal terminal 4 and the low reference terminal 3 with the INFO/PAGE Switch pressed. ⇒ If not between 1.8K – 2.0K Ω Replace the S27 Head-Up Display Switch. ⇓ If between 1.8K – 2.0K Ω
  10. Test for 95 – 115 Ω between the signal terminal 4 and the low reference terminal 3 with the Brightness + Switch pressed. ⇒ If not between 1.3K – 1.6K Ω Replace the S27 Head-Up Display Switch. ⇓ If between 1.3K – 1.6K Ω
  11. Test for 310–350 Ω between the signal terminal 4 and the low reference terminal 3 with the Brightness – Switch pressed. ⇒ If not between 310–350 Ω Replace the S27 Head-Up Display Switch. ⇓ If between 310–350 Ω
  12. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Displays and Gauges Component Replacement Reference Control Module References for control module replacement, programming and setup