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Tahoe / Yukon Service Manual

DTC B1105

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 B1105 Seat Memory Switch Signal 1 For symptom byte information refer to Symptom Byte List. Diagnostic Fault Information

Circuit Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
615 Signal B1105 11 1 B1105 1C B1105 1C B19B6 9E
1551 Ground — 1 — —
1. Memory recall is inoperative

Scan Tool Data K40D Driver Seat Adjuster Memory Module

Data List Parameter Values Normal Operation
Seat Position Data Memory Recall Switches Inactive / Memory 1 / Memory 2 / Exit This parameter indicates the state of the memory recall switch.
Seat Memory Set Switch Inactive / Active This parameter indicates the state of the memory set switch.

Circuit/System Description Ground is supplied to the seat memory switch. When a memory switch is pressed, the 5 V signal circuit from the seat memory control module is pulled low through the switch contacts and series of resistors indicating the memory recall request. In response to this signal, the seat memory control module commands the appropriate seat motors to move to the pre-recorded seat positions stored in memory. Additionally, the seat memory control module sends serial data messages indicating the request to recall or store a memory position. Modules that locally recall and store positions are the mirror, column, MBM, and HUD modules (When equipped). Conditions for Running the DTC Battery voltage must be between 9–16 V. Conditions for Setting the DTC B1105 1C If the seat memory control module detects a voltage out of range on the memory seat switch signal circuit 615 this DTC will set. B1105 11 If the seat memory control module detects a short to ground on the memory seat switch signal circuit 615 this DTC will set. Actions Taken When the DTC Sets All Driver memory recall requests are ignored. Conditions for Clearing the DTCs The current DTC clears when the fault is no longer present. The history DTC will clear once 40 consecutive fault-free Ignition/Vehicle ON/OFF switch cycles have occurred. Diagnostic Aids After servicing the memory seat system it is recommended to move the seat to a central, middle range position, then perform the memory store operation for memory “1”, “2”, and “Exit” or “3” if equipped. Refer to the Owner Manual for storing memory seat positions. Additionally, It is recommended to inform the vehicle owner that the stored memory positions may differ due to the servicing of the seat system. The K40D Driver Seat Adjuster Memory Module must be awake when measuring voltage from either one of the memory seat switch signal circuits. If the module is not fully awake incorrect voltage readings are possible and may result in misdiagnosing the circuit. The K40D Driver Seat Adjuster Memory Module must have seat positions stored to each position “1”, “2”, and “Exit” or “3” prior to that position recall functioning. Reference Information Schematic Reference Driver Seat Schematics Connector End View Reference Master Electrical Component List Description and Operation Memory Seats 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/Vehicle in Service Mode.
  2. Verify the scan tool Memory Recall Switches parameter reads Inactive. ⇒ If the parameter does not read Inactive Refer to Circuit/System Testing. ⇓ If the parameter reads Inactive
  3. Verify the scan tool Memory Recall Switches parameter changes between Inactive and Memory 1 when pressing the Memory 1 switch. ⇒ If the parameter does not change Refer to Circuit/System Testing. ⇓ If the parameter changes
  4. Verify the scan tool Memory Recall Switches parameter changes between Inactive and Memory 2 when pressing the Memory 2 switch. ⇒ If the parameter does not change Refer to Circuit/System Testing. ⇓ If the parameter changes
  5. Verify the scan tool Memory Recall Switches parameter changes between Inactive and Exit when pressing the EXIT switch. ⇒ If the parameter does not change Refer to Circuit/System Testing. ⇓ If the parameter changes
  6. A fault is currently not present and may be an intermittent condition. Circuit/System Testing
  7. Ignition/Vehicle OFF, disconnect the connector at the S47D Front Seat Adjuster Memory Switch
  • Driver.
  1. Test for less than 10 Ω between the ground circuit terminal 2 and ground. ⇒ If 10 Ω or greater 2.1. Test circuit 1551 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 2.2. Repair the open/high resistance in the ground connection. ⇓ If less than 10 Ω
  2. Ignition/Vehicle in Service Mode.
  3. Press a power seat switch in order to wake up the K40D Driver Seat Adjuster Memory Module.
  4. Test for 4.8–5.2 Volts between the signal circuit terminal 3 and ground. ⇒ If less than 4.8 V 5.1. Test circuit 615 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 5.2. Test circuit 615 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 K40D Driver Seat Adjuster Memory Module. ⇒ If greater than 5.2 V 5.1. Test circuit 615 for a short to voltage: ⇒ If a short to voltage is found, repair the fault on the circuit. ⇓ If a short to voltage is not found 5.2. Replace the K40D Driver Seat Adjuster Memory Module. ⇓ If between 4.8–5.2 V
  5. Test or replace the S47D Front Seat Adjuster Memory Switch - Driver. Component Testing Front Seat Adjuster Memory Switch
  6. Ignition/Vehicle OFF, disconnect the connector at the S47D Front Seat Adjuster Memory Switch
  • Driver.
  1. Test for infinite resistance between each signal terminal listed below and the ground terminal 2 with the switch in the open position. Terminal 3 Terminal 4 ⇒ If less than infinite resistance Replace the S47D Front Seat Adjuster Memory Switch - Driver. ⇓ If infinite resistance
  2. Test for less than 4 Ω between the signal terminal 4 and the ground terminal 2 while pressing the memory SET button. ⇒ If 4 Ω or greater Replace the S47D Front Seat Adjuster Memory Switch - Driver. ⇓ If less than 4 Ω
  3. Test for 1140–1400 Ω between the signal terminal 3 and the ground terminal 2 while pressing the memory 1 button. ⇒ If not between 1140–1400 Ω Replace the S47D Front Seat Adjuster Memory Switch - Driver. ⇓ If between 1140–1400 Ω
  4. Test for 3790–4630 Ω between the signal terminal 3 and the ground terminal 2 while pressing the memory 2 button. ⇒ If not between 3790–4630 Ω Replace the S47D Front Seat Adjuster Memory Switch - Driver. ⇓ If between 3790–4630 Ω
  5. Test for 11.4–13.9 kΩ between the signal terminal 3 and the ground terminal 2 while pressing the Exit button. ⇒ If not between 11.4–13.9 kΩ Replace the S47D Front Seat Adjuster Memory Switch - Driver. ⇓ If between 11.4–13.9 kΩ
  6. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Control Module References for K40D Driver Seat Adjuster Memory Module replacement, programming, and setup