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Home >> Cadillac >> 2017 >> CT6 Plug-In >> Repair and Diagnosis (Single Page) >> Body & Frame >> Seats >> Power Seat System >> Diagnostic Information and Procedures >> DTC B1850: Driver Seat Lumbar Support Horizontal Position Sensor Circuit >> Circuit/System Testing

Circuit/System Testing

  1. Ignition/Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the M52D Seat Lumbar Support Horizontal Motor - Driver. 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 
    1. Ignition/Vehicle OFF, disconnect the X5 harness connector at the K40D Seat Memory Control Module - Driver.
    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 K40D Seat Memory Control Module - Driver.
    • If less than 10 Ω 
  3. Ignition ON/Vehicle in Service Mode.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.
    • If less than 4.8 V 
    1. Ignition/Vehicle OFF, disconnect the X5 harness connector at the K40D Seat Memory Control Module - Driver.
    2. Test for infinite resistance between the 5 V reference circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the 5 V 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 K40D Seat Memory Control Module - Driver.
    • If greater than 5.2 V 
    1. Ignition/Vehicle OFF, disconnect the X5 harness connector at the K40D Seat Memory Control Module - Driver, Ignition ON/Vehicle in Service Mode.
    2. Test for less than 1 V between the 5 V reference circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K40D Seat Memory Control Module - Driver.
    • If between 4.8-5.2 V 
  5. Verify the scan tool Driver Seat Lumbar Support Horizontal Position parameter is less than 0.22 V.
    • If 0.22 V or greater 
    1. Ignition/Vehicle OFF, disconnect the X5 harness connector at the K40D Seat Memory Control Module - Driver, Ignition ON/Vehicle in Service Mode.
    2. Test for less than 1 V between the signal circuit terminal 2 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K40D Seat Memory Control Module - Driver.
    • If less than 0.22 V 
  6. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the 5 V reference circuit terminal 1.
  7. Verify the scan tool Driver Seat Lumbar Support Horizontal Position parameter is greater than 4.75 V.
    • If 4.75 V or less 
    1. Ignition/Vehicle OFF, remove the 3 A fused jumper wire, disconnect the X5 harness connector at the K40D Seat Memory Control Module - Driver.
    2. Test for infinite resistance between the signal circuit terminal 2 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    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 K40D Seat Memory Control Module - Driver.
    • If greater than 4.75 V 
  8. Test or replace the M52D Seat Lumbar Support Horizontal Motor - Driver.
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