DTC B2119: Lumbar Forward/Aft Position Sensor Failed: Testing

2000 Buick Park Avenue Base, 3.8 KSECTION Testing
  1. Perform POWER SEATS DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. Go to next step.
  2. Disconnect lumbar forward/aft position sensor (located in seat back). Measure voltage between lumbar forward/aft position sensor harness connector ground circuit terminal (Orange wire) and 5-volt supply circuit terminal (Light Blue wire). If 4.5-5.2 volts exists, go to next step. If 4.5-5.2 volts does not exist, go to step  4 .
  3. Check for short to ground, high resistance or open in lumbar forward/aft position sensor return circuit (Black wire) between lumbar forward/aft position sensor and MSM. Repair as necessary. See WIRING DIAGRAMS  . After repair, go to step  10 . If lumbar forward/aft position sensor return circuit is okay, go to next step.
  4. Check for high resistance or open in 5-volt reference circuit (Gray wire) between lumbar forward/aft position sensor and MSM. Repair as necessary. See WIRING DIAGRAMS  . After repair, go to step  10 . If 5-volt reference circuit is okay, go to next step.
  5. Check for high resistance or open in lumbar forward/aft position sensor return circuit (Black wire) between lumbar forward/aft position sensor and MSM. Repair as necessary. See WIRING DIAGRAMS  . After repair, go to step  10 . If lumbar forward/aft position sensor return circuit is okay, go to step  7 .
  6. Check for poor terminal contact at lumbar forward/aft position sensor harness connector. Repair as necessary. After repair, go to step  10 . If terminal contact is okay, go to step  8 .
  7. Check for poor terminal contact at MSM harness connector. Repair as necessary. After repair, go to step  10 . If terminal contact is okay, go to step  9 .
  8. Replace lumbar forward/aft position sensor. See POSITION SENSORS  under REMOVAL & INSTALLATION. After repair, go to step  10 .
  9. Replace MSM. See MEMORY SEAT MODULE  under REMOVAL & INSTALLATION. After repair, go to next step.
  10. Using scan tool, clear DTCs. Recheck system operation. If DTC resets, go to step  2 . If no DTCs exist, system is okay at this time.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.