1998 Oldsmobile Cutlass BaseFACTORY OEM SERVICE PROCEDURE

DTC U2004: Transmitted SPI Data Output Low: Testing

  1. If BFC diagnostic system check was performed, go to next step. If BFC diagnostic system check was not performed, see procedures in BFC DIAGNOSTIC SYSTEM CHECK  .
  2. Disconnect BFC Pink 24-pin connector C3. Turn ignition switch to RUN position. Using DVOM, check voltage at BFC harness connector C3, terminal A3 (Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  3. Check for a poor connection at BFC connector C3, terminal A3 (Yellow wire). If a poor connection exists, go to next step. If connection is okay, go to step 5).
  4. Repair poor connection at BFC connector C3, terminal A3 (Yellow wire). Go to step 13).
  5. Replace BFC. See REMOVAL & INSTALLATION  . Go to step 13).
  6. Disconnect instrument cluster Gray 24-pin connector. Using DVOM, check resistance between BFC harness connector C3, terminal A3 (Yellow wire) and instrument cluster harness connector terminal A9 (Yellow wire). If resistance is 0-2 ohms, go to next step. If resistance is not 0-2 ohms, go to step 8).
  7. Check resistance between BFC harness connector C3, terminal A3 (Yellow wire) and ground. If resistance is infinite, go to step 10). If resistance is not infinite, go to step 9).
  8. Repair open in Yellow wire between BFC connector C3 and instrument cluster. Go to step 13).
  9. Repair short to ground in Yellow wire between BFC connector C3 and instrument cluster. Go to step 13).
  10. Check for a poor connection at instrument cluster connector terminal A9 (Yellow wire). If a poor connection exists, go to next step. If connection is okay, go to step 12).
  11. Repair poor connection at instrument cluster connector terminal A9 (Yellow wire). Go to step 13).
  12. Replace instrument cluster. See INSTRUMENT PANEL article. Go to next step.
  13. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  .
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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.

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