DTC B2600: DRL Error: Testing

1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4SECTION Testing
WARNING: This page is about a different car, the 1998 Oldsmobile Cutlass and 1998 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
  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. If any other DRL DTCs exist, go to next step. If no other DRL DTCs exist, go to step 4).
  3. Repair all other DRL DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  . If system is operating properly, go to step 7). If system is not operating properly, go to next step.
  4. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If automatic lighting control operates properly, go to next step. If automatic lighting control does not operate properly, go to step 6).
  5. Clear DTCs. Check for DTCs. If DTC B2600 exists, go to next step. If DTC B2600 does not exist, go to step 7).
  6. Replace BFC. See REMOVAL & INSTALLATION  . Go to next step.
  7. Clear DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  .


  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. If any other DRL DTCs exist, go to next step. If no other DRL DTCs exist, go to step 4).
  3. Repair all other DRL DTCs. Perform BFC DIAGNOSTIC SYSTEM CHECK  . If system is operating properly, go to step 7). If system is not operating properly, go to next step.
  4. Remove DRL relay from underhood wiring harness junction block. Replace DRL relay with a known-good relay. Using scan tool, enable DRL relay. If automatic lighting control operates properly, go to next step. If automatic lighting control does not operate properly, go to step 6).
  5. Clear DTCs. Check for DTCs. If DTC B2600 exists, go to next step. If DTC B2600 does not exist, go to step 7).
  6. Replace BFC. See REMOVAL & INSTALLATION  . Go to next step.
  7. 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.