Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1998 Buick Century CustomFACTORY OEM SERVICE PROCEDURE
DTC B0603: BCM Internal Memory Malfunction (Write Error): Testing
- If BCM diagnostic system check was performed, go to next step. If BCM diagnostic system check was not performed, see procedures in BCM DIAGNOSTIC SYSTEM CHECK .
- Using scan tool, clear BCM DTCs. See BCM DTC DEFINITIONS under SELF-DIAGNOSTIC SYSTEM. Turn ignition switch to LOCK position. Wait 10 seconds. Turn ignition switch to RUN position. Using scan tool, check for codes. If DTC B0603 is set, go to next step. If DTC B0603 is not set, go to step 4).
- Replace BCM. See REMOVAL & INSTALLATION . Reprogram BCM. See BCM PROGRAMMING . Go to step 5).
- System is operating properly at this time. See DIAGNOSTIC AIDS.
- Turn ignition switch to LOCK position. Reinstall all components and connectors. Turn ignition switch to RUN position. Using scan tool, clear DTCs. Check for DTCs. If any DTCs are current, perform BCM DIAGNOSTIC SYSTEM CHECK . If no DTCs are current, system is operating properly.
Factory Service Tools
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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.