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 Cadillac Eldorado BaseFACTORY OEM SERVICE PROCEDURE
DTC U1255: Class 2 Initialization Error: Testing
- Clear DTCs and cycle ignition. Check for DTCs. If DTC U1255 exists, use scan tool to establish communication with each module on class 2 data bus. If all modules are communicating properly, go to next step. If any module is not communicating properly, repair or replace as necessary.
- Check for intermittent open in Purple wire between individual control modules. See WIRING DIAGRAMS . If circuit is okay, replace PZM. See REMOVAL & INSTALLATION.
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.
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