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Home >> Buick >> 2012 >> Regal Base >> Repair and Diagnosis >> Engine Performance >> System >> Data Communications System >> Diagnostic Information and Procedures >> DTC U18B9-U18BF >> Circuit/System Description
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Circuit/System Description

Control modules on the high speed GMLAN serial data bus and the chassis high speed GMLAN serial data bus must be programmed with software that specifically identifies the correct type and quantity of modules on the bus based on RPO configuration. If a control module was not properly configured after installation, the appropriate U Code may be set for that module. No external circuit diagnosis is involved.