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Home >> Buick >> 2017 >> LaCrosse Essence >> Repair and Diagnosis >> Engine Performance >> System >> Data Communication System - Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC U18AA: Transmission Range Control Module Lost Communication with Engine Control Module >> Diagnostic Fault Information
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Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
B+ U18AA U18AA - -
Ignition U18AA U18AA - -
Accessory Wakeup Serial Data U1814, U2099 U18AA - -
High Speed GMLAN Serial Data (+) U0073* U0073, U18AA* U0073* -
High Speed GMLAN Serial Data (-) U0073* U0073, U18AA* U0073* -
Ground - U18AA - -
* Other DTCs may set with this fault.
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