Fault Family System: Network (U-Codes) 10 SAE Codes

Control Module Network Wakeup Fault

Diagnostic & Technical Explanation

U3012 relates to the dedicated wake-up line or internal real-time clock that brings a control module out of sleep mode when the network needs it -- distinct from an ordinary CAN wiring fault because the module may communicate perfectly once awake but fail to wake on command, drain the battery by never sleeping, or lose track of scheduled wake events after a clock fault. A shorted or open wake-up wire, a module stuck awake, or a dead internal clock circuit are the usual causes.

These 10 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 10 times.

Codes in this family (10)

Code	Definition	Repair coverage
U3012	Control Module Improper Wake-up Performance	4 ranked fixes
U3017	Control Module Timer/Clock Performance	4 ranked fixes
U301A	Control Module Wake-up Circuit A/Open	4 ranked fixes
U301B	Control Module Wake-up Circuit A Low	4 ranked fixes
U301C	Control Module Wake-up Circuit A High	4 ranked fixes
U301D	Control Module Wake-up Circuit A Performance	4 ranked fixes
U301E	Control Module Wake-up Circuit B/Open	4 ranked fixes
U301F	Control Module Wake-up Circuit B Low	4 ranked fixes
U3020	Control Module Wake-up Circuit B High	4 ranked fixes
U3021	Control Module Wake-up Circuit B Performance	4 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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