OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Network generic or reserved

U3012

Control Module Improper Wake-up Performance

The control module did not wake up cleanly from sleep mode — wake event timing or sequence outside spec.

SystemNetwork
Typegeneric or reserved
GroupU3
Range / number– / 12

Possible causes

  • Module internal fault high
  • Wake signal noise or glitch medium
  • Gateway module routing CAN messages incorrectly low

Symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–1500 €
  • Estimated time: 1–5 h
  • Component: control module
  • Component: wakeup circuit
  • MIL / check engine light

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication