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

U3001

Control Module Improper Shutdown Performance

The control module did not complete its shutdown sequence cleanly — power was lost before housekeeping (saving learned values, freeze frames, adaptations) finished.

SystemNetwork
Typegeneric or reserved
GroupU3
Range / number– / 01

Possible causes

  • Power supply lost before shutdown completed high
  • Bad ground connection 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: possible
  • Estimated cost: 50–500 €
  • Estimated time: 0.5–3 h
  • Component: control module
  • Component: module power supply
  • 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