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 / SAE

U0024

Low Speed CAN Communication Bus Off

The low-speed CAN controller has gone bus-off after repeated error frames. The fault-tolerant single-wire fallback is exhausted and the bus stops carrying traffic.

SystemNetwork
Typegeneric / SAE
GroupU0
Range / number– / 24

Possible causes

  • Wiring short keeps bus in bus-off high
  • One failing node spamming errors 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: hard
  • DIY: shop recommended
  • Estimated cost: 80–700 €
  • Estimated time: 1–5 h
  • Component: low speed can wiring
  • Component: body control module
  • 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