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!

Powertrain generic / SAE

P0429

Catalyst Heater Control Circuit/Open (Bank 1)

The drive circuit for the heated catalyst on bank 1 is open. Heated catalysts use an electrical heating element to reach light-off temperature within seconds of cold start.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / 29

Possible causes

  • Heater element or wiring open high
  • Pin pushed back out of connector body low
  • Cracked solder joint inside the module or sensor low

Symptoms

  • Check engine light on
  • Failed emissions inspection
  • Possibly slightly increased fuel consumption
  • Sulfur (rotten egg) smell from exhaust under load

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 200–2000 €
  • Estimated time: 1–5 h
  • Component: catalyst heater
  • MIL / check engine light
  • emissions-relevant

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