OBD-II code · Powertrain (generic)
P04FF Catalyst Heater Circuit Performance Bank 2
The catalyst heater on bank 2 is electrically intact but does not deliver the expected thermal effect - measured catalyst light-off time is longer than calibrated. Heater element ageing, increased contact resistance, or a partial winding failure are typical causes.
Is it safe to drive with P04FF?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyHeater element aged - reduced power output
- PossibleIncreased contact resistance in supply
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 2–6 h
- Emissions test
- Likely to fail
- Parts involved
- Electric Catalyst Heater B2
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.