Powertrain
generic / SAE
P04F8
Catalyst Heater Circuit Intermittent Bank 1
Same as P04F4 with intermittent or erratic signal - typically a connector or harness fault on the heater feed.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / F8
Possible causes
- Intermittent contact at connector high
- Connector with intermittent contact under vibration low
- Harness routed against vibrating component 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: 200–1500 €
- Estimated time: 1–4 h
- Component: electric catalyst heater b1
- Component: catalyst heater wiring b1
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012